The present invention relates to a gas turbine engine having an outlet guide vane located downstream of a compressor.
A gas turbine engine which uses an axial (axial-flow) compressor includes a diffuser located downstream of a compressor. An outlet guide vane is provided at an inlet of the diffuser. When the outlet guide vane is supported on the outer wall surface of the diffuser, a gap is often provided between the outlet guide vane and the inner wall surface of the diffuser. To prevent the thermally expanded outlet guide vane from contacting the inner wall surface of the diffuser, the gap is provided between the outlet guide vane and the inner wall surface of the diffuser. In this structure, air leaks through the gap and a pressure loss increases, which may reduce the compressor efficiency. To solve this problem, there is a gas turbine in which a recess is formed in the inner wall surface of the diffuser and the front edge of the outlet guide vane is inserted into the recess to prevent air leakage (e.g., see FIG. 8 in Patent Literature 1).
Patent Literature 1: Japanese Laid-Open Patent Application Publication No. 2000-314397
However, even when the front edge of the outlet guide vane is inserted into the recess of the diffuser, the vibration is easily generated at the vane because it is supported only on the outer wall surface side of the diffuser. This vibration sometimes causes the front edge of the vane to contact the recess, which may a wear-out of the vane.
Therefore, an objective of the present invention is to provide a gas turbine engine which is capable of suppressing a vibration of an outlet guide vane while permitting the vane to be thermally expanded.
According to the aspect of the present invention, a gas turbine engine comprises an outlet guide vane downstream of a compressor; an outer casing supporting a radially outward part of the outlet guide vane; and an inner diffuser supporting a radially inward part of the outlet guide vane; wherein the outlet guide vane has: a radially inward inner flange; a projecting part projecting radially inward from the inner flange; and an engagement part protruding to one side in an axial direction from a front edge of the projecting part; and wherein the inner diffuser has a smaller-diameter part, of which an outer diameter is smaller than that of an adjacent part; the inner diffuser is provided with an engagement groove extending to the one side in the axial direction of an outer surface of the smaller-diameter part or a region in the vicinity of the outer surface of the smaller-diameter part; and the engagement part is inserted into the groove with a gap between the part and the groove.
In accordance with this configuration, since the outlet guide vane is supported at both sides by the inner diffuser and the outer casing, a vibration of the vane can be suppressed. Moreover, because the engagement part is inserted into the groove with the gap, thermal expansion of the vane can be permitted.
In accordance with the gas turbine engine of the present invention, the vibration of the outlet guide vane can be suppressed while permitting thermal expansion of the vane.
A preferred embodiment of the present invention is described as follows with reference to the drawings.
<Outline of Gas Turbine>
First of all, the air flow and major components of a gas turbine engine (referred to as “gas turbine”) are described with reference to
Initially, air IA passed through an air-intake collector 19 is compressed in a compressor 3. The compressor 3 of the present embodiment is an axial (axial-flow) compressor and includes a number of stages of rotor blades 13 and those of stages of stator vanes 17. The respective stages of rotor blades 13 are mounted to the outer peripheral surface of a compressor rotor 11A and axially arranged at predetermined intervals r. Each stage of stator vane 17 is located downstream of the corresponding stage of rotor blade 13, and mounted to an outer casing 15. As described later, a last-stage stator vane 30 is mounted by a different support structure compared to other stator vanes 17.
Then, compressed air CA which has been compressed by the compressor 3 flows through a diffuser 23 located downstream of the compressor 3 via an outlet guide vane 40. The outlet guide vane 40 is located downstream of the last-stage stator vane 30 of the compressor 3 and neighborhood of the vane 30 (see
Then, the compressed air CA which has passed through the diffuser 23 is guided to a combustor 5. In the combustor 5, the compressed air CA and a fuel F injected into the combustor 5 are mixed and combusted. Thus, high-temperature and high-pressure combustion gas G are generated.
After that, the combustion gas G generated in the combustor 5 flows through a turbine nozzle (first-stage stator vane) 25 and drives the turbine 7. A high-pressure turbine rotor 11B is rotatably supported by bearings 24A and 24B. A low-pressure turbine rotor 11C is supported by bearings 24C via a turbine shaft 11D coupled to the rear part of the rotor 11C. The rotor 11B is coupled to the compressor rotor 11A to drive the rotor 11A.
<Configuration of Outlet Guide Vane>
Next, the configuration of the outlet guide vane 40 of the present embodiment is illustrated in
The configuration of inner flange 44 is as follows. As shown in
<Configuration of Stator Vane>
Next, the configuration of the last-stage stator vane (referred to as “stator vane”) 30 of the compressor 3 of the present embodiment is illustrated in
The configuration of an inner flange 34 is shown below. The foreside of an inner flange 34 has an engagement part 36. The engagement part 36 includes a projecting part 36a projecting radially inward from the front end of the inner flange 34, and an engagement part 36b protruding rearward from the projecting part 36a. As shown in
<Support Structure of Guide Vane Piece>
Next, a support structure of the guide vane piece 45 is drawn in
Initially, the support structure in the outer casing 15 is shown below. As shown in
Between each engagement part 43 and the corresponding engagement groove 15b, a proper gap (clearance) is provided in both of the axial and the radial directions. This allows the engagement part 43 to be movable in the axial and the radial directions with respect to the engagement groove 15b. Note that a leaf spring 28 having a circular-arc shape when viewed from the axial direction is inserted between the outer surface of the outer flange 42 and a mounting groove 15c formed on the outer casing 15. The leaf spring 28 presses the outlet guide vane 40 against the engagement groove 15b of the outer casing 15. Thus, the outlet guide vane 40 becomes stable.
Next, the support structure in the inner diffuser 21 is described as follows. As shown in
The outer peripheral surface of the inner flange 44 is located in substantially the same radial position as the outer peripheral surface of the inner diffuser 21, which is adjacent to the smaller-diameter part 50, or located radially outward relatively. As described above, the engagement part 48 is inserted into and engaged in the engagement groove 56. In this way, the second smaller-diameter part 54 and the engagement groove 56 are formed by utilizing available space of an inlet of the inner diffuser 21, which is downstream of the outlet guide vane 40. Because the inner diffuser 21 is divided two parts in the circumferential direction, the guide vane piece 45 can be assembled to the inner diffuser 21 through the cross-section of the divided parts.
Between an axial rear edge (rear end surface) 48ba of the engagement part 48b of the outlet guide vane 40 and an axially inside surface 56a (axially inside surface) of the engagement groove 56 of the inner diffuser 21, a gap S1 is formed. Therefore, axial thermal expansion of the outlet guide vane 40 and axial thermal expansion of the inner diffuser 21 can be absorbed. There is a slight gap between the engagement part 48b and the engagement groove 56 during a stopped state. As a result, radial thermal expansion of the outlet guide vane 40 can be permitted.
Moreover, a downstream surface 47 of the inner flange 44 and a recessed rear surface 21a of the inner diffuser 21 are close to each other. The outer surface 48bb of the engagement part 48b of the inner flange 44 and the outer surface 56b of the engagement groove 56 of the inner diffuser 21 are also close to each other. The rear edge 48ba of the inner flange 44 and the inside surface 56a of the inner diffuser 21 are close. The inner surface 48bc of the inner flange 44 and the outer peripheral surface (bottom surface) 54a of the first smaller-diameter part 52 of the inner diffuser 21 are close to each other. Thus, since a narrow structure is formed as above mentioned, air leakage can be prevented.
<Support Structure of Stator Vane Piece>
A support structure of the stator vane piece 35 is shown in
At first, here is the support structure in the outer casing 15. The support structure in the outer casing 15 is fundamentally the same as that of the guide vane piece 45. Specifically, the outer casing 15 is provided with a pair of front and rear engagement grooves 15a. The engagement parts 33 of the outer flange 32 are inserted into the engagement grooves 15a, respectively. A leaf spring 28 is inserted between the outer surface of the outer flange 32 and a mounting groove 15a formed on the outer casing 15. Between each engagement part 33 and the corresponding engagement groove 15a, a proper gap (clearance) is provided in both of the axial and the radial directions.
Second, the support structure in the inner diffuser 21 is described below. As mentioned above, the inner diffuser 21 has the smaller-diameter part 50. The stator vane piece 35 is on the outer peripheral surface of the smaller-diameter part 50. The foreside of the smaller-diameter part 50 (foreside of the inner diffuser 21) has a protruding part (engaged part) 58 extending forward. The protruding part 58 is between the inner flange 34 and the engagement part 36b. The outer peripheral surface of the inner flange 44 of the outlet guide vane 40 and the outer peripheral surface of the inner flange 34 of the stator vane 30 are coplanar with each other.
During the operation of the gas turbine, the engagement part 36b is thermally expanded and the outer surface 36bb contacts the inner peripheral surface 58b of the protruding part 58 of the inner diffuser 21. A front edge surface 58a of the protruding part 58 of the inner diffuser 21 is a cylindrical surface concentric with the center axis C of the compressor 3, and therefore the protruding part 58 can be machined easily.
Between the axial rear edge surface (rear edge surface) 36ba of the engagement part 36b and the front end surface 21b, a gap S2 is formed. Between the rear edge surface 58a of the protruding part 58 and the rear edge surface 36aa of the projecting part 36a, a gap S3 is formed. In addition, during the shutdown, a slight gap is formed between the outer surface 36bb of the engagement part 36b and the inner peripheral surface 58b of the protruding part 58. This makes it possible to permit the thermal expansion of the stator vane 30.
The inclined surface 37 which is the foreside surface of the engagement part 36 is inclined radially inward in a rearward direction. The inclined surface 37 and the compressor rotor 11A constitute an inlet 60a of an oblique passage 60 extending to the inside of the inner diffuser 21. Air which has gone into inside of the diffuser 21 through the passage 60 can seal lubricating oil fed to the bearing 24B (see
Although description has been given of the preferred embodiment of the present invention with reference to the drawings, the present invention can be added, changed or deleted in various ways within a scope of the present invention. For example, to more effectively suppress air leakage between the outlet guide vane 40 and the inner diffuser 21 of
3 compressor
15 outer casing
21 inner diffuser
40 outlet guide vane
44 inner flange
48 engagement part
48
a projecting part
48
b engagement part
50 smaller-diameter part
56 engagement groove
Number | Date | Country | Kind |
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2010-064202 | Mar 2010 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2011/001610 | 3/18/2011 | WO | 00 | 10/16/2012 |