STATOR VANE AND GAS TURBINE

Abstract

This stator vane is at least provided with a blade body disposed in a combustion gas flow channel through which a combustion gas flows, a shroud that defines a part of the combustion gas flow channel, and an impingement plate attached to the shroud. A partition rib extends from a blade body end to an inner wall surface of a peripheral wall, and a shelf is provided at a rib-less part of the inner wall surface of the peripheral wall excluding at least a part in which the partition rib extends to the inner wall surface of the peripheral wall.

Description

TECHNICAL FIELD

The present disclosure relates to a stator blade and a gas turbine.

Priority is claimed on Japanese Patent Application No. 2020-050065, filed on Mar. 19, 2020, the content of which is incorporated herein by reference.

BACKGROUND ART

For example, as a stator blade of a gas turbine, there is a stator blade disclosed in PTL 1. The stator blade disclosed in PTL 1 is exposed to a high-temperature combustion gas. Therefore, in PTL 1, an inner shroud or an outer shroud is cooled by being provided with an impingement plate.

CITATION LIST

Patent Literature

• [PTL 1] Japanese Unexamined Patent Application Publication No. 2008-286157

SUMMARY OF INVENTION

Technical Problem

In some cases, the stator blade as disclosed in PTL 1 may be designed to have increased rigidity so that the inner shroud or the outer shroud is not distorted due to thermal deformation. However, when the rigidity of the stator blade is increased, there is a possibility that thermal stress partially increases.

The present disclosure is made to solve the above-described problem, and an object of the present invention is to provide a stator blade and a gas turbine which can suppress thermal stress generation.

Solution to Problem

According to the present disclosure, in order to solve the above-described problem, there is provided a stator blade including at least a blade body disposed in a combustion gas flow path through which a combustion gas flows, and a shroud that defines a part of the combustion gas flow path. The shroud includes a shroud body including at least a bottom plate having a gas pass surface facing the combustion gas flow path, and an inner surface facing a counter-flow path side opposite to the gas pass surface, and an impingement plate attached to the shroud body and having a plurality of through-holes. The shroud body is formed to include the bottom plate, a peripheral wall protruding toward the counter-flow path side from a peripheral edge of the inner surface of the shroud body, a shelf formed along an inner wall surface of the peripheral wall, protruding to the counter-flow path side from the inner surface of the bottom plate, and supporting the impingement plate, and at least one or more partition ribs protruding to the counter-flow path side from the bottom plate, and joining the blade body and the peripheral wall on which the shelf is not formed. The impingement plate forms a cavity which is a space between the inner surface of the bottom plate and the inner wall surface of the peripheral wall.

Advantageous Effects of Invention

According to the stator blade of the present disclosure, thermal stress generation can be suppressed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic sectional view of a gas turbine according to an embodiment of the present disclosure.

FIG. 2 is a sectional view of a main part of the gas turbine according to the embodiment of the present disclosure.

FIG. 3 is a perspective view of a stator blade when the stator blade according to the embodiment of the present disclosure is viewed from a radial outer side.

FIG. 4 is a view when an inner shroud in FIG. 3 is viewed from a radial inner side.

FIG. 5 is a sectional view taken along line A-A in FIG. 4.

FIG. 6 is a sectional view illustrating a cross section taken along line B-B in FIG. 4.

FIG. 7 is a sectional view illustrating a cross section taken along line C-C in FIG. 4.

FIG. 8 is a sectional view illustrating a cross section taken along line D-D in FIG. 4.

FIG. 9 is a sectional view illustrating a cross section taken along line E-E in FIG. 4.

FIG. 10 is a view when an outer shroud in FIG. 3 is viewed from the radial outer side.

FIG. 11 is a sectional view taken along line F-F in FIG. 10.

FIG. 12 is a plan sectional view illustrating a combination of a seal groove and a seal member of the inner shroud.

FIG. 13 is a perspective view illustrating a combination of the seal groove and the seal member between a suction-side peripheral wall and an adjacent blade.

FIG. 14 is a modification example of the seal groove of the outer shroud.

DESCRIPTION OF EMBODIMENTS

Embodiments

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

<<Configuration of Gas Turbine>>

As illustrated in FIG. 1, a gas turbine 10 of the present embodiment includes a compressor 20 that compresses air A, a combustor 30 that combusts a fuel F in the air A compressed by the compressor 20 to generate a combustion gas, and a turbine 40 driven by the combustion gas.

The compressor 20 includes a compressor rotor 21 that rotates around an axis Ar, a compressor casing 25 that covers the compressor rotor 21, and a plurality of stator blade rows 26. The turbine 40 includes a turbine rotor 41 that rotates around the axis Ar, a turbine casing 45 that covers the turbine rotor 41, and a plurality of stator blade rows 46.

The compressor rotor 21 and the turbine rotor 41 are located on the same axis Ar, and are connected to each other to form a gas turbine rotor 11. For example, a rotor of a generator GEN is connected to the gas turbine rotor 11. The gas turbine 10 further includes an intermediate casing 14 disposed between the compressor casing 25 and the turbine casing 45. The compressor casing 25, the intermediate casing 14, and the turbine casing 45 are connected to each other to form a gas turbine casing 15. Hereinafter, an extending direction of the axis Ar will be referred to as an axial direction Da, a circumferential direction around the axis Ar will be simply referred to as a circumferential direction Dc, and a direction perpendicular to the axis Ar will be referred to as a radial direction Dr. In addition, the compressor 20 side with reference to the turbine 40 in the axial direction Da will be referred to as an upstream side Dau, and a side opposite thereto will be referred to as a downstream side Dad. In addition, a side closer to the axis Ar in the radial direction Dr will be referred to as a radial inner side Dri, and a side opposite thereto will be referred to as a radial outer side Dro.

The compressor rotor 21 includes a rotor shaft 22 extending in the axial direction Da around the axis Ar, and a plurality of rotor blade rows 23 attached to the rotor shaft 22. The plurality of rotor blade rows 23 are aligned in the axial direction Da. Each of the rotor blade rows 23 is configured to include a plurality of rotor blades 23a aligned in the circumferential direction Dc. A stator blade row 26 is disposed on each upstream side Dau of the plurality of rotor blade rows 23. Each stator blade row 26 is provided inside the compressor casing 25. Each of the stator blade rows 26 is configured to include a plurality of stator blades 26a aligned in the circumferential direction Dc.

The turbine rotor 41 includes a rotor shaft 42 extending in the axial direction Da around the axis Ar, and a plurality of rotor blade rows 43 attached to the rotor shaft 42. The plurality of rotor blade rows 43 are aligned in the axial direction Da. Each of the rotor blade rows 43 is configured to include a plurality of rotor blades 43a aligned in the circumferential direction Dc. A stator blade row 46 is disposed on each upstream side Dau of the plurality of rotor blade rows 43. Each stator blade row 46 is provided inside the turbine casing 45. Each of the stator blade rows 46 is configured to include a plurality of stator blades 50 aligned in the circumferential direction Dc.

As illustrated in FIG. 2, the turbine casing 45 includes a tubular outer casing 45a forming an outer shell thereof, an inner casing 45b fixed to the inside of the outer casing 45a, a plurality of split rings 90 fixed to the inside of the inner casing 45b, and a thermal barrier ring 45c that connects the stator blade 50 and the split ring 90 to the inner casing 45b. Each of the plurality of split rings 90 is provided at a position between the plurality of stator blade rows 46. Therefore, the rotor blade row 43 is disposed on the radial inner side Dri of each of the split rings 90.

Ar annular space between the rotor shaft 42 and the turbine casing 45 in the radial direction Dr where the stator blade 50 and the rotor blade 43a are disposed in the axial direction Da forms a combustion gas flow path 49 through which a combustion gas G from the combustor 30 flows. The combustion gas flow path 49 forms an annular shape around the axis Ar, and is long in the axial direction Da. A cooling air passage 45p penetrating the radial inner side Dri from the radial outer side Dro is formed in the inner casing 45b of the turbine casing 45. Cooling air passing through the cooling air passage 45p is introduced into the stator blade 50 and the split ring 90, and is used for cooling the stator blade 50 and the split ring 90.

<<Configuration of Turbine Stator Blade>>

As illustrated in FIG. 3, the stator blade 50 of the turbine 40 includes a blade body 51 extending in the radial direction Dr, an inner shroud 60i formed on the radial inner side Dri of the blade body 51, and an outer shroud 60o formed on the radial outer side Dro of the blade body 51. The blade body 51 is disposed inside the combustion gas flow path 49 through which the combustion gas G passes. The inner shroud 60i defines a position on the radial inner side Dri in the annular combustion gas flow path 49. The outer shroud 60o defines a position on the radial outer side Dro in the annular combustion gas flow path 49.

A hook 69 for supporting the stator blade 50 in the gas turbine casing 15 (outer casing 45a and inner casing 45b) is provided on a side closer to a trailing edge portion 53 of the blade body 51 in the outer shroud 60o or the stator blade 50. The hook 69 of the stator blade 50 is provided on a rear peripheral wall 62b of the outer shroud 60o. The hook 69 of the stator blade 50 is fitted to the thermal barrier ring 45c supported by the inner casing 45b. In this way, the stator blade 50 is supported by the gas turbine casing 15 via the thermal barrier ring 45c.

As illustrated in FIGS. 3 to 5, the blade body 51 has a blade shape. The blade body 51 extends in the radial direction Dr, is connected to the inner shroud 60i on the radial inner side Dri, and is connected to the outer shroud 60o on the radial outer side Dro. The blade body 51 is integrated with the inner shroud 60i and the outer shroud 60o to form the stator blade 50. Each of blade body end portions 51r on the radial inner side Dri and the radial outer side Dro of the blade body 51 slightly protrudes to the radial inner side Dri and the radial outer side Dro from an inner surface 64i of a bottom plate 64 of the inner shroud 60i and the outer shroud 60o. In FIG. 4, an impingement plate 81 is omitted in the illustration.

The blade body 51 includes a leading edge portion 52 on the upstream side Dau and a trailing edge portion 53 on the downstream side Dad. The blade body 51 further includes suction side surface 54 (=negative pressure surface) forming a projecting surface and a pressure-side surface 55 (=positive pressure surface) forming a recessed surface, out of surfaces facing the circumferential direction Dc of the surface of the blade body 51. For convenience of the following description, a pressure-side (=positive pressure surface side) of the blade body 51 in the circumferential direction Dc will be referred to as a circumferential pressure-side Dcp, and a suction-side (=negative pressure surface side) of the blade body 51 will be referred to as a circumferential auction-side Dcn. In addition, the upstream side Dau in the axial direction Da may be referred to as a front side, and the downstream side Dad in the axial direction Da may be referred to as a rear side.

A illustrated in FIGS. 3 and 5, the blade body 51 includes a blade air passage 75 extending in the radial direction Dr. The blade air passage 75 is continuously formed in a range from the outer shroud 60o to the inner shroud 60i. In the present embodiment, a case is illustrated where three blade air passages 75 are aligned in a leading edge-trailing edge direction connecting the leading edge portion 52 and the trailing edge portion 53 of the blade body 51. The blade air passages 75 adjacent to each other may communicate with each other in a portion on the radial outer side Dro or in a portion on the radial inner side Dri. In addition, any one of a plurality of blade air passages 75 may be open on the radial outer side Dro. In the present embodiment, a case is illustrated where the blade air passage 75 closest to the leading edge portion 52 is open on the outer shroud 60o side (refer to FIG. 3).

As illustrated in FIGS. 3 and 5, the blade body end portion 51r is formed by forming the blade body 51 in both end portions on the radial inner side Dri and the radial outer side Dro. Specifically, in the blade body 51, the blade body end portion 51r formed on the radial inner side Dri protrudes to the radial inner side Dri which is the counter-flow path side from the inner surface 64i (refer to FIGS. 4 and 5) of the inner shroud body 61i. The blade body end portion 51r (refer to FIG. 3) on the radial outer side Dro protrudes to the radial outer side Dro which is the counter-flow path side from the inner surface 64i of the outer shroud body 61o. An outer shape cross section of the blade body end portion 51r formed on the radial inner side Dri when viewed from the radial inner side Dri and an outer shape cross section when the blade body end portion 51r formed on the radial outer side Dro is viewed from the radial outer side Dro respectively form blade shapes. The blade body end portion 51r is formed integrally with the blade body 51.

<<Configuration of Inner Shroud>>

As illustrated in FIGS. 3 to 5, the inner shroud 60i is configured to include an inner shroud body (shroud body) 61i and an impingement plate 81 (to be described later) accommodated inside the inner shroud body 61i and having a plurality of through-holes.

The inner shroud body 61i is configured to include a bottom plate 64 forming the inner surface 64i of the above-described inner shroud body 61i, a peripheral wall 65i disposed around the bottom plate 64, a partition rib 60r (to be described later) that partitions a space (cavity 67) inside the inner shroud body 61i, and a shelf 71i that supports the impingement plate 81. The peripheral wall 65i includes a front peripheral wall 62f and a rear peripheral wall 62b which face each other in the axial direction Da, and a pressure-side peripheral wall 63p and a suction-side peripheral wall 63n which face each other in the circumferential direction Dc, and the peripheral wall 65i is disposed around the bottom plate 64, thereby forming the inner shroud body 61i. A recessed portion 66 recessed to the radial outer side Dro from the counter-flow path side is formed inside the inner shroud body 61i. An end surface on the upstream side Dau of the front peripheral wall 62f forms a front end surface 62fa, and an end surface on the downstream side Dad forms a rear end surface 62ba. Out of a pair of end surfaces facing opposite sides in the circumferential direction Dc, an end surface of the pressure-side peripheral wall 63p located on the circumferential pressure-side Dcp forms a pressure-side end surface 63pa, and an end surface on the suction-side peripheral wall 63n located on the circumferential suction-side Dcn forms a suction-side end surface 63na. In addition, the bottom plate 64 of the inner shroud body 61i includes a gas pass surface 64p facing the radial outer side Dro and an inner surface (counter-flow path surface) 64i facing the radial inner side Dri which is the counter-flow path side opposite to the gas pass surface 64p.

In the inner shroud 60i described as an example in the present embodiment, the front peripheral wall 62f and the rear peripheral wall 62b are substantially parallel to each other, and the pressure-side peripheral wall 63p and the suction-side peripheral wall 63n are substantially parallel to each other. Therefore, when viewed in the radial direction Dr, the inner shroud body 61i has a parallel quadrilateral shape.

The pressure-side peripheral wall 63p of the inner shroud 60i of one stator blade 50 of the two stator blades 53 (not illustrated) adjacent to each other in the circumferential direction Dc is disposed to face the suction-side peripheral wall 63n of the inner shroud 60i of the other stator blade 50 with a gap in the circumferential direction Dc.

As described above, the peripheral wall 65i includes the front peripheral wall 62f and the rear peripheral wall 62b which face each other in the axial direction Da, and the pressure-side peripheral wall 63p and the suction-side peripheral wall 63n which face each other in the circumferential direction Dc.

The pressure-side peripheral wall 63p forms a portion of the peripheral wall 65i which is located on the circumferential pressure-side Dcp, and the suction-side peripheral wall 63n forms a portion of the peripheral wall 65i which is located on the circumferential suction-side Dcn.

Both the front peripheral wall 62f and the rear peripheral wall 62b protrude to the radial inner side Dri from the pressure-side peripheral wall 63p and the suction-side peripheral wall 63n with respect to the inner shroud body 61i.

<<Configuration of Partition Rib of Inner Shroud>>

A plurality of partition ribs 60r are formed in the inner shroud 60i. The partition rib 60r protrudes to the radial inner side Dri from the inner surface 64i of the inner shroud body.

The partition rib 60r joins the blade body end portion 51r of the blade body 51 and the inner wall surface 65a of the peripheral wall 65i of the inner shroud 60i. Five partition ribs 60r are formed in the inner shroud 60i of the present embodiment. The blade body 51, the inner shroud body 61i, the outer shroud body 61o, and the partition rib 60r are integrally formed by means of casting. As a result, a space (cavity 67) which is the recessed portion 66 of the inner shroud 60i forms the cavity 67 partitioned into a plurality of spaces in such a manner that the recessed portion 66 is partitioned by disposing the plurality of partition ribs 60r between the blade body end portion 51r and the peripheral wall 65i. In addition, a height from the inner surface 64i of the inner shroud 60i of the blade body end portion 51r which is an end portion outside and inside in the radial direction Dr of the blade body 51 is the same height as the partition rib 60r. However, the height may be changed depending on a shape of the shroud.

In the present embodiment, each one of the partition ribs 60r is provided between the leading edge portion 52 on the most upstream side Dau of the blade body end portion 51r and the inner wall surface 65a of the front peripheral wall 62f of the peripheral wall 65i, between the trailing edge portion 53 or the most downstream side Dad of the blade body end portion 51r and the inner wall surface 65a of the rear peripheral wall 62b of the peripheral wall 65i, and between the blade body end portion 51r on the suction-side surface 54 side and the inner wall surface 65a of the suction-side peripheral wall 63n of the peripheral wall 65i. In addition, two partition ribs 60r are provided at an interval in the axial direction Da between the blade body end portion 51r of the pressure-side surface 55 and the inner wall surface 65a of the pressure-side peripheral wall 63p of the peripheral wall 65i. The number and disposition of the partition ribs 60r formed in the inner shroud 60i are examples, and are not limited to the above-described configuration. The plurality of partition ribs 60r for joining the blade body end portion 51r and the peripheral wall 65i are disposed in the recessed portion 66 inside the inner shroud 60i. In this manner, the recessed portion 66 is partitioned into the plurality of spaces to form a plurality of the cavities 67. The cavity 67 is partitioned into a plurality of cavities. In this manner, the cooling air can be held for each of the cavities 67 independently of each other under different conditions.

As illustrated in FIG. 4, one end of the partition rib 60r is connected to the blade body end portion 51r of the blade body 51, and the other end of the partition rib 60r is connected to the inner wall surface 65a of the peripheral wall 65i. That is, the tip of the partition rib 60r from each of the blade body end portions 51r of the leading edge portion. 52, the trailing edge portion. 53, the suction-side surface 54, and the pressure-side surface 55 of the blade body 51 extends to the inner wall surface 65a of the peripheral wall 65i.

<<Concept of Thermal Stress Generated in Shroud %>

As one of the embodiments according to the present invention, in some cases, a structure for partially forming the shelf 71 (71i, 71o) may be applied along the inner wall surface 65a of the peripheral wall 65 (65i, 65o) of the shroud 60 (60i, 60o) instead of the entire periphery of the peripheral wall 65. Significance of a shroud structure which can reduce local thermal stress of the shroud 60 while suppressing thermal strain or thermal deformation of the whole shroud 60 will be described below.

In general, as means for cooling the shroud 60, the impingement plate 81 is disposed inside the shroud 60, the cooling air is supplied to the shroud 60 from the outside, and the inner surface of the shroud 60 is subjected to impingement cooling (collision cooling). On the other hand, as means for improving the impingement cooling of the shroud 60, in some cases, the plurality of partition ribs 60r may be formed inside the shroud 60, the cavity 67 inside the shroud 60 may be divided into the plurality of cavities, and conditions of the cooling air supplied to each of the cavities 67 may be changed to perform optimum impingement cooling on the shroud 60. In this case, a structure for individually fixing the impingement plate 81 to each of the plurality of divided cavities 67 by means of welding may be adopted. In some cases, the thermal strain or the thermal deformation may occur in the shroud 60 due to a heat input caused by welding heat when the impingement plate 81 is welded and fixed. In order to suppress occurrence of the thermal strain or the thermal deformation of the shroud 60, the shelf 71 can be formed along the inner wall surface 65a of the peripheral wall 65 to increase rigidity of the shroud 60. In this manner, the thermal strain or the thermal deformation of the shroud 60 can be suppressed.

On the other hand, although the rigidity of the shroud 6C is increased by disposing the shelf 71 along the inner wall surface 65a of the peripheral wall 65, in some cases, the thermal stress may locally increase depending on the structure of the shroud 60. For example, as illustrated in FIGS. 2 and 3, when the outer shroud 60o is described as an example, the stator blade 50 is supported by the gas turbine casing 15 via the hook 69 and the thermal barrier ring 45c which are formed in the outer shroud 60c. When the gas turbine 10 enters a normal operation, a temperature difference occurs between the stator blade 50 and the gas turbine casing 15 that supports the stator blade 50, and a thermal elongation difference in the circumferential direction Dc occurs in a fitting portion 69a between the hook 69 and the thermal barrier ring 45c. That is, due to the heat input from the combustion gas side, in the outer shroud 60o, deformation in which the suction-side end surface 63na side and the pressure-side end surface 63pa side warp in a direction of the radial outer side Dro occurs around a center line in the leading edge-trailing edge direction (in FIG. 10, a line parallel to the suction-side end surface 63na or the pressure-side end surface 63pa, which is a center line in the circumferential direction Dc of the outer shroud 60o and a line connecting an intermediate position in the circumferential direction Dc of the front end surface 62fa and an intermediate position in the circumferential direction Dc of the rear end surface 62ba). However, the thermal barrier ring 45c side fitted to the hook 69 is maintained at a relatively low temperature, and the thermal deformation is small. Accordingly, the deformation on the hook 69 side is restricted by the fitting portion 69a between the hook 69 and the thermal barrier ring 45c. Due to the restriction of the fitting portion 69a, the thermal stress is generated between the suction-side end surface 63na and the pressure-side end surface 63pa in the circumferential direction of the rear peripheral wall 62b of the outer shroud 60o.

On the other hand, due to the thermal elongation difference between the blade body 51 and the rear peripheral wall 62b and the front peripheral wall 62f which are connected via the partition ribs 60r (first partition rib 60rf, second partition rib 60rb), in some cases, high thermal stress may be generated in the rear peripheral wall 62b and the front peripheral wall 62f. That is, in the blade body 51, the thermal elongation of the blade body 51 is suppressed to be relatively small by the cooling air supplied to the blade air passage 75. On the other hand, the rear peripheral wall 62b and the front peripheral wall 62f tend to suffer thermal elongation in the circumferential direction Dc due to the heat input from the combustion gas. Therefore, the rear peripheral wall 62b and the front peripheral wall 62f receive the restriction from the partition rib 60r (first partition rib 60rf, second partition rib 60rb) that joins the leading edge portion 52 side and the trailing edge portion 53 side of the blade body 51 to the peripheral wall 65. In this manner, in some cases, the high thermal stress may be generated in a predetermined region of the peripheral walls 65i and 65o around a joining portion joined to the partition rib 60r (first partition rib 60rf, second partition rib 60rb) on the rear peripheral wall 62b and the front peripheral wall 62f. Therefore, in order to reduce the thermal stress, a trailing edge end portion passage 80 and a trailing edge purge cooling hole 91 (to be described later) are disposed in the inner shroud 60i and the outer shroud 60o.

The above-described concept of the thermal stress is a concept mainly applied to the outer shroud 60o. In a case of the inner shroud 60i, as described above, the inner shroud 60i is less affected by the thermal stress generated due to the restriction of the fitting portion 69a between the hook 69 of the outer shroud 60o and the thermal barrier ring 45c.

In a case of the inner shroud 60i, compared to the outer shroud 60o, the structure does not receive the restriction from the outside due to the thermal elongation difference. As described above, the structure is limited to a case where the high thermal stress is generated in the rear peripheral wall 62b and the front peripheral wall 62f due to the thermal elongation difference between the blade body 51 and the rear peripheral wall 62b and the front peripheral wall 62f which are connected via the partition rib 60r (first partition rib 60rf, second partition rib 60rb). However, the inner shroud 60i is less affected by the thermal stress, compared to the outer shroud 60c. Therefore, a range for disposing the trailing edge purge cooling hole 91 is limited.

<<Range for Disposing Shelf of Inner Shroud>>

As illustrated in FIG. 4, the peripheral wall 65i of the inner shroud 60i has four corners, a first corner C1, a second corner C2, a third corner C3, and a fourth corner C4 on the inner wall surface 65a. The first corner C1 is formed by the inner wall surface 65a of the suction-side peripheral wall 63n and by the inner wall surface 65a of the front peripheral wall 62f. The second corner C2 is formed by the inner wall surface 65a of the pressure-side peripheral wall 63p and by the inner wall surface 65a of the front peripheral wall 62f. The third corner C3 is formed by the inner wall surface 65a of the suction-side peripheral wall 63n and by the inner wall surface 65a of the front peripheral wall 62f. The fourth corner C4 is formed by the inner wall surface 65a of the pressure-side peripheral wall 63p and by the inner wall surface 65a of the rear peripheral wall 62b. In the inner shroud 60i in the present embodiment, the shelves 71i are formed in the first corner C1, the second corner C2, the third corner C3, and the fourth corner C4.

As illustrated in FIG. 4, in a case of the inner shroud 60i, a plurality of trailing edge end portion passages 80 (to be described later) are arrayed over the entire width from the suction-side end surface 63na to the pressure-side end surface 63pa on the rear peripheral wall 62b disposed on the trailing edge portion 53 side of the inner shroud 60i. Furthermore, in order to partially improve the cooling on the gas pass surface side of the rear peripheral wall 62b in which the trailing edge circumferential passage 79 of the rear peripheral wall 62b is disposed, a plurality of arrayed trailing edge purge cooling holes 91 (first purge cooling holes 91i) are disposed in a predetermined range in the circumferential direction Dc while the partition rib 60r (second partition rib 60rb) that joins the trailing edge portion 53 of the blade body 51 and the rear peripheral wall 62b is interposed therebetween.

Meanwhile, as described above, the rear peripheral wall 62b and the front peripheral wall 62f tend to be elongated in the circumferential direction Dc due to the heat input from the combustion gas. However, the thermal elongation is restricted by the partition ribs 60r (first partition rib 60rf, second partition rib 60rb) that join the blade body end portion 51r of the blade body 51 and the inner wall surface 65a of the rear peripheral wall 62b and of the front peripheral wall 62f. The high thermal stress partially acts on the rear peripheral wall 62b and the front peripheral wall 62f in the circumferential direction Dc around a joining portion joined to the partition ribs 60r (first partition rib 60rf, second partition rib 60rb).

Therefore, as illustrated in FIG. 4, in a case of the rear peripheral wall 62b, on the inner wall surface 65a of the rear peripheral wall 62b, a shelf 71ic including the third corner C3 and extending to the circumferential pressure-side Dcp, and a shelf 71id including the fourth corner C4 and extending to the circumferential suction-side Dcn are disposed. Between the shelf 71ic and the shelf 71id, a region 73 that does not form the shelves is disposed on both sides in the circumferential direction Dc while the partition rib 60r (second partition rib 60rb), an intermediate shelf 71im (71i), and an intermediate shelf 71im (71i) are interposed therebetween. A position where the partition rib 60r (second partition rib 60rb) is connected to the peripheral wall 65i is disposed within a range where the trailing edge purge cooling hole 91 (first purge cooling hole 91i) (to be described later) formed on the rear peripheral wall 62b is formed in the circumferential direction Dc. In a case of the rear peripheral wall 62b, the thermal stress increases the most in the vicinity of a position Pc where the partition rib 60r (second partition rib 60rb) is joined to the peripheral wall 65i. The thermal stress gradually decreases from the position Pc toward the circumferential suction-side Dcn and the circumferential pressure-side Dcp. The shelves 71ic (71i) and 71id (71i) are formed in a range from a position where the thermal stress is equal to or smaller than an allowable value from the position Pc toward the circumferential suction-side Dcn to the third corner C3 and in a range from the position to the fourth corner C4 toward the circumferential pressure-side Dcp.

The intermediate shelf 71im disposed between the position Pc of the second partition rib 60rb and the shelf 71ic (71i) has the same width and the same height as those of the shelf 71ic (71i). The length in the circumferential direction Dc is substantially the same as the width of the shelf, and the intermediate shelf 71im has a substantially rectangular cross section. The intermediate shelf 71im (71i) has a small cross-sectional shape, and serves as the shelf for receiving the impingement plate 81. That is, in the region 73 where the shelf is not formed between the position Pc of the second partition rib 60rb and the shelf 71ic (71i) on the third corner C3 side, the intermediate shelf 71im (71i) is provided for positioning in the radial direction Dr when the impingement plate 81 is fixed to the inner wall surface 65a of the rear peripheral wall 62b. The thermal stress generated on the rear peripheral wall 62b is hardly affected by the presence or absence of the intermediate shelf 71im (71i). The intermediate shelf 71im (711) is formed integrally with the shelf 71ic (71i) and the shelf 71id (71i) during the casting of the blade body 51. When positioning in the radial direction Dr can be separately performed by using a jig, the intermediate shelf 71im (71i) may not be provided.

As illustrated in FIG. 4, the position Pc of the second partition rib 60rb in the circumferential direction Dc is an intermediate position in the circumferential direction Dc of the width from the suction-side end surface 63na to the pressure-side end surface 63pa of the inner shroud body 61i, and is close to the pressure-side end surface 63pa side. The length of the region 73 where the shelf 71 is not formed from the position Pc of the second partition rib 60rb to an end portion of the circumferential pressure-side Dcp of the shelf 71ic (71i) is longer than the length of the region 73 where the shelf 71 is not formed from the position Pc to an end portion of the circumferential suction-side Dcn of the shelf 71id (71i). The reason is as follows. The suction-side end surface 63na side is more affected by the thermal stress than the pressure-side end surface 63pa side in the circumferential direction Dc around the second partition rib 60rb. The position in the circumferential direction Dc of the intermediate shelf 71im (71i) is disposed closer to the circumferential suction-side Dcn than the position of the first purge cooling hole 91i closest to the suction-side end surface 63na of the first purge cooling holes 91i.

The region where the shelf 71 is not formed between the shelf 71ic (71i) and the shelf 71id (71i) is disposed on both sides in the circumferential direction Dc while the second partition rib 60rb is interposed therebetween. In this manner, the thermal stress generated in the rear peripheral wall 62b is reduced.

In a case of the front peripheral wall 62f, the concept of the thermal stress acting on the front peripheral wall 62f is the same as that of the rear peripheral wall 62b.

However, since the heat input from the combustion gas is small, there is less thermal stress generated on the front peripheral wall 62f. A case of the front peripheral wall 62f does not include a cooling structure such as the trailing edge end portion passage 80 and the trailing edge purge cooling hole 91. Similar to the rear peripheral wall 62b, a shelf 71ia including the first corner C1 and extending to the circumferential pressure-side Dcp and a shelf 71ib including the second corner C2 and extending to the circumferential suction-side Dcn are disposed on the inner wall surface 65a of the front peripheral wall 62f. The region 73 where the shelf 71 is not formed is provided between the shelf 71ia and the shelf 71ib, and the first partition rib 60rf interposed from both sides in the circumferential direction Dc is disposed in the region.

The thermal stress generated on the front peripheral wall 62f is reduced by disposing the region where the shelves 71 are not formed on both sides in the circumferential direction Dc while the first partition rib 60rf is interposed therebetween.

The region 73 where the shelf 71 is not formed (portion having no shelf) extends to the suction-side peripheral wall 63n and the pressure-side peripheral wall 63p, except for some shelves extending in the axial direction Da (leading edge-trailing edge direction) from the first corner C1, the second corner C2, the third corner C3, and the fourth corner C4 which are end portions of the shelf 71ic disposed on the rear peripheral wall 62b, the shelf 71id, the shelf 71ia disposed on the front peripheral wall 62f, and the shelf 71ib. In addition, the reason that the shelf 71 is not disposed along the inner wall surface 65a of the suction-side peripheral wall 63n and of the pressure-side peripheral wall 63p is as follows. Compared to the front peripheral wall 62f and the rear peripheral wall 62b, the thermal strain or the thermal deformation caused by welding heat of the impingement plate 81 is relatively smaller.

<<Configuration Around Shelf of Inner Shroud>>

As illustrated in FIGS. 4 and 5, the shelf 71 for supporting the impingement plate is provided in the inner shroud 60i. The shelf 71 protrudes to the radial inner side Dri from the inner surface 64i of the bottom plate 64 of the inner shroud body 61i along the inner wall surface 65a of the peripheral wall 65i. That is, the shelf 71 protrudes to the counter-flow path side on a side opposite to the gas pass surface 64p (combustion gas flow path side) in the radial direction Dr with reference to the inner surface 64i of the bottom plate 64 of the inner shroud body 61i. The shelf 71 has a support surface 72 facing the radial inner side Dri side which is the counter-flow path side with respect to the gas pass surface 64p on the flow path side, and supports the impingement plate 81.

As illustrated in FIG. 5, the support surface 72 is located on a side closer to the inner surface 64i of the bottom plate 64 of the inner shroud body 61i than an end portion 65t of the peripheral wall 65i in the radial direction Dr. In addition, the support surface 72 of the shelf 71 is located on the radial inner side Dri in the radial direction Dr from the end portion of the partition rib 60r described above. In other words, the height of the shelf 71 with reference to the inner surface 64i of the inner shroud body 61i in the radial direction Dr is lower than the height of the peripheral wall 65i with reference to the same inner surface 64i. In addition, in the present embodiment, the thickness of the shelf 71i in a direction protruding inward from the inner wall surface 65a of the peripheral wall 65i is thinner than the thickness of the peripheral wall 65i in the same direction as the direction of the thickness of the shelf 71.

As illustrated in FIG. 5, a surface 65fa (FIG. 9) facing the radial inner side Dri of the suction-side peripheral wall 63n and the pressure-side peripheral wall 63p is formed closer to the inner surface 64i of the bottom plate 64 than the position of a surface 65ta facing the radial inner side Dri of the end portion 65t of the front peripheral wall 62f and of the rear peripheral wall 62b, and is formed at substantially the same height as the position of the support surface 72 of the shelf 71.

<<Configuration of Impingement Plate of Inner Shroud>>

The impingement plate 81 illustrated in FIG. 5 is attached to the inner shroud 60i. The impingement plate 81 partitions the space (cavity 67) inside the recessed portion. 66 of the inner shroud 60i into an outer cavity 67b in a region on the radial inner side Dri and into an inner cavity 67a in a region on the radial outer side Dro. A plurality of through-holes 82a penetrating in the radial direction Dr are formed in the impingement plate 31. A portion of cooling air Ac existing on the radial inner side Dri of the stator blade 50 flows into the inner cavity 67a via the through-hole 82a of the impingement plate 81, and performs impingement cooling (collision cooling) on the bottom plate 64 of the inner shroud 60i.

As illustrated in FIGS. 6 to 9, the impingement plate 81 includes a main body portion 82 including the plurality of through-holes 82a, a strain absorber 83 that absorbs the thermal strain of the main body portion 82, and a fixing portion 84 that fixes the main body portion 82 to the shroud 60.

As described above, the main body portion 82 is a member including the plurality of through-holes 82a and extending parallel to the inner surface 64i of the bottom plate 64 of the inner shroud body 61i to the inner wall surface 65a of the peripheral wall 65i.

FIG. 6 is a sectional view illustrating a cross section taken along line B-B in FIG. 4. The embodiment illustrated in FIG. 6 has a structure in which the main body portion 82 extends in the axial direction Da (leading edge-trailing edge direction) while maintaining the same height parallel to the inner surface 64i of the bottom plate 64. An aspect is adopted as follows. A first edge 81a which is an end surface of the main body portion 82 abuts against and is fixed to the inner wall surface 65a of the region 73 where the shelf 271 is not provided on the inner wall surface 65a of the peripheral wall 65i. The first edge 81a which is an abutting end surface with respect to the inner wall surface 65a of the peripheral wall 65i is joined to the inner wall surface 65a of the peripheral wall 65i via a welding portion 81W formed by fillet welding.

FIG. 7 is a sectional view illustrating a cross section taken along line C-C in FIG. 4. The embodiment illustrated in FIG. 7 indicates an attachment structure of the impingement plate 81 in a region where the shelf 71 is formed on the inner wall surface 65a of the peripheral wall 65i.

In the present embodiment, an aspect includes a structure in which the shelf 71 (71i) is disposed between the main body portion 82 and the inner wall surface 65a of the peripheral wall 65i, and the strain absorber 83 extending in the radial direction Dr and the fixing portion 84 are disposed in the impingement plate 81. The strain absorber 83 is a member bent with a predetermined inclination with respect to the axial direction Da in which the main body portion 82 extends, and extends in the radial direction Dr. The strain absorber 83 is connected to the main body portion 82 via a first bent portion 83a on the radial inner side Dri, and is connected to the fixing portion 84 (to be described later) via a second bent portion 83b on the radial outer side Dro.

The fixing portion 84 is connected to the second bent portion 83b of the strain absorber 83, and extends in the axial direction Da (leading edge-trailing edge direction). That is, the strain absorber 83 in the present embodiment extends in a vertical direction intersecting both the main body portion 82 and the fixing portion 84. The strain absorber 83 is disposed to be separated by a predetermined distance or longer from the shelf 71 to which the fixing portion 84 of the impingement plate 81 is fixed and the inner wall surface 65a of the peripheral wall 65i. In this manner, even when the main body portion 82 of the impingement plate 81 is thermally elongated in the axial direction Da and the circumferential direction Dc, the thermal elongation of the main body portion 82 is absorbed by the deformation of the strain absorber 83. Therefore, the thermal stress acting on the welding portion 81W of the second edge 81b which is an end surface of the impingement plate 81 is reduced.

FIG. 8 is a sectional view illustrating a cross section taken along line D-D in FIG. 4. In the embodiment illustrated in FIG. 8, an aspect of the following case is adopted. A range where the shelf is not formed between the first partition rib 60rf and the shelf 71ia is narrow in the circumferential direction Dc, and the strain absorber 83 of the impingement plate 81 is less likely to be processed, or is less likely to be attached. As illustrated in FIG. 8, when the impingement plate 81 is attached to the peripheral wall 65i in a narrow space region where the shelf 71 is not formed, a gap between the strain absorber 83 and the inner wall surface 65a of the peripheral wall 65i has to be larger, compared to a gap between the strain absorber 83 and the inner wall surface of the shelf 71 in an aspect where the shelf 71 illustrated in FIG. 7, is formed. When the region 73 where the shelf 71 is not formed is long and the gap is excessively large, in some cases, a corner portion where the peripheral wall 65i and the bottom plate 64 are connected may be insufficiently cooled. In this case, as illustrated in FIG. 8, a through-hole 82b which is an inclined passage facing the radial inner side Dri may be provided in the vicinity of the first bent portion 83a of the strain absorber 83.

In a structure of attaching the fixing portion 84 to the peripheral wall 65i which is a structure of the impingement plate 81 including the strain absorber 83, the structure adopts any one of a method of fixing to the surface 65fa (refer to FIG. 9) facing the radial inner side Dri on the peripheral wall 65i, a method of fixing to the support surface 72 (refer to FIG. 7) which is a surface facing the radial inner side Dri in the shelf 71, and a method (refer to FIG. 8) of fixing to the region 73 where the shelf 71 is not formed on the inner wall surface 65a of the peripheral wall 65i.

FIG. 9 is a sectional view illustrating a cross section taken along line E-E in FIG. 4. The embodiment illustrated in FIG. 9 is an aspect in which the impingement plate 81 is attached to the suction-side peripheral wall 63n and the pressure-side peripheral wall 63p. According to the structure, the shelf 71 is not provided on the inner wall surface 65a of the suction-side peripheral wall 63n and of the pressure-side peripheral wall 63p. The fixing portion 84 of the impingement plate 81 having the strain absorber 83 is placed on the surface 65fa facing the radial inner side Dri of the peripheral wall 65i. The fixing portion 84 is directly fixed to the peripheral wall 65i.

In a case of the suction-side peripheral wall 63n and the pressure-side peripheral wall 63p, the effect of welding strain is less when the impingement plate 81 is welded to the peripheral wall 65i.

As illustrated in FIG. 5, as described above, the impingement plate 81 is fixed to the peripheral wall 65i on the outer peripheral side of the inner shroud 60i, and is fixed onto the blade body end portion 51r of the blade body on the inner peripheral side of the inner shroud 60i. The main body portion 82 fixed to the blade body 51 side of the impingement plate 81 is placed on an end surface facing the radial outer side Dro of the blade body end portion 51r while the same height as that of the main body portion 82 in the vicinity of the peripheral wall 65i is maintained. The main body portion 82 is welded and fixed to the blade body end portion 51r in a third edge 81c.

As illustrated in FIG. 4, the plurality of trailing edge purge cooling holes 91 (first purge cooling holes 91i) are formed on the rear peripheral wall 62b of the inner shroud 60i. One end of the plurality of first purge cooling holes 91i is open to the inner surface 64i of the inner shroud body 61i on a side closer to the rear peripheral wall 62b on the downstream side Dad from the blade body 51, which is the trailing edge portion 53 side on the downstream side Dad from the blade body 51. The other end of the plurality of first purge cooling holes 91i is open to a discharge opening 91ia formed on the gas pass surface 64p. The plurality of first purge cooling holes 91i are formed in parallel in the extending direction (circumferential direction Dc) of the rear peripheral wall 62b. The plurality of first purge cooling holes 91i are formed only in the extending direction of the rear peripheral wall 62b which is the region 73 where the shelf 71 is not formed between the shelf 71id and the intermediate shelf 71im while the second partition rib 60rb is interposed therebetween. Since the plurality of first purge cooling holes 91i are provided, in the region 713 where the shelf 71 is not formed between the shelf 71id and the intermediate shelf 71im around the second partition rib 60rb, which is the region on the upstream side Dau of the rear peripheral wall 62b, a cooling effect that improves a convection cooling effect obtained by a cooling passage system (to be described later) is generated to improve an effect of reducing the thermal stress on the rear peripheral wall 62b.

As described above, the cooling passage system is provided on the rear peripheral wall 62b from the viewpoint of reducing the thermal stress on the rear peripheral wall 62b. As lustrated in FIG. 4, the cooling passage system is formed by a suction-side passage 78n, a pressure-side passage 78p, the trailing edge circumferential passage 79, and the trailing edge end portion passage 80. The suction-side passage 78n is open to the inner cavity 67a on the upstream side, and extends to the downstream side Dad inside the suction-side peripheral wall 63n. The pressure-side passage 78p is open to the inner cavity 67a on the upstream side, and extends to the downstream side Dad inside the pressure-side peripheral wall 63p. The trailing edge circumferential passage 79 extends in the circumferential direction Dc inside the rear peripheral wall 62b, is connected to the suction-side passage 78n in an end of the circumferential suction-side Dcn, and is connected to the pressure-side passage 78p in an end of the circumferential pressure-side Dcp. The plurality of trailing edge end portion passages 80 are arrayed in the circumferential direction Dc and are connected to the trailing edge circumferential passage 79 on the upstream side Dau, and the downstream side Dad is open to the rear end surface 62ba.

The cooling air supplied from the outside to the outer cavity 67b of the inner shroud 60i is discharged to the inner cavity 67a via the through-hole 82a formed in the impingement plate 81, and impingement cooling (collision cooling) is performed on the bottom plate 64 of the inner shroud body 61i. The cooling air after the impingement cooling is supplied to the suction-side passage 78n and the pressure-side passage 78p, convection cooling is performed on the suction-side peripheral wall 63n and the pressure-side peripheral wall 63p, and thereafter, the cooling air is supplied to the trailing edge circumferential passage 79. The cooling air is further supplied from the trailing edge circumferential passage 79 to the trailing edge end portion passage 80, convection cooling is performed on the rear peripheral wall 62b, and thereafter, the cooling air is discharged to the combustion gas from the opening of the rear end surface 62ba. Since the cooling passage system is disposed, the rear peripheral wall 62b is cooled, and the thermal stress of the rear peripheral wall 62b is reduced.

<Configuration of Outer Shroud>

As illustrated in FIGS. 3, 10, and 11, similar to the inner shroud 60i, the outer shroud 60o is configured to include the outer shroud body (shroud body) 61o and the impingement plate 81 accommodated inside the outer shroud body 61o and having the plurality of through-holes 82a.

The outer shroud body 61o is configured to include the bottom plate 64 forming the inner surface 64i of the outer shroud body 61o described above, the peripheral wall 65o disposed around the bottom plate 64, the partition rib 60r that partitions the space (cavity 67) inside the outer shroud body 61o, and the shelf 71 (71o) that supports the impingement plate 81. The peripheral wall 65o includes the front peripheral wall 62f and the rear peripheral wall 62b which face each other in the axial direction Da, and the pressure-side peripheral wall 63p and the suction-side peripheral wall 63n which face each other in the circumferential direction Dc. The peripheral wall 65o is disposed around the bottom plate 64, thereby forming the outer shroud body 61o. The recessed portion 66 recessed to the radial inner side Dri from the counter-flow path side is formed inside the outer shroud body 61o. An end surface on the upstream side Dau of the front peripheral wall 62f forms the front end surface 62fa. In addition, an end surface on the downstream side Dad of the rear peripheral wall 62b forms the rear end surface 62ba. In addition, the bottom plate 64 of the outer shroud body 61o includes the gas pass surface 64p facing the radial inner side Dri, and the inner surface (counter-flow path surface) 64i facing the radial outer side Dro which is the counter-flow path side opposite to the gas pass surface 64p.

The pressure-side peripheral wall 63p located on the circumferential pressure-side Dcp in a pair of circumferential end portions 63 forms the pressure-side end surface 63pa. The suction-side peripheral wall 63n located on the circumferential suction-side Dcn in the pair of circumferential end portions 63 forms the suction-side end surface 63na. In the outer shroud 60o described as an example in the present embodiment, similar to the inner shroud 60i, the front peripheral wall 62f and the rear peripheral wall 62b are substantially parallel to each other, and the pressure-side peripheral wall 63p and the suction-side peripheral wall 63n are substantially parallel to each other. Therefore, when viewed in the radial direction Dr, the outer shroud body 61o has a parallel quadrilateral shape.

The pressure-side peripheral wall 63p of the outer shroud 60o of one of the two stator blades 50 adjacent to each other in the circumferential direction Dc is disposed with a gap in the circumferential direction Dc on the suction side peripheral wall 63n of the outer shroud 60o of the other stator blade 50.

As described above, the peripheral wall 65o includes the front peripheral wall 62f and the rear peripheral wall 62b which face each other in the axial direction Da, and the pressure-side peripheral wall 63p and the suction-side peripheral wall 63n which face each other in the circumferential direction Dc.

The pressure-side peripheral wall 63p forms a portion located on the circumferential pressure-side Dcp on the peripheral wall 65o, and the suction-side peripheral wall 63n forms a portion located on the circumferential suction-side Dcn on the peripheral wall 65o.

Both the front peripheral wall 62f and the rear peripheral wall 62b protrude to the radial outer side Dro from the pressure-side peripheral wall 63p and to the suction-side peripheral wall 63n with respect to the outer shroud body 61o.

Here, a concept of the thermal stress acting on the outer shroud 60o will be described below. As described above, the deformation on the hook 69 side is restricted by the influence of the thermal elongation difference in the fitting portion 69a between the hook 69 of the outer shroud 60o and the thermal barrier ring 45c, and the thermal stress is generated between the suction-side end surface 63na and the pressure-side end surface 63pa in the circumferential direction of the rear peripheral wall 62b of the outer shroud 60o. In addition, the rear peripheral wall 62b of the outer shroud 60o tends to be elongated in the circumferential direction Dc due to the heat input from the combustion gas. However, the thermal elongation is restricted by the partition rib 60r that joins the blade body end portion 51r of the blade body 51 and the inner wall surface 65a of the rear peripheral wall 62b, and the thermal stress acts cumulatively in the circumferential direction Dc of the rear peripheral wall 62b.

In order to reduce the thermal stress acting on the outer shroud 60o, in the outer shroud 60o, the trailing edge end portion passage 80 and the trailing edge purge cooling hole 91 (second purge cooling hole 91o) are disposed on the rear peripheral wall 62b. Furthermore, in the outer shroud 60o, the shelf 71 is partially disposed along the peripheral wall 65o, and the region (portion having no shelf) 73 where the shelf 71 is not formed is disposed in a region where the thermal stress is high. In this manner, the thermal strain of the outer shroud 60o is suppressed, and reduced thermal stress is achieved.

As illustrated in FIG. 10, in a case of the outer shroud 60o, as described above, the plurality of trailing edge end portion passages 80 are formed on the rear peripheral wall 62b disposed on the trailing edge portion 53 side of the outer shroud 60o. The plurality of trailing edge end portion passages 80 are arrayed over the entire width from the suction-side end surface 63na to the pressure-side end surface 63pa. In addition, on the rear peripheral wall 62b, in order to improve the cooling on the gas pass surface 64p side where the trailing edge circumferential passages 79 are arrayed, the plurality of trailing edge purge cooling holes 91 (second purge cooling holes 91o) described above are cumulatively arrayed in the radial direction Dr over the entire width from the suction-side end surface 63na to the pressure-side end surface 63pa of the rear peripheral wall 62b.

Therefore, as illustrated in FIG. 10, the peripheral wall 65c having the region 73 where the shelf 71 is not formed is disposed between a shelf 71oc formed to include the third corner C3 and the fourth corner C4 while the partition rib 60r (second partition rib 60rb) is interposed therebetween, in the region where the thermal stress is high, on the inner wall surface 65a of the rear peripheral wall 62b, and the thermal stress of the rear peripheral wall 62b is reduced.

On the other hand, as illustrated in FIG. 10, the front peripheral wall 62f on the leading edge portion 52 side of the outer shroud 60o is hardly restricted from the gas turbine casing 15 side, compared to the rear peripheral wall 62b of the outer shroud 60o. In addition, as described above, the thermal stress is generated on the front peripheral wall 62f due to the restriction of the partition rib 60r (first partition rib 60rf) that joins the blade body end portion 51r of the leading edge portion 52 of the blade body 51 and the inner wall surface 65a of the front peripheral wall 62f. However, a range where the thermal stress is generated is relatively smaller, compared to the rear peripheral wall 62b.

<<Configuration of Partition Rib of Outer Shroud>>

The plurality of partition ribs 60r are formed in the outer shroud 60o. The partition rib 60r formed on the outer shroud 60o has the same structure as the partition rib 60r formed in the inner shroud 60i, and protrudes to the radial outer side Dro from the inner surface 64i of the outer shroud body 61c. Similar to the inner shroud 60i, five partition ribs 60r are formed in the outer shroud 60o of the present embodiment. The space (cavity 67) which is the recessed portion 66 of the outer shroud 60o forms the cavity 67 partitioned into the plurality of spaces in such a manner that the recessed portion 66 is partitioned by disposing the plurality of partition ribs 60r between the blade body end portion 51r and the peripheral wall 65o. In addition, the height from the inner surface 61i of the outer shroud 60o of the blade body end portion 51r, which is an end portion on the radial outer side Dro and the radial inner side Dri of the blade body 51, is the same height as the partition rib 60r. However, the height may be changed depending on a shape of the shroud.

Specifically, the partition ribs 60r of the outer shroud 60o are provided one by one between the blade body end portion 51r of the leading edge portion 52 on the most upstream side Dau of the blade body 51 and the inner wall surface 65a of the front peripheral wall 62f, between the trailing edge portion 53 on the most downstream side Dad of the blade body 51 and the inner wall surface 65a of the rear peripheral wall 62b, and between the suction-side surface 54 of the blade body 51 and the inner wall surface 65a of the suction-side peripheral wall 63n. Furthermore, two partition ribs 60r of the outer shroud 60c are provided at an interval in the axial direction Da between the blade body end portion 51r of the pressure-side surface 55 of the blade body 51 and the inner wall surface 65a of the pressure-side peripheral wall 63p of the peripheral wall 65o. The number or the disposition of the partition ribs 60r formed in the outer shroud 60o is an example, and is not limited to the above-described configuration. The disposition of the partition ribs 60r is different from that of the inner shroud 60i. However, the shape or the structure is formed by using substantially the same concept.

<<Range for Disposing Shelf of Outer Shroud>>

As illustrated in FIG. 10, similar to the peripheral wall 65i of the inner shroud 60i described above, the peripheral wall 65o of the outer shroud 60o has the first corner C1, the second corner C2, the third corner C3, and the fourth corner C4 which are the four corners of the inner wall surface 65a. The first corner C1 is formed by the inner wall surface 65a of the suction-side peripheral wall 63n and by the inner wall surface 65a of the front peripheral wall 62f. The second corner C2 is formed by the inner wall surface 65a of the pressure-side peripheral wall 63p and by the inner wall surface 65a of the front peripheral wall 62t. The third corner C3 is formed by the inner wall surface 65a of the suction-side peripheral wall 63n and by the inner wall surface 65a of the rear peripheral wall 62b. The fourth corner C4 is formed by the inner wall surface 65a of the pressure-side peripheral wall 63p and by the inner wall surface 65a of the rear peripheral wall 62b. In the outer shroud 60o in the present embodiment, the shelves 71 are formed in the first corner C1, the second corner C2, and the third corner C3, and the shelf 71 is not disposed in the fourth corner C4.

Meanwhile, as described above, the rear peripheral wall 62b and the front peripheral wall 62f tend to be elongated in the circumferential direction Dc due to the heat input from the combustion gas. However, the thermal elongation is restricted by the partition ribs 60r (first partition rib 60rf, second partition rib 60rb) that respectively join the blade body end portion 51r of the blade body 51, and the inner wall surface 65a of the rear peripheral wall 62b and the inner wall surface 65a of the front peripheral wall 62f. Therefore, the thermal stress partially high in the circumferential direction Dc acts on the rear peripheral wall 62b and the front peripheral wall 62f around the position Pc of the joining portion joined to the partition ribs 60r (first partition rib 60rf, second partition rib 60rb).

As illustrated in FIG. 10, in a case of the rear peripheral wall 62b of the outer shroud 60o, only the shelf 71oc including the third corner C3 and extending to the circumferential pressure-side Dcp is disposed on the inner wall surface 65a of the rear peripheral wall 62b. That is, only the partition rib 60r (second partition rib 60rb) is disposed between the end portion on the circumferential pressure-side Dcp of the shelf 71oc and the fourth corner C4, and the region 73 where the shelf 71 is not formed is disposed. Meanwhile, the position Pc in the circumferential direction Dc of the second partition rib 60rb is closer to the pressure-side end surface 63pa side than a center position in the circumferential direction Dc of the width from the auction-side end surface 63na to the pressure-side end surface 63pa of the outer shroud body 61o. The thermal stress acting on the rear peripheral wall 62b is the highest in the vicinity of the position Pc of the second partition rib 60rb, and the thermal stress gradually decreases in a direction toward the circumferential suction-side Dcn and in a direction toward the circumferential pressure-side Dcp. In a case of the rear peripheral wall 62b of the outer shroud 60o, the length of the region 73 where the shelf 71 is not formed between the position Pc of the second partition rib 60rb and the end portion on the circumferential pressure-side Dcp of the shelf 71oc is longer than the length of the region 73 where the shelf 71 is not formed between the position Pc of the second partition rib 60rb and the fourth corner C4.

In a case of the front peripheral wall 62f, the concept of the thermal stress acting on the front peripheral wall 62f is the same as that of the inner shroud 60i. In a case of the front peripheral wall 62f, since the heat input from the combustion gas is small, there is less thermal stress generated on the front peripheral wall 62f. A case of the front peripheral wall 62f does not include a cooling structure such as the trailing edge end portion passage 80 and the trailing edge purge cooling hole 91. Similar to the rear peripheral wall 62b, a shelf 71oa including the first corner C1 and extending to the circumferential pressure-side Dcp and a shelf 71ob including the second corner C2 and extending to the circumferential suction-side Dcn are disposed on the inner wall surface 65a of the front peripheral wall 62f, and the first partition rib 60rf interposed from both sides in the circumferential direction Dc by the region 73 where the shelf 71 is not formed is disposed between the shelf 71oa and the shelf 71ob.

Since the regions 73 where the shelves 71 are not formed are disposed on both sides in the circumferential direction Dc while the first partition rib 60rf is interposed therebetween, the thermal stress generated on the front peripheral wall 62f is reduced.

The concept of disposing the shelves 71 on the suction-side peripheral wall 63n and on the pressure-side peripheral wall 63p is the same as that of the inner shroud 60i.

<<Configuration Around Shelf of Outer Shroud>>

As illustrated in FIGS. 10 and 11, similar to the inner shroud 60i, the shelf 71o that supports the impingement plate 81 is provided in the outer shroud 60o. The shelf 71o protrudes to the radial outer side Dro from the inner surface 64i of the bottom plate 64 of the outer shroud body 61o along the inner wall surface 65a of the peripheral wall 65o. That is, the shelf 71o protrudes to the counter-flow path side (radial outer side Dro) opposite to the gas pass surface 54p in the radial direction Dr with reference to the inner surface 64i of the bottom plate 64 of the outer shroud body 61o. The shelf 71o has the support surface 72 facing the counter-flow path side, which is the radial outer side Dro side with respect to the gas pass surface 64p serving as the flow path side, and supports the impingement plate 81.

As illustrated in FIG. 11, the support surface 72 of the shelf 71o provided in the outer shroud 60o is located on a side closer to the inner surface 64i of the bottom plate 64 of the outer shroud body 61o than the end portion 65t of the peripheral wall 65o in the radial direction Dr. In addition, the support surface 72 of the shelf 710 of the outer shroud 60o is located on the radial outer side Dro from a surface facing the radial outer side Dro of the partition rib 60r described above in the radial direction Dr. In other words, the height of the shelf 71o with reference to the inner surface 64i of the outer shroud body 61o in the radial direction Dr is lower than the height of the peripheral wall 65o with reference to the same inner surface 64i. In addition, in the present embodiment, the thickness of the shelf 71o of the outer shroud 60o in a direction protruding to the blade body end portion 51r side from the inner wall surface 65a of the peripheral wall 65o is thinner than the thickness of the peripheral wall 65o in the same direction as the direction of the thickness of the shelf 710.

As illustrated in FIG. 11, the surface 65fa facing the radial outer side Dro of the suction-side peripheral wall 63v and of the pressure-side peripheral wall 63p is closer to the inner surface 64i of the bottom plate 64 than the position of the surface 65ta facing the radial outer side Dro of the end portion 65t of the front peripheral wall 62f and of the rear peripheral wall 62b, and is formed at substantially the same height as the position of the support surface 72 of the shelf 71o.

<<Configuration of Impingement Plate of Outer Shroud>>

As illustrated in FIG. 11, similar to the inner shroud 60i, the impingement plate 81 is attached to the outer shroud 60o. The impingement plate 81 partitions the space inside the recessed portion 66 of the outer shroud 60o into a region on the radial outer side Dro and the cavity 67, which a region on the radial inner side Dri. A plurality of through-holes 82a penetrating in the radial direction Dr are formed in the impingement plate 81. A portion of the cooling air Ac supplied to the recessed portion 66 of the stator blade 50 flows into the cavity 67 via the through-hole 82a formed in the main body portion 82 of the impingement plate 81. Structural details of the impingement plate 81 of the outer shroud 60o are the same as those of the impingement plate 81 of the inner shroud 60i.

As illustrated in FIGS. 6 to 9, the impingement plate 81 attached to the outer shroud 60c includes the main body portion 82 having the plurality of through-holes 82a, the strain absorber 83 that absorbs the thermal strain of the main body portion 82, and the fixing portion 84 that fixes the main body portion 82 to the shroud 60. The main body portion 82 is a member including the plurality of through-holes 82a and extending to the inner wall surface 65a of the peripheral wall 65o in parallel to the inner surface 64l of the bottom plate 64 of the outer shroud body 61o.

The structure of the strain absorber 83 and the fixing portion 84 is the same as that in a case of the inner shroud 60i. In addition, the structure for fixing the impingement plate 81 to the blade body 51 is the same as that in a case of the inner shroud 60i.

Similar to the inner shroud body 61i, the plurality of trailing edge purge cooling holes 91 (second purge cooling holes 51o) are formed in the outer shroud body 61o of the outer shroud 60o. One end of the plurality of second purge cooling holes 91o is open to the inner surface 64i of the outer shroud body 61o on a side closer to the rear peripheral wall 62b on the downstream side Dad than the blade body 51, which is the trailing edge portion 53 side on the Dad downstream side Dad from the blade body 51. In addition, the other end of the plurality of second purge cooling holes 91o is open to discharge openings 91oa formed in the gas pass surface 64p. The plurality of second purge cooling holes 91o are set over substantially the entire width from the suction-side end surface 63na to the pressure-side end surface 63pa, unlike the first purge cooling holes 91i provided in the inner shroud 60i. The reason is that the outer shroud 60o has higher thermal stress on the rear peripheral wall 62b, compared to the inner shroud 60i. In a case of the outer shroud 60o, on the upstream side Dau on the entire surface in the circumferential direction Dc of the rear peripheral wall 62b, a region on the upstream side Dau is supplementarily cooled from the trailing edge circumferential passage 79 of the rear peripheral wall 62b. That is, cooling capacity of the trailing edge end portion passage 80 is supplemented by providing the plurality of second purge cooling holes 91o as described above.

In order to cool the rear peripheral wall 62b of the outer shroud 60o, a cooling structure formed from the trailing edge end portion passage 80, the trailing edge circumferential passage 79, the suction-side passage 78n, and the pressure-side passage 78p is applied in the same manner as that in a case of the inner shroud 60i.

Operational Effect of Embodiment

The stator blade 50 of the above-described embodiment includes at least the blade body 51 disposed in the combustion gas flow path 49 through which the combustion gas flows, and the inner shroud 60i and the outer shroud 60o which include the bottom plate 64 defining a portion of the combustion gas flow path 49. The inner shroud 60i and the outer shroud 60o are formed to include the inner shroud body 61i and the outer shroud body 61o which have the gas pass surface 64p facing the combustion gas flow path 49 of the bottom plate 64, and the inner surface 64i facing the counter-flow path side opposite to the gas pass surface 64p; the peripheral walls 65i and 65o protruding toward the counter-flow path side from the peripheral edge of the inner surface 64i of the inner shroud body 61i and the outer shroud body 61o; the impingement plate 81 attached to the inner shroud body 61i and to the outer shroud body 61o, having the plurality of through-holes 82a, and forming the cavity 67 which is the space between the inner surface 64i of the bottom plate 64 and the inner wall surface 65a of the peripheral walls 65i and 65o; the shelves 71i and 71o formed along the inner wall surface 65a of the peripheral walls 65i and 65o, protruding to the counter-flow path side from the inner surface 64i of the bottom plate 64, and supporting the impingement plate 81; and at least one or more partition ribs 60r protruding to the counter-flow path side from the bottom plate 64, and joining the blade body 51 and the peripheral walls 65i and 65o having the region 73 where the shelf 71 is not formed. The impingement plate 81 forms the cavity 67 which is the space between the inner surface 64i of the bottom plate 64 and the inner wall surface 65a of the peripheral walls 65i and 65o.

According to the configuration of the stator blade 50 of the above-described embodiment, during a normal operation of the gas turbine 10, in some cases, high thermal stress may be locally generated on the rear peripheral wall 62b and the front peripheral wall 62f, due to a thermal elongation difference between the blade body 51 forming the stator blade and the rear peripheral wall 62b and the front peripheral wall 62f which are connected via the partition ribs 60r (first partition rib 60rf, second partition rib 60rb). In addition, in some cases, the thermal stress may be generated particularly on the rear peripheral wall 62b, due to the thermal elongation difference between gas turbine components. As means for reducing the thermal stress, as described below, the region (portion having no shelf) 73 where the shelf 71 is not formed is disposed on the inner wall surface 65a of the peripheral walls 65i and 65o. In this manner, both problems are solved so that the thermal strain or the thermal deformation of the shroud is suppressed, and the thermal stress generated around the front peripheral wall 62f or the rear peripheral wall 62b is reduced.

That is, in the inner shroud 60i and the outer shroud 60o, the shelves 71i and 71o are not provided in the portion where the partition rib 60r is joined to the peripheral walls 65i and 65o, and the partition rib 60r is directly joined to the inner wall surfaces 65a of the peripheral walls 65i and 65o. Therefore, rigidity of the shroud 60 can be reduced.

Therefore, it is possible to suppress the thermal stress generation in the portion (position Pc) where the partition rib 60r reaches the peripheral walls 65i and 65o by extending from the blade body end portion 51r.

In the stator blade 50 of the above-described embodiment, the blade body 51 has the leading edge portion 52 located on the upstream side Dau of the combustion gas flow in the combustion gas flow path 49, the trailing edge portion 53 located on the downstream side Dad of the combust ion gas flow, and the pressure-side surface 55 and the suction-side surface 54 which connect the leading edge portion 52 and the trailing edge portion 53 and face sides opposite to each other in the circumferential direction Dc. The shelves 71i and 71o are formed along the inner wall surface 65a of the peripheral walls 65i and 65o. The peripheral walls 65i and 65o are formed to include the front peripheral wall 62f facing the upstream side Dau and located on the upstream side Dau from the blade body 51, the rear peripheral wall 62b facing the downstream side Dad and located on the downstream side Dad from the blade body 51, the pressure-side peripheral wall 63p connecting the front peripheral wall 62f and the rear peripheral wall 62b and located on a side close to the pressure-side surface 55, and the suction-side peripheral wall 63n connecting the front peripheral wall 62f and the rear peripheral wall 62b and located on a side close to the suction-side surface 54. The shelves 71i and 71o are respectively formed in the third corner C3 formed by the inner wall surface 65a of the suction-side peripheral wall 63n and by the inner wall surface 65a of the rear peripheral wall 62b, and the first corner C1 formed by the inner wall surface 65a of the suction-side peripheral wall 63n and by the inner wall surface 65a of the front peripheral wall 62f. In addition, in the stator blade 50 of the above-described embodiment, the shelves 71i and 710 are formed to include the inner wall surface 65a of the pressure-side peripheral wall 63p and the second corner C2 formed by the inner wall surface 65a of the front peripheral wall 62f.

In the stator blade 50 of the above-described embodiment, the inner shroud 60i and the outer shroud 60o include at least one of the first partition rib 60rf serving as the partition rib 60r that joins the peripheral walls 65i and 65c and the blade body end portion 51r on the leading edge side of the blade body 51, and the second partition rib 60rb serving as the partition rib 60r that joins the peripheral walls 65i and 65o and the blade body end portion 51r on the trailing edge side of the blade body 51. The first partition rib 60rf has a first rib cooling hole 92fa in which one end is open to the inner wall surface of the first partition rib 60rf and the other end is open to the gas pass surface 64p of the bottom plate 64, and which penetrates the first partition rib 60rf. The second partition rib 60rb has a second rib cooling hole 92ba in which one end is open to the inner wall surface of the second partition rib 60rb and the other end is open to the gas pas surface 64p of the bottom plate 64, and which penetrates the second partition rib 60rb.

In the stator blade 50 of the above-described embodiment, the impingement plate 81 includes the main body portion 82 extending in parallel to the inner surface 64i of the inner shroud body 61i and of the outer shroud body 61o, and the first bent portion 83a and the second bent portion 33b in both ends, and includes the strain absorber 83 extending in the radial direction with a predetermined inclination with respect to the main body portion 82 while one end is connected to the main body portion 82, and the fixing portion 84 connected to the second bent portion 83b formed in the other end of the strain absorber 83. The fixing portion 84 is fixed to any one of the surface 65fa facing the counter-flow path side on the peripheral walls 65i and 65o, the support surface 72 facing the counter-flow path side in the shelf 71, and the region 73 where the shelf 71 is not provided on the inner wall surface 65a of the peripheral walls 65i and 65o.

According to the configuration or the stator blade 50 of the above-described embodiment, when the impingement plate 81 is welded to the inner shroud 60i and the outer shroud 60o, even in a case where the impingement plate 81 is thermally elongated due to the heat input caused by welding, the thermal elongation can be absorbed by elastic deformation of the strain absorber 83. Therefore, it is possible to reduce the probability that the strain caused by the welding may be generated in the main body portion 82 of the impingement plate 81.

In the stator blade 50 of the above-described embodiment, the inner shroud body 61i and the outer shroud body 61o include the plurality of trailing edge purge cooling holes 91 open to the inner surface 64i on the counter-flow path side closer to the rear peripheral wall 62b than the blade body 51 and extending toward the downstream side Dad. The plurality of trailing edge purge cooling holes 91 are formed in parallel in the circumferential direction of the rear peripheral wall 62b, one end is open to the inner surface 64i of the bottom plate 64 in which the cavity 67 is formed, and the other end is open to the discharge opening 91oa formed on the gas pass surface 64p. The rear peripheral wall 62b in which the trailing edge purge cooling holes 91 are disposed includes the region where the shelf 71 is not formed.

According to the stator blade 50 of the above-described embodiment, a temperature rise of the rear peripheral wall 62b in a range where the trailing edge purge cooling holes 91 are disposed is suppressed by the cooling air Ac passing through the trailing edge purge cooling holes 91. Therefore, since the region 73 where the shelf 71 is not formed is included on the rear peripheral wall 62b of the range, the thermal stress can be reduced in the region where the temperature rise is suppressed.

In the stator blade 50 of the above-described embodiment, the second partition rib 60rb is disposed in the region 73 where the shelf 71 of the rear peripheral wall 62b on which the trailing edge purge cooling holes 91 are disposed is not formed.

According to the stator blade 50, the thermal stress can be reduced by connecting the second partition rib 60rb to the region 73 of the rear peripheral wall 62b where the trailing edge purge cooling holes 91 are disposed and the shelf 71 is not formed.

In the stator blade 50 of the above-described embodiment, the shelf 71i of the inner shroud body 61i is formed to further include the fourth corner C4 formed by the inner wall surface 65a of the pressure-side peripheral wall 63p and by the inner wall surface 65a of the rear peripheral wall 62b.

According to the stator blade 50, the shelf 71i holds the rigidity of the inner shroud body 61i in the fourth corner C4, and serves as the support surface for the impingement plate 81. The shelf 71i is used for the support surface 72 of the impingement plate 81. In this manner, the height of the impingement plate from the inner surface 64i can be accurately attached, and proper impingement cooling (collision cooling) can be performed on the bottom plate 64.

In the stator blade 50 of the above-described embodiment, the shelf 71i is formed to include the intermediate shelf 71im disposed between the shelf 71ic extending along the inner wall surface 65a of the rear peripheral wall 62b and including the third corner C3 and the shelf 71id extending along the inner wall surface 65a of the rear peripheral wall 62b and including the fourth corner C4, formed along the inner wall surface 65a of the rear peripheral wall 62b, protruding to the counter-flow path side from the inner surface 64i of the bottom plate 64, and supporting the impingement plate 81. The intermediate shelf 71im is interposed from both sides in the circumferential direction Dc by the region 73 where the shelf 71im is not formed, and the second partition rib 60rb is disposed between the fourth corner C4 and the intermediate shelf 71im.

According to the stator blade 50, the region 73 where the shelf 71 is not formed is provided between the third corner C3 and the fourth corner C4 of the inner shroud body 61i, and the rigidity of the rear peripheral wall 62b is reduced. In this manner, the thermal stress generated on the rear peripheral wall 62b can be reduced. In addition, the impingement plate 81 can be supported by the intermediate shelf 71im, and the impingement plate 81 can be disposed at a proper height.

In the stator blade 50 of the above-described embodiment, the trailing edge purge cooling hole 91 includes the plurality of trailing edge purge cooling holes 91 (first purge cooling holes 91i) disposed between the intermediate shelf 71im and the fourth corner C4 of the inner shroud body 61i while the second partition rib 60rb is interposed therebetween.

According to the stator blade 50, the second partition rib 60rb is connected to the region 73 where the shelf 71 is not formed between the intermediate shelf 71im of the rear peripheral wall 62b and the fourth corner C4. In this manner, the thermal stress of the rear peripheral wall 62b is reduced.

In the stator blade 50 of the above-described embodiment, the shroud body 61 includes the outer shroud body 61o disposed on the radial outer side Dro of the blade body 51, and the trailing edge purge cooling hole 91 includes the plurality of trailing edge purge cooling holes 91 (second purge cooling holes 91o) disposed between the third corner C3 of the outer shroud body 61o and the fourth corner C4 of the outer shroud 60o formed by the inner wall surface 65a of the pressure-side peripheral wall 63p and by the inner wall surface 65a of the rear peripheral wall 62b.

According to the stator blade 50, the temperature rise of the rear peripheral wall 62b can be suppressed by the second purge cooling hole 91o between the third corner C3 and the fourth corner C4 of the outer shroud 60o. Therefore, it is possible to suppress the thermal stress in the region where the temperature rise of the rear peripheral wall 62b is suppressed.

In the stator blade 50 of the above-described embodiment, the inner shroud body 61i and the outer shroud body 61o have the cavity 67 surrounded by the peripheral walls 65i and 65o and having the recessed portion 66 recessed to the gas pass surface 64p side from the counter-flow path side in the radial direction Dr. In addition, the inner shroud body 61i and the outer shroud body 610 have the cooling structure including the trailing edge circumferential passage 79 formed in the rear peripheral wall 63b and extending in the circumferential direction Dc, the suction-side passage 78n formed on the suction-side peripheral wall 63n, having one end open to the cavity 67 and the other end connected to one end portion of the trailing edge circumferential passage 79, the pressure-side passage 78p formed on the pressure-side peripheral wall 63p, having one end open to the cavity 67 and the other end connected to the other end portion of the trailing edge circumferential passage 79, and the trailing edge end portion passage 80 formed in the circumferential direction Dc of the rear peripheral wall 62b, having one end connected to the trailing edge circumferential passage 79 and the other end being open to the rear end surface 62ba on the downstream side Dad of the rear peripheral wall 62b. The discharge opening 91ia of the trailing edge purge cooling hole 91 is formed on the downstream side Dad of a passage center line of the trailing edge circumferential passage 79 extending in the circumferential direction Dc.

Since the above-described cooling structure is provided, convection cooling is performed on the suction-side peripheral wall 63n, the pressure-side peripheral wall 63p, and the rear peripheral wall 62b in which severe thermal stress is generated, and the thermal stress is reduced or the trailing edge portion 53 side of the inner shroud body 61i and of the outer shroud body 61o. In addition, with regard to the cooling air Ac, the cooling air Ac obtained by performing impingement cooling (collision cooling) or the bottom plate 64 heated due to the heat input from the gas pass surface 64p of the inner shroud body 61i and of the outer shroud body 61o is used. Furthermore, according to the above-described cooling structure, the convection cooling is performed on the suction-side peripheral wall 63n, the pressure-side peripheral wall 63p, and the rear peripheral wall 62b by using the cooling air Ac. Therefore, the cooling air is reused, and the amount of the cooling air is reduced.

The gas turbine 10 of the above-described embodiment includes the stator blade 50, the gas turbine rotor 11 rotatable by the combustion gas, and the gas turbine casing (casing) 15 that covers the gas turbine rotor 11. The stator blade 50 is disposed inside the gas turbine casing 15, and is fixed to the gas turbine casing 15.

According to the gas turbine 10 of the above-described embodiment, reliability can be improved by suppressing the generation of the thermal deformation and the thermal stress of the stator blade 50.

<<Seal Groove Structure>>

A seal groove 100 (refer to FIG. 3) is formed on the suction-side peripheral wall 63n of the shroud bodies 61i and 61o of the shroud 60 (inner shroud 60i, outer shroud 60o) and on the outer wall surface 65b of the pressure-side peripheral wall 63p, and a seal member 110 is disposed between the shroud bodies 61i and 61o of the stator blades 50 adjacent to each other via the seal groove 100 in the circumferential direction Dc. Since the seal member 110 is disposed, the cooling air Ac supplied to the shroud bodies 61i and 61o from a gap formed between the outer wall surface 65b of the suction-side peripheral wall 63n or the pressure-side peripheral wall 63p and the outer wall surface 651) of the pressure-side peripheral wall 63p or the suction-side peripheral wall 63n of the stator blades 50 disposed adjacent to each other is suppressed from flowing out to the combustion gas flow path 49.

FIG. 12 is a plan sectional view illustrating a combination of the seal groove 100 and the seal member 110 of the inner shroud 60i. FIG. 13 is a perspective view illustrating a combination of the seal groove and the seal member between the suction-side peripheral wall and the adjacent blade.

FIG. 12 illustrates an example of the inner shroud 60i as an example. The seal groove 100 extending to an end portion 70b on the downstream side Dad from an end portion 70a on the upstream side Dau of the suction-side peripheral wall 63n and the pressure-side peripheral wall 63p is formed on the outer wall surface 65b of the suction-side peripheral wall 63n and the pressure-side peripheral wall 63p of the inner shroud body 61i of the inner shroud 60i. The seal groove 100 (suction-side seal groove 100a, pressure-side seal groove 100b) is recessed to the blade body 51 side in the circumferential direction Dc from the outer wall surface 65b of the suction-side peripheral wall 63n or the pressure-side peripheral wall 63p, and a cross section in the axial direction Da is formed in a rectangular shape. The seal groove 100 is formed at a position facing the seal groove 100 formed in the circumferential direction Dc on the pressure-side peripheral wall 63p of an adjacent blade 50a, which is the stator blade 50 adjacent in the circumferential direction Dc, or on the outer wall surface 65b of the suction side peripheral wall 63n. The seal member 110 (to be described later) is inserted into each of the seal grooves 100 (suction-side seal groove 100a, pressure-side seal groove 100b) formed on both sides facing each other in the circumferential direction Dc.

FIG. 13 is a perspective view illustrating a seal structure in which the seal member 110 and the seal groove 100 are combined with each other. The seal structure illustrated in FIG. 13 is configured to include the suction-side seal groove 100a formed on the suction-side peripheral wall 63n of the shroud body 61i of the inner shroud 60i, the pressure-side seal groove 100b formed on the pressure-side peripheral wall 63p of the adjacent blade 50a adjacent to the suction-side peripheral wall 63n, and the seal member 110 inserted into both sides of the suction-side seal groove 100a and the pressure-side seal groove 100b. The end portion 70a on the upstream side Dau of the suction-side seal groove 100a is closed by a wall portion 101, and the end portion 70b on the downstream side Dad is similarly closed by the wall portion 101. Meanwhile in the circumferential direction Dc, the seal structure has an opening 102b formed on the outer wall surface 65b of the suction side peripheral wall 63n and open to the pressure-side peripheral wall 63p side. In addition, an opening 102a open to the upstream side Dau is formed in the end portion 70a on the upstream side Dau of the pressure-side real groove 100b formed on the pressure-side peripheral wall 63p of the adjacent blade 50a formed to face in the circumferential direction Dc, and is not closed by the wall portion 101. Similar to the suction-side seal groove 100a, the end portion 70b on the downstream side Dad is closed by the wall portion 101 (refer to FIG. 12). Meanwhile, in the circumferential direction Dc, the seal structure has an opening 102b formed on the outer wall surface 65b (refer to FIG. 12) of the pressure-side peripheral wall 63p and open to the suction-side peripheral wall 63n side.

The seal member 110 is formed in a flat thin plate shape extending to be longer in the axial direction Da than the width in the circumferential direction Dc. A suction-side end portion 110a of the seal member 110 is inserted into the suction-side seal groove 100a, and a pressure-side end portion 110b of the seal member 110 is inserted into the pressure-side seal groove 100b. In a state where the seal member 110 is inserted into the seal groove 100 and the adjacent blade 50a is assembled, a slight gap is formed between the seal member 110 and an inner surface 100c of the seal groove 100. Here, the reason for maintaining only a slight gap is to reduce the probability that the cooling air may flow to the combustion gas flow path 49 from the gap formed between the seal member 110 and the seal groove 100, and to achieve the reduced amount of the cooling air.

In addition, on the pressure-side peripheral wall 63p of the shroud body 61i of the inner shroud 60i disposed on a side opposite to the above-described suction-side peripheral wall 63n in the circumferential direction Dc, a seal structure is formed to include a combination of the pressure-side seal groove 100b formed on the outer wall surface 65b of the pressure-side peripheral wall 63p, the suction-side seal groove 100a formed on the suction-side peripheral wall 63n of the adjacent blade 50a adjacent to the pressure-side peripheral wall 63p, and the seal member 110 inserted into both sides of the pressure-side seal groove 100b and the suction-side seal groove 100a. Even in a case of the seal structure of the pressure-side peripheral wall 63p, the same structure as the seal structure of the auction-side peripheral wall 63n can be applied. In a case of this seal structure, the opening 102a is formed only in the end portion 70a on the upstream side Dau of the pressure-side seal groove 100b. The end portion 70b on the downstream side Dad, and the end portion 70a on the upstream side Dau and the end portion 70b on the downstream side Dad of the suction-side seal groove 100a of the adjacent blade 26b are closed by the wall portion 101.

In the above-described seal structure, the opening 102a is formed only in the end portion 70a on the upstream side Dau of the pressure-side seal groove 100b of the adjacent blade 50a adjacent to the suction-side peripheral wall 63n. The end portion 70b on the downstream side Dad, the end portion 70a on the upstream side Dau of the pressure-side seal groove 100b of the adjacent blade 50a, and the end portion 70b on the downstream side Dad of the suction-side seal groove 100a are closed by the wall portion 101. However, a set of the seal structures configured to include the suction-side seal groove 100a, the pressure-side seal groove 100b, and the seal member 110 is not limited to the above-described seal structure, as long as only any one location of the end portions 70a and 70b at four locations such as the end portion 70a on the upstream side Dau and the end portion 70b on the downstream side Dad of the suction-side seal groove 100a, and the end portion 70a on the upstream side Dau and the end portion 70b on the downstream side Dad of the pressure-side seal groove 100b includes the opening 102 in the axial direction, and the other three locations are closed by the wall portions 101.

As described above, in the seal groove 100, the opening 102a may be provided in at least one location of the four end portions 20a and 70b in the axial direction Da of the suction-side seal groove 100a and of the pressure-side seal groove 100b which form one set of the seal structures. However, the openings 102a may be provided in two locations. When the openings 102a are provided in two locations, it is not desirable that the openings 102a are provided in both side end portions 70a on both upstream sides Dau of the suction-side seal groove 100a and the pressure-side seal groove 100b which are located at the same position in the axial direction Da, or in both side end portions 70b on both downstream sides Dad of the pressure-side groove 100b and at the end portion 70b on both sides of both downstream sides Dad of the pressure-side seal groove 100b and the suction-side seal groove 100a, in the end portions 70a and 70b in the axial direction Da of the suction-side seal groove 100a and the pressure-side seal groove 100b. In a case where the end portions 70a and 70b which have the openings 102a as described above are located at the same position in the axial direction Da, when the stator blade 50 and the adjacent blade 50a are assembled, and the suction-side seal groove 100a and the pressure-side seal groove 100b are joined via the outer wall surface 65b, the opening 102a formed in the suction-side seal groove 100a and the opening 102a formed in the pressure-side seal groove 100b are adjacent to each other. Consequently, a large opening is formed in the end portions 70a and 70b on the upstream side Dau or the downstream side Dad. Therefore, there is a possibility that the seal member 110 moves inside the seal groove 100 in the axial direction Da due to vibrations of the gas turbine 10, and the seal member 110 may fall off from an upstream end in the axial direction Da of the seal groove 100.

Therefore, when the two openings 102a are provided in one set of the seal structures, a structure may be adopted as follows. The opening 102a is provided in any one end portion 70a in the axial direction Da of the suction-side seal groove 100a and the pressure-side seal groove 100b, and the opening 102a in the remaining one location is provided in the other end portion 701b.

When the above-described seal structure is applied, the seal member 110 can be easily assembled to the seal groove 100 even in a case where the gap between the seal member 110 and the inner wall of the seal groove 100 is small. That is, in the stator blade 50, the adjacent blade 50a is temporarily placed in the circumferential direction Dc. The seal member 110 is disposed between the adjacent blades 50a, and is assembled in the circumferential direction Dc. However, the gap from the adjacent blade 50a in the circumferential direction Dc is small, and the gap between the inner surface 100c of the seal groove 100 and the inserted seal member 110 is also small. Therefore, during a process of connecting the stator blade 50 and the adjacent blade 50a, it is difficult to set the seal member 110 at an accurate position by inserting the seal member 110 along a shape of the seal groove 100.

However, in a case where the opening 102a is formed in the end portions 70a and 70b in at least one location of the four end portions 70a and 70b in four locations on the upstream side Dau and the downstream side Dad of the suction-side seal groove 100a and the pressure-side seal groove 100b which form the above-described set of the seal grooves 100, when the seal member 110 is set, a degree of freedom is added to a movement width and an alignment adjustment width in the seal groove 100 of the seal member 110 inside the seal groove 100, and the seal member 110 is easily assembled to the seal groove 100.

As described above, the shroud 60 (inner shroud 60i, outer shroud 60o) includes a structure in which the shelf 71 (71i, 71o) is disposed on the inner wall surface 65a of the shroud 60, and the impingement plate 81 is fixed to the shelf 71 by means of welding or the like. Since this structure is provided, a cooling structure for performing impingement cooling on the bottom plate 64 of the shroud 60 is provided, and the shelf 71 is molded integrally with the inner wall surface 65a of the shroud 60. Accordingly, the deformation of the shroud 60 can be suppressed by improving the rigidity of the shroud 60. However, when the shelf 71 is formed on the entire periphery of the inner wall surface 65a of the shroud 60, the thermal stress of a portion of the peripheral wall 65 of the shroud 60 increases. Therefore, it is desirable to prevent the deformation of the shroud 60 and to reduce the thermal stress by partially providing a region where the shelf 21 is not disposed. Since this structure of the shroud 60 is provided, the deformation of the suction-side peripheral wall 63n and the pressure-side peripheral wall 63p of the shroud body 61 is suppressed. Therefore, the deformation is suppressed in the suction-side seal groove 100a and the pressure-side seal groove 100b formed on the suction-side peripheral wall 63n and the pressure-side peripheral wall 63p, and the seal member 110 can be easily assembled.

The above-described seal groove 100 indicates a case of the seal groove 100 formed parallel to the gas turbine rotor 11 of the gas turbine 10 (in other words, parallel to the axis Ar). However, as illustrated in FIG. 14, even when the seal groove 100 is inclined (in other words, even when the seal groove 100 is inclined with respect to the axis Ar), the same seal structure can be applied. When the suction-side peripheral wall 63n or the pressure-side peripheral wall 63p has an inclined shape due to a device connection structure on the upstream side Dau or the downstream side Dad of the stator blade 50, the seal groove 100 has a shape inclined with respect to the axis Ar. The shape inclined with respect to the axis Ar may be either a shape facing the upstream side Dau and inclined outward or inclined inward in a blade height direction (shape inclined in a direction away from the gas pass surface 64p in the blade height direction). That is, FIG. 14 illustrates a structure when viewed in a suction-side direction in the circumferential direction Dc of the outer shroud 60o. However, the suction-side seal groove 100a may have a shape facing the upstream side Dau and inclined outward in the blade height direction. In addition, in a case of the inner shroud 60i (not illustrated), the suction-side seal groove 100a may have a shape facing the upstream side Dau and inclined inward in the blade height direction Dr. The same applies to a case of the pressure-side seal groove 100b.

Another Embodiment

Hitherto, the embodiments of the present disclosure have been described in detail with reference to the drawings. However, specific configurations are not limited to the above-described embodiments, and design changes within the scope not departing from the concept of the present disclosure are also included.

For example, in the above-described embodiment, a case where the shelf 71 is provided in the third corner C3 has been described. However, the shelf 71 in the third corner C3 may be omitted.

In the above-described embodiment, a case where the shelves 71 are formed in an L-shape in the first corner C1, the second corner C2, and the third corner C3 when viewed in the radial direction Dr has been described as an example. However, a shape of the shelf 71 is not limited to the Z-shape. For example, a cutout portion may be partially provided in an intermediate portion of the L-shape of the shelf 71 described as an example in the above-described embodiment, and the shelves 71 may be intermittently formed in a rib-less portion 60n.

APPENDIX

The stator blade 50 and the gas turbine 10 described in the above-described embodiment are understood as follows, for example.

(1) The stator blade 50 according to a first aspect includes at least the blade body 51 disposed in the combustion gas flow path 49 through which the combustion gas flows, and the shrouds 60i and 60o that define a portion of the combustion gas flow path 49. The shrouds 60i and 60o include the gas pass surface 64p facing the combustion gas flow path 49, the shroud body 61i and 61o including at least the bottom plate 64 having the inner surface 64i facing the counter-flow path side opposite to the gas pass surface 64p, and the impingement plate 81 attached to the shroud bodies 61i and 61o and having the plurality of through-holes 82a. The shroud body 61i and 61o is formed to include the bottom plate 64, the peripheral walls 65i and 65o protruding toward the counter-flow path side from the peripheral edge of the inner surface 64i of the shroud bodies 61i and 61o, the shelf 71 formed along the inner wall surface 65a of the peripheral walls 65i and 65o, protruding to the counter-flow path side from the inner surface 64i of the bottom plate 64, and supporting the impingement plate 81, and at least one or more partition ribs 60r protruding to the counter-flow path side from the bottom plate 64, and joining the blade body 51 and the peripheral walls 65i and 65o on which the shelf 71 is not formed. The impingement plate 81 forms the cavity 67 which is a space between the inner surface 64i of the bottom plate 64 and the inner wall surface 65a of the peripheral walls 65i and 65o.

Examples of the shrouds 60i and 60o include the inner shroud 60i and the outer shroud 60o. Examples of the shroud bodies 61i and 61o include the inner shroud body 61i and the outer shroud body 61o. Examples of the counter-flow path side include the radial inner side Dri in a case of the inner shroud 60i and the radial outer side Dro in a case of the outer shroud 600.

In the stator blade 50, the shelf 71 is not provided in the portion where the partition rib 60r is joined to the peripheral walls 65i and 65o in the shrouds 60i and 60o. The partition rib 60r is directly joined to the inner wall surface 65a of the peripheral walls 65i and 65o. Therefore, the rigidity of the shrouds 60i and 60o can be reduced.

Therefore, it is possible to suppress the thermal stress generation in the portion where the partition rib 60r reaches the peripheral walls 65i and 65o.

(2) In the stator blade 50 according to a second aspect which is the stator blade 50 of (1), the blade body 51 includes the leading edge portion 52 located on the upstream side Dau of the combustion gas flow in the combustion gas flow path 49, the trailing edge portion 53 located on the downstream side Dad of the combustion gas flow, and the pressure-side surface 55 and the suction-side surface 54 which connect the leading edge portion 52 and the trailing edge portion 53 and face sides opposite to each other. The shelf 71 is formed along the inner wall surface 65a of the peripheral walls 65i and 65o. The peripheral walls 65i and 65o are formed to include the front peripheral wall 62f facing the upstream side Dau and located on the upstream side Dau of the blade body 51, the rear peripheral wall 62n facing the downstream side Dad and located on the downstream side Dad of the blade body 51, the pressure-side peripheral wall 63p connecting the front peripheral wall 62f and the rear peripheral wall 62b and located on the side close to the pressure-side surface 55, and the suction-side peripheral wall 63n connecting the front peripheral wall 62f and the rear peripheral wall 62b and located on the side close to the suction-side surface 54. The shelf 71 is formed to include the first corner C1 formed by the inner wall surface 65a of the suction-side peripheral wall 63n and by the inner wall surface 65a of the front peripheral wall 62f, the second corner C2 formed by the inner wall surface 65a of the pressure-side peripheral wall 63p and by the inner wall surface 65a of the front peripheral wall 62f, and the third corner C3 formed by the inner wall surface 65a of the suction-side peripheral wall 53n and by the inner wall surface 65a of the rear peripheral wall 62b.

In the stator blade 50, in the shrouds 60i and 60o, the first corner C1 and the second corner C2 on the leading edge portion 52 side at the position away from the fitting portion 69a between the hook 69 and the thermal barrier ring 45c in the axial direction Da are less affected by the thermal stress generated in the fitting portion 69a. Therefore, the rigidity around the first corner C1 and the second corner C2 can be increased by disposing the shelf 71. In addition, the third corner C3 close to the trailing edge portion 53 is a corner on the suction-side away from the blade body 51 and the second partition rib 60rb, and is less affected by the thermal stress than the fourth corner C4. Therefore, the rigidity of the shrouds 60i and 60o can be further increased by providing the shelf 71 in the third corner C3. Therefore, it is possible to suppress the strain of the shrouds 60i and 600 due to the thermal deformation.

(3) In the stator blade 50 according to a third aspect which is the stator blade 50 of (2), the shroud bodies 61i and 61o include at least one of the first partition rib 60rf which is the partition rib joining the peripheral walls 65i and 65o and the blade body end portion on the leading edge side of the blade body 51, and the second partition rib 60rb which is the partition rib joining the peripheral walls 65i and 65o and the blade body end portion on the trailing edge side of the blade body 51. In the first partition rib 60rf, the first rib cooling hole 92fa having one end open to the inner wall surface of the first partition rib 60rf, and the other end open to the gas pass surface 64p of the bottom plate 64, and penetrating the first partition rib 60rf is formed. In the second partition rib 60rb, the second rib cooling hole 92ba having one end open to the inner wall surface of the second partition rib 60rb, and the other end open to the gas pass surface 64p or the bottom plate 64, and penetrating the second partition rib 60rb is formed.

In the stator blade 50, the first partition rib 60rf and the second partition rib 60rb receive the thermal stress due to the thermal elongation difference between the blade body 51 and the front peripheral wall 62f and the rear peripheral wall 62b. However, since the first partition rib 60rf and the second partition rib 60rb are cooled by the first rib cooling hole 92fa and the second rib cooling hole 92ba, the thermal stress is reduced.

(4) In the stator blade 50 according to a fourth aspect which is the stator blade 50 of (2) or (3), the impingement plate 81 includes the main body portion 82 extending parallel to the inner surface 64i of the shroud bodies 61i and 61o, the strain absorber 83 including the bent portions 83a and 83b in both ends, and extending in the radial direction with the predetermined inclination with respect to the main body portion 82 while one end is connected to the main body portion 82, and the fixing portion 84 connected to the bent portion 83b formed in the other end of the strain absorber 83. The fixing portion 84 is fixed to any one of the surface 65fa facing the counter-flow path side on the peripheral walls 65i and 65o, the support surface 72 facing the counter-flow path side in the shelf 21, and the region where the shelf 71 is not provided on the inner wall surfaces 65a of the peripheral walls 65i and 65o.

In the stator blade 50, when the impingement plate 81 in welded to the shrouds 60i and 60o, even if the impingement plate 81 is thermally elongated due to the heat input by welding, this thermal elongation can be absorbed by the elastic deformation of the strain absorber 83. Therefore, it is possible to reduce the probability that the strain caused by the welding may be generated in the main body portion 82 of the impingement plate 81.

(5) In the stator blade 50 according to a fifth aspect which is the stator blade 50 according to any one of (2) to (4), the shroud bodies 61i and 61o include the plurality of trailing edge purge cooling holes 91 open to the inner surface 64i on the side closer to the rear peripheral wall 62b than the blade body 51 and extending toward at least the downstream side Dad from the inner surface 64i side. The plurality of trailing edge purge cooling holes 91 are formed in parallel in the circumferential direction of the rear peripheral wall 62b, having one end open to the cavity 6F and the other end open to the discharge opening formed on the gas pass surface 64p. The rear peripheral wall 62b where the trailing edge purge cooling hole 91 is disposed include the region where the shelf 71 is not formed.

In the stator blade 50, the temperature rise of the rear peripheral wall 62b in the range where the trailing edge purge cooling hole 91 is disposed is suppressed by the cooling air passing through the trailing edge purge cooling hole 91. Therefore, since the rear peripheral wall 62b in the range includes the region where the shelf 71 is not formed, the thermal stress in the region where the temperature rise is suppressed can be reduced.

(6) In the stator blade 50 according to a sixth aspect which is the stator blade 50 of (5), the second partition rib 60rb is disposed in the region where the shelf 71 is not formed on the rear peripheral wall 62b in which the trailing edge purge cooling hole 91 is disposed.

In the stator blade 50, the second partition rib 60rb in Joined to the region of the rear peripheral wall 62b where the trailing edge purge cooling hole 91 is disposed and the shelf 71 is not formed. Therefore, the thermal stress around the joining portion between the second partition rib 60rb and the rear peripheral wall 62b is reduced.

(7) In the stator blade 50 according to a seventh aspect which is the stator blade 50 of (6), the shroud bodies 61i and 61o are inner shroud bodies 61i disposed on the radial inner side Dri of the blade body 51. The shelf 71 is formed to further include the fourth corner C4 formed by the inner wall surface 65a of the pressure-side peripheral wall 63p and by the inner wall surface 65a of the rear peripheral wall 62b.

In the stator blade 50, the rigidity of the inner shroud body 61i in the fourth corner C4 can be improved.

In the stator blade 50 according to an eighth aspect which is the stator blade 50 of (7), the shelf 71 is formed to include the intermediate shelf 71im disposed between the shelf 71ic formed to extend along the inner wall surface 65a of the rear peripheral wall 62b and to include the third corner C3, and the shelf 71id is formed to extend along the inner wall surface 65a of the rear peripheral wall 62b and to include the fourth corner C4, formed along the inner wall surface 65a of the rear peripheral wall 62b, protruding to the counter-flow path side from the inner surface 64i of the bottom plate 64, and supporting the impingement plate 81. The intermediate shelf 71im is interposed from both sides in the circumferential direction Dc by the region where the shelf 71 is not formed. The second partition rib 60rb is disposed between the fourth corner C4 and the intermediate shelf 71im. In the stator blade 50, the impingement plate 81 can be supported by the intermediate shelf 71im between the third corner C3 and the fourth corner C4 of the inner shroud body 61i, and the proper height of the impingement plate 81 can be maintained.

(9) in the stator blade 50 according to a ninth aspect which the stator blade 50 of (8), the trailing edge purge cooling hole 91 includes the plurality of first purge cooling holes 91i disposed between the intermediate shelf 71im and the fourth corner C4 of the inner shroud body 61i while the second partition rib 60rb is interposed therebetween.

In the stator blade 50, the region where the shelf 71 is not formed is provided in the region between the intermediate shelf 71im of the rear peripheral wall 62b and the fourth corner C4 so that the rigidity of the region is reduced and the cooling effect of the first purge cooling hole 91i is achieved. In this manner, the thermal stress of the rear peripheral wall 62b between the intermediate shelf 71im and the fourth corner C4 can be reduced. In addition, since the intermediate shelf 71im is disposed, the impingement plate 81 disposed between the third corner C3 and the second partition rib 60rb can be maintained at a proper height.

(10) In the stator blade 50 according to a tenth aspect which is the stator blade 50 of (5) or (6), the shroud body 61 includes the outer shroud body 61o disposed on the radial outer side Dro of the blade body 51. The trailing edge purge cooling hole 91 includes the plurality of second purge cooling holes 91o disposed between the third corner C3 of the outer shroud body 61o and the fourth corner C4 of the outer shroud body 61c formed by the inner wall surface 65a of the pressure-side peripheral wall 63p and by the inner wall surface 65a of the rear peripheral wall 62b.

In the stator blade 50, the temperature rise of the rear peripheral wall 62b can be suppressed by the second purge cooling hole 91o between the third corner C3 and the fourth corner C4. Therefore, it is possible to suppress the thermal stress generation in the region where the temperature rise of the rear peripheral wall 62b is suppressed.

(11) In the stator blade 50 according to an eleventh aspect which is the stator blade 50 according to any one of (5) to (10), the shroud bodies 61i and 61o include the cavity 67 surrounded by peripheral walls 65i and 65o and having the recessed portion recessed toward the gas pass surface 64p side from the counter-flow path side in the radial direction Dr, the trailing edge circumferential passage 79 formed on the rear peripheral wall 62b and extending in the circumferential direction Dc, the suction-side passage 78n formed on the suction-side peripheral wall 53n, having one end open to the cavity 67 and the other end connected to one end portion of the trailing edge circumferential passage 79, the pressure-side passage 78p formed on the pressure-side peripheral wall 63p, having one end open to the cavity 67 and the other end connected to the other end portion of the trailing edge circumferential passage 79, and the trailing edge end portion passage 80 formed in the circumferential direction Dc of the rear peripheral wall 62b, having one end connected to the trailing edge circumferential passage 79 and the other end open to the rear end surface on the downstream side Dad of the rear peripheral wall 62b, and the discharge opening 91ia of the trailing edge purge cooling hole 91 is formed on the downstream side Dad from the passage center line of the trailing edge circumferential passage 79 extending in the circumferential direction Dc.

In the stator blade 50, the position of the discharge opening 91ia of the trailing edge purge cooling hole 91 is disposed on the downstream side Dad from the trailing edge circumferential passage 79. Therefore, the gas pass surface 64p side of the region between the inner wall surface 65a of the rear peripheral wall 62b and the trailing edge circumferential passage 79 which is the leading edge portion 53 side from the trailing edge circumferential passage 79 is cooled by the trailing edge purge cooling hole 91, and the thermal stress of the rear peripheral wall 62b is further reduced.

(12) In the stator blade 50 according to a twelfth aspect which is the stator blade 50 according to any one of (2) to (11), the pressure-side peripheral wall 63p or the suction-side peripheral wall 63n includes the groove 100 formed on the outer wall surface 65b directed in the circumferential direction, extending to the downstream side from the upstream side in the axial direction, and configured to accommodate the plate-shaped seal member 110.

In the stator blade, the shroud includes the groove 100 configured to accommodate the seal member 110 on the pressure-side peripheral wall 63p or the suction-side peripheral wall 63n. Therefore, a loss of the cooling air flowing into the combustion gas flow path 49 is suppressed.

(13) In the stator blade 50 according to a thirteenth aspect which is the stator blade 50 of (12), the groove 100 is recessed to a blade body side in the circumferential direction from the outer wall surface 65b, and is formed in a rectangular shape when viewed in the axial direction.

At least one end portion among the end portion 70a on the upstream side in the axial direction of the suction-side peripheral wall 63n, the end portion 70b on the downstream side in the axial direction of the suction-side peripheral wall 63n, the end portion 70a on the upstream side in the axial direction of the pressure-side peripheral wall 63p, and the end portion 70b on the downstream side in the axial direction of the pressure-side peripheral wall 63p includes the opening 102a which is open in the axial direction, and the other end portions 70a and 70b which do not include the opening 102a include the wall portion 101 that closes the groove 100 in the axial direction.

In the stator blade, at least one of the end portions 70a and 70b on the upstream side or the downstream side in the axial direction of the suction-side peripheral wall 63n or the pressure-side peripheral wall 63p includes the opening 102a which is not closed by the wall portion 101. Therefore, the seal member 110 can be easily assembled to the groove 130.

(14) In the stator blade 50 according to a fourteenth aspect which is the stator blade 50 of (12) or (13), the groove 100 is recessed to a blade body side in the circumferential direction from the outer wall surface 65b, is formed in a rectangular shape when viewed in the axial direction, and is disposed to face the groove 100 formed on the outer wall surface 65b of the adjacent blade 50a disposed to be adjacent in the circumferential direction. At least one end portion among the end portion 70a on the upstream side in the axial direction of the pressure-side peripheral wall 63p, the end portion 70b on the downstream side in the axial direction of the pressure-side peripheral wall 63p, the end portion 70a on the upstream side in the axial direction of the suction-side peripheral wall 63n of the adjacent blade 50a adjacent to the pressure-side peripheral wall 63p, and the end portion 20b on the downstream side in the axial direction of the suction-side peripheral wall 63n of the adjacent blade 50a, and at least one end portion among the end portion on the upstream side in the axial direction of the suction-side peripheral wall 63n, the end portion on the downstream side in the axial direction of the suction-side peripheral wall 63n, the end portion 70a on the upstream side in the axial direction of the pressure-side peripheral wall 63p of the adjacent blade adjacent to the suction-side peripheral wall 63n, and the end portion 70b on the downstream side in the axial direction of the pressure-side peripheral wall 63p of the adjacent blade 50a adjacent to the suction-side peripheral wall 63n include the opening 102a which is open in the axial direction, and the other end portions 70a and 70b which do not include the opening 102a include the wall portion 101 that closes the groove 100 in the axial direction.

(15) In the stator blade 50 according to a fifteenth aspect which is the stator blade 50 of (12) to (14), the groove 100 is directed toward the downstream side from the upstream side in the axial direction, and is inclined to the counter-flow path side in the blade height direction.

(16) The stator blade 50 according to a sixteenth aspect which is the stator blade 50 according to any one of (5) to (10) includes at least the blade body 51 disposed in the combustion gas flow path 49 through which the combustion gas flows, and the shrouds 60i and 60o that define a portion of the combustion gas flow path 49. The shrouds 60i and 60o include the shroud bodies 61i and 61o including at least the bottom plate 64 having the gas pass surface 64p facing the combustion gas flow path 49 and the inner surface 64i facing the counter-flow path side opposite to the gas pass surface 64p, and the impingement plate 81 attached to the shrouds 60i and 60o and having the plurality of through-holes 82a. The shroud bodies 61i and 61o include the bottom plate 64, the peripheral walls 65i and 65o protruding to the counter-flow path side from the peripheral edge of the inner surface 64i of the shroud bodies 61i and 61o, and the shelf 71 formed to protrude to the counter-flow path side from the inner surfaces 64i along only a portion of the inner wall surface 65a of the peripheral walls 65i and 65o, and Supporting the impingement plate 81. The impingement plate 81 includes the main body portion 82 extending parallel to the inner wall surface 65a of the shroud bodies 61i and 61o, and the bent portions 83a and 83b in both ends, and includes the strain absorber 83, having one end connected to the main body portion 82, having a predetermined inclination with respect to the main body portion 82, and extending in the radial direction, and the fixing portion 84 connected to the bent portion 83b formed in the other end of the strain absorber 83. The fixing portion 84 is fixed to any one of the surface 65fa facing the counter-flow path side on the peripheral walls 65i and 65o, the support surface 72 facing the counter-flow path side in the shelf 71, and the region where the shelf 71 is not provided on the inner wall surface 65a of the peripheral walls 65i and 65o.

In the stator blade 50, when the impingement plate 81 is welded to the shrouds 60i and 60o, even in a case where the impingement plate 81 is thermally elongated due to the heat input by welding, the thermal elongation can be absorbed by the elastic deformation of the strain absorber 62. Therefore, it is possible to reduce the probability that the strain caused by the welding may be generated in the main body portion 82 of the impingement plate 81.

(1) The gas turbine 10 includes the stator blade 50 according to any one of (1) to (16), the rotor 11 rotatable by the combustion gas, and the casing 15. The stator blade 50 is disposed inside the casing 15, and is fixed to the casing 15.

In the gas turbine 10, the reliability can be improved by suppressing the thermal deformation and the thermal stress generation of the stator blade 50.

INDUSTRIAL APPLICABILITY

According to the present disclosure, it is possible to provide the stator blade and the gas turbine which can suppress the thermal stress generation.

REFERENCE SIGNS LIST

• • 10: gas turbine
  • 11: gas turbine rotor (rotor)
  • 14: intermediate casing
  • 15: casing
  • 15: gas turbine casing (casing)
  • 20: compressor
  • 21: compressor rotor
  • 22: rotor shaft
  • 23: rotor blade row
  • 23 a: rotor blade
  • 25: compressor casing
  • 26: stator blade row
  • 26 a: stator blade
  • 30: combustor
  • 40: turbine
  • 41: turbine rotor
  • 42: rotor shaft
  • 43: rotor blade row
  • 43 a: rotor blade
  • 43 p: platform
  • 43 r: blade root
  • 45: turbine casing
  • 45 a: outer casing
  • 45 b: inner casing
  • 45 c: thermal barrier ring
  • 45 p: cooling air passage
  • 46: stator blade row
  • 49: combustion gas flow path
  • 50: stator blade
  • 50 a: adjacent blade
  • 51: blade body
  • 51 r: blade body end portion
  • 52: leading edge portion
  • 53: trailing edge portion
  • 54: suction-side surface
  • 55: pressure-side surface
  • 56: fillet portion
  • 60 i: inner shroud
  • 60 o: outer shroud
  • 60 r: partition rib
  • 60 rf: first partition rib
  • 60 rb: second partition rib
  • 61 i: inner shroud body (shroud body)
  • 61 o: outer shroud body (shroud body)
  • 62 b: rear peripheral wall
  • 62 f: front peripheral wall
  • 63: circumferential end portion
  • 63 n: suction-side peripheral wall
  • 63 p: pressure side peripheral wall
  • 64: bottom plate
  • 64 i: inner surface (counter-flow path surface)
  • 64 p: gas pass surface
  • 65 a: inner wall surface
  • 65 b: outer wall surface
  • 65 fa: surface
  • 65 i, 65o: peripheral wall
  • 65 t: end portion
  • 66: recessed portion
  • 67: cavity
  • 69: hook
  • 69 a: fitting portion
  • 71, 71i, 71o: shelf
  • 71 im: intermediate shelf
  • 72: support surface
  • 75: blade air passage
  • 77: blade surface ejection passage
  • 81: impingement plate
  • 81 a: first edge
  • 81 b: second edge
  • 81 c: third edge
  • 81W: welding portion
  • 82: main body portion
  • 82 a, 82b: through-hole
  • 83: strain absorber
  • 64: fixing portion
  • 90: split ring
  • 91: trailing edge purge cooling hole
  • 100: seal groove (groove)
  • 110: seal member

Claims

1. A stator blade comprising at least: a blade body disposed in a combustion gas flow path through which a combustion gas flows; anda shroud that defines a part of the combustion gas flow path,wherein the shroud includesa shroud body including at least a bottom plate having a gas pass surface facing the combustion gas flow path, andan inner surface facing a counter-flow path side opposite to the gas pass surface, andan impingement plate attached to the shroud body and having a plurality of through-holes,the shroud body is formed to includethe bottom plate,a peripheral wall protruding toward the counter-flow path side from a peripheral edge of the inner surface of the shroud body,a shelf formed along an inner wall surface of the peripheral wall, protruding to the counter-flow path side from the inner surface of the bottom plate, and supporting the impingement plate, andat least one or more partition ribs protruding to the counter-flow path side from the bottom plate, and joining the blade body and the peripheral wall on which the shelf is not formed, andthe impingement plate forms a cavity which is a space between the inner surface of the bottom plate and the inner wall surface of the peripheral wall.

2. The stator blade according to claim 1, wherein the blade body includesa leading edge portion located on an upstream side of a combustion gas flow in the combustion gas flow path,a trailing edge portion located on a downstream side of the combustion gas flow, anda pressure-side surface and a suction-side surface which connect the leading edge portion and the trailing edge portion and face sides opposite to each other,the shelf is formed along the inner wall surface of the peripheral wall,the peripheral wall is formed to includea front peripheral wall facing the upstream side and located on the upstream side of the blade body,a rear peripheral wall facing the downstream side and located on the downstream side of the blade body,a pressure-side peripheral wall connecting the front peripheral wall and the rear peripheral wall and located on a side close to the pressure-side surface, anda suction-side peripheral wall connecting the front peripheral wall and the rear peripheral wall and located on a side close to the suction-side surface, andthe shelf is formed to includea first corner formed by an inner wall surface of the suction-side peripheral wall and by an inner wall surface of the front peripheral wall,a second corner formed by an inner wall surface of the pressure-side peripheral wall and by the inner wall surface of the front peripheral wall, anda third corner formed by the inner wall surface of the suction-side peripheral wall and by an inner wall surface of the rear peripheral wall.

3. The stator blade according to claim 2, wherein the shroud body includes at least one ofa first partition rib which is a partition rib joining the peripheral wall and a blade body end portion on a leading edge side of the blade body, anda second partition rib which is a partition rib joining the peripheral wall and a blade body end portion on a trailing edge side of the blade body,in the first partition rib, a first rib cooling hole having one end open to an inner wall surface of the first partition rib, and the other end open to the gas pass surface of the bottom plate, and penetrating the first partition rib is formed, andin the second partition rib, a second rib cooling hole having one end open to an inner wall surface of the second partition rib, and the other end open to the gas pass surface of the bottom plate, and penetrating the second partition rib is formed.

4. The stator blade according to claim 2, wherein the impingement plate includesa main body portion extending parallel to the inner surface of the shroud body,a strain absorber including bent portions in both ends, and extending in a radial direction with a predetermined inclination with respect to the main body portion while one end is connected to the main body portion, anda fixing portion connected to the bent portion formed in the other end of the strain absorber, andthe fixing portion is fixed to any one of a surface facing the counter-flow path side on the peripheral wall, a support surface facing the counter-flow path side in the shelf, and a region where the shelf is not provided on the inner wall surface of the peripheral wall.

5. The stator blade according to claim 2, wherein the shroud body includes a plurality of trailing edge purge cooling holes open to the inner surface on a side closer to the rear peripheral wall than the blade body and extending toward at least the downstream side from the counter-flow path side,the plurality of trailing edge purge cooling holes are formed in parallel in a circumferential direction of the rear peripheral wall, and have one end open to the cavity and the other end open to a discharge opening formed on the gas pass surface, andthe rear peripheral wall where the trailing edge purge cooling hole is disposed includes a region where the shelf is not formed.

6. The stator blade according to claim 5, wherein the partition rib is disposed in the region where the shelf is not formed on the rear peripheral wall in which the trailing edge purge cooling hole is disposed.

7. The stator blade according to claim 6, wherein the shroud body is an inner shroud body disposed inside the blade body in a radial direction, andthe shelf is formed to further include a fourth corner formed by the inner wall surface of the pressure-side peripheral wall and by the inner wall surface of the rear peripheral wall.

8. The stator blade according to claim 7, wherein the shelf is formed to include an intermediate shelf disposed between the shelf formed to extend along the inner wall surface of the rear peripheral wall and to include the third corner, and the shelf is formed to extend along the inner wall surface of the rear peripheral wall and to include the fourth corner, formed along the inner wall surface of the rear peripheral wall, protruding to the counter-flow path side from the inner surface of the bottom plate, and supporting the impingement plate,the intermediate shelf is interposed from both sides in the circumferential direction by the region where the shelf is not formed, andthe partition rib is disposed between the fourth corner and the intermediate shelf.

9. The stator blade according to claim 8, wherein the trailing edge purge cooling hole includes a plurality of first purge cooling holes disposed between the intermediate shelf and the fourth corner of the inner shroud body while the partition rib is interposed therebetween.

10. The stator blade according to claim 5, wherein the shroud body includes an outer shroud body disposed outside the blade body in a radial direction, andthe trailing edge purge cooling hole includes a plurality of second purge cooling holes disposed between the third corner of the outer shroud body and a fourth corner of the outer shroud body formed by the inner wall surface of the pressure-side peripheral wall and by the inner wall surface of the rear peripheral wall.

11. The stator blade according to claim 5, wherein the shroud body includesa cavity surrounded by the peripheral wall and having a recessed portion recessed toward a gas pass surface side from the counter-flow path side in a radial direction,a trailing edge circumferential passage formed on the rear peripheral wall and extending in the circumferential direction,a suction-side passage formed on the suction-side peripheral wall, and having one end open to the cavity and the other end connected to one end portion of the trailing edge circumferential passage,a pressure-side passage formed on the pressure-side peripheral wall, and having one end open to the cavity and the other end connected to the other end portion of the trailing edge circumferential passage, anda trailing edge end portion passage formed in the circumferential direction of the rear peripheral wall, and having one end connected to the trailing edge circumferential passage and the other end open to a rear end surface on the downstream side in an axial direction of the rear peripheral wall, andthe discharge opening of the trailing edge purge cooling hole is formed on the downstream side in the axial direction from a passage center line of the trailing edge circumferential passage extending in the circumferential direction.

12. The stator blade according to claim 2, wherein the pressure-side peripheral wall or the suction-side peripheral wall includes a groove formed on an outer wall surface directed in a circumferential direction, extending to the downstream side from the upstream side in an axial direction, and configured to accommodate a plate-shaped seal member.

13. The stator blade according to claim 12, wherein the groove is recessed to a blade body side in the circumferential direction from the outer wall surface, and is formed in a rectangular shape when viewed in the axial direction, andat least one end portion among an end portion on the upstream side in the axial direction of the suction-side peripheral wall, an end portion on the downstream side in the axial direction of the suction-side peripheral wall, an end portion on the upstream side in the axial direction of the pressure-side peripheral wall, and an end portion on the downstream side in the axial direction of the pressure-side peripheral wall includes an opening which is open in the axial direction, andthe other end portion which does not include the opening includes a wall portion that closes the groove in the axial direction.

14. The stator blade according to claim 12, wherein the groove is recessed to a blade body side in the circumferential direction from the outer wall surface, is formed in a rectangular shape when viewed in the axial direction, and is disposed to face the groove formed on the outer wall surface of an adjacent blade disposed to be adjacent in the circumferential direction, andat least one end portion among an end portion on the upstream side in the axial direction of the pressure-side peripheral wall, an end portion on the downstream side in the axial direction of the pressure-side peripheral wall, an end portion on the upstream side in the axial direction of the suction-side peripheral wall of the adjacent blade adjacent to the pressure-side peripheral wall, and an end portion on the downstream side in the axial direction of the suction-side peripheral wall of the adjacent blade, and at least one end portion among an end portion on the upstream side in the axial direction of the suction-side peripheral wall, an end portion on the downstream side in the axial direction of the suction-side peripheral wall, an end portion on the upstream side in the axial direction of the pressure-side peripheral wall of the adjacent blade adjacent to the suction-side peripheral wall, and an end portion on the downstream side in the axial direction of the pressure-side peripheral wall of the adjacent blade adjacent to the suction-side peripheral wall include an opening which is open in the axial direction, andthe other end portion which does not include the opening includes a wall portion that closes the groove in the axial direction.

15. The stator blade according to claim 12, wherein the groove is directed toward the downstream side from the upstream side in the axial direction, and is inclined to the counter-flow path side in a blade height direction.

16. A gas turbine comprising: the stator blade according to claim 1;a rotor rotatable by the combustion gas; anda casing that covers the rotor,wherein the stator blade is disposed inside the casing, and is fixed to the casing.