Patent Application
20130011238
The present invention relates to ring segments for gas turbine engines and, more particularly, to cooling of ring segments in gas turbine engines.
It is known that the maximum power output of a combustion turbine is achieved by heating the gas flowing through the combustion section to as high a temperature as is feasible. The hot gas, however, heats the various turbine components, such as the combustor and transition ducts, and vanes and ring segments, which it passes when flowing through the turbine section. One aspect limiting the ability to increase the combustion firing temperature is the ability of the turbine components to withstand increased temperatures. Consequently, various cooling methods have been developed to cool turbine hot parts.
In the case of ring segments, ring segments typically may include an impingement tube, also known as an impingement plate, associated with the ring segment and defining a plenum between the impingement tube and the ring segment. The impingement tube may include holes for passage of cooling fluid into the plenum, wherein cooling fluid passing through the holes in the impingement tube may impinge on the outer side of the ring segment to provide impingement cooling to the ring segment. In addition, further cooling structure, such as internal cooling passages, may be formed in the ring segment to facilitate cooling thereof.
In accordance with an aspect of the invention, a ring segment is provided for a gas turbine engine. The ring segment comprises a panel and a first mating edge cooling system. The panel includes a leading edge, a trailing edge, a first mating edge, a second mating edge, an outer side, and an inner side. Cooling fluid is provided to the outer side of the panel and the inner side of the panel defines at least a portion of a hot gas flow path through the gas turbine engine. The first mating edge cooling system is within the panel and receives a portion of the cooling fluid provided to the outer side of the panel for cooling the panel at one of the first and second mating edges. The first mating edge cooling system comprises at least one first mating edge impingement chamber. Each first mating edge impingement chamber includes at least one metering supply passage and at least one metering discharge passage. The at least one metering supply passage extends from the outer side of the panel to the first mating edge impingement chamber. Cooling fluid impinges on a surface of the panel defining the first mating edge impingement chamber as it flows into the first mating edge impingement chamber through the at least one metering supply passage. The at least one metering discharge passage extends from the first mating edge impingement chamber to the one of the first and second mating edges of the panel.
In accordance with another aspect of the invention, a ring segment is provided for a gas turbine engine. The ring segment comprises a panel, a central recessed portion, recess portion walls, and at least one impingement chamber. The panel includes side edges comprising a leading edge, a trailing edge, a first mating edge, and a second mating edge. The panel further includes an outer side and an inner side, wherein cooling fluid is provided to the outer side and the inner side defines at least a portion of a hot gas flow path through the gas turbine engine. The central recessed portion defines a recessed surface formed in the outer side of the panel and is surrounded by a rim portion comprising an unrecessed portion extending around an outer periphery of the recessed portion along each of the side edges. The recess portion walls define the outer periphery of the recessed portion. Each recess portion wall extends radially between the recessed surface and the unrecessed portion. The at least one impingement chamber is located in the panel and includes at least one metering supply passage extending from the outer side for passage of cooling fluid into the impingement chamber to impinge on and cool a surface of the impingement chamber and at least one metering discharge passage extending from the impingement chamber to one of the side edges for passage of cooling fluid from the impingement chamber to the one side edge.
While the specification concludes with claims particularly pointing out and distinctly claiming the present invention, it is believed that the present invention will be better understood from the following description in conjunction with the accompanying Drawing Figures, in which like reference numerals identify like elements, and wherein:
In the following detailed description of the preferred embodiment, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration, and not by way of limitation, a specific preferred embodiment in which the invention may be practiced. It is to be understood that other embodiments may be utilized and that changes may be made without departing from the spirit and scope of the present invention.
In accordance with an aspect of the invention, an outer seal structure 22 is provided about and adjacent the row 12a of blades. The seal structure 22 comprises a plurality of ring segments 24, which, when positioned side by side in a circumferential direction, define the seal structure 22. The seal structure 22 has a ring shape so as to extend circumferentially about its corresponding row 12a of blades. A corresponding one of the seal structures 22 may be provided about each row of blades provided in the turbine section 10.
The seal structure 22 comprises an inner wall of a turbine housing in which the rotating blade rows are provided and defines sealing structure for preventing or limiting the working gas from passing through the inner wall and reaching other structure of the turbine housing, such as a blade ring carrier 26 and an associated annular cooling fluid plenum 28. It is noted that the terms “inner”, “outer”, “radial”, “axial”, “circumferential”, and the like, as used herein, are not intended to be limiting with regard to orientation of the elements recited for the present invention.
Referring to
Referring to
Referring to
Each ring segment 24 of the seal structure 22 comprises a plurality of cooling systems, each of which will be discussed below. However, the cooling systems of only a single one of the ring segments 24 will be described herein, it being understood that the cooling systems of the remaining ring segments 24 are substantially the same as the cooling systems of the ring segment 24 described.
Referring to
The trailing edge cooling system 70 comprises a plurality of metering supply passages 80 formed in the central recessed portion 60 of the panel 30. The metering supply passages 80 of the trailing edge cooling system 70 in the embodiment shown are located toward the leading edge 32 of the panel 30 but could be located elsewhere. The metering supply passages 80 direct a portion of the cooling fluid provided from the cooling fluid plenum 28 to the outer side 40 of the panel 30 into impingement chambers 82 of the trailing edge cooling system 70. As the cooling fluid enters the trailing edge impingement chambers 82 through the metering supply passages 80 it impinges on a surface of the panel 30 that defines the corresponding impingement chamber 82. Sizing of diameters of the trailing edge metering supply passages 80 will be discussed below. While six circumferentially spaced apart trailing edge impingement chambers 82 are illustrated in
As shown in
The trailing edge impingement chambers 82 are each associated with a corresponding discharge passage 84 of the trailing edge cooling system 70. The trailing edge discharge passages 84 extend from the respective trailing edge impingement chambers 82 to the trailing edge 34 of the panel 30 for discharging cooling fluid from the trailing edge impingement chambers 82.
As shown in
As the cooling fluid enters the first and second mating edge impingement chambers 94, 96 through the respective metering supply passages 90, 92 it impinges on surfaces of the panel 30 that define the respective first and second mating edge impingement chambers 94, 96. Due to the location and spacing of the metering supply passages 90, 92, impingement cooling is provided across a substantial area of the panel 30 near the respective first and second mating edges 36, 38 of the panel 30. While the first and second mating edge impingement chambers 94, 96 are illustrated in
As shown in
It is noted that the trailing edge impingement chambers 82 and the first and second mating edge impingement chambers 94, 96 are not in fluid communication with one another, as illustrated in
The first and second mating edge impingement chambers 94, 96 are each associated with a plurality of corresponding metering discharge passages 98, 100. The metering discharge passages 98, 100 extend from the respective first and second mating edge impingement chambers 94, 96 to the corresponding mating edges 36, 38 of the panel 30 for discharging cooling fluid from the first and second mating edge impingement chambers 94, 96. As illustrated in
The panel 30 may include circumferential seal slots (not shown) along the leading and trailing edges 32, 34 for engaging circumferential seals (not shown) extending between the leading and trailing edges 32, 34 and respective edges of adjacent vane platforms 110, 112, see
During operation of the engine, cooling fluid may be supplied to the cooling fluid plenum 28 via the channel 56 formed in the blade ring carrier 26. The cooling fluid in the cooling fluid plenum 28 flows through the impingement holes 58 in the impingement tube 50 where the cooling fluid impinges on the outer side 40 of the panel 30 to provide impingement cooling to the outer side 40 of the panel 30. Portions of this cooling fluid pass into the metering supply passages 80, 90, 92 of the trailing edge cooling system 70 and the first and second mating edge cooling system 72, 74.
The portion of the cooling fluid passing into the metering supply passages 80 of the trailing edge cooling system 70 impinges on the respective portions of the panel 30 that define the trailing edge impingement chambers 82. Thereafter, this portion of the cooling fluid provides convective cooling to the panel 30 as it flows axially downstream through the trailing edge impingement chambers 82. The cooling fluid then exits the panel 30 through the trailing edge discharge passages 84. Upon exiting the trailing edge discharge passages 84, this portion of the cooling fluid may provide impingement cooling for the adjacent downstream vane platform 112 and then may be mixed with the hot working gas flowing through the hot gas flow path 20.
The portions of the cooling fluid passing into the metering supply passages 90, 92 of the first and second mating edge cooling system 72, 74 impinge on the respective portions of the panel 30 that define the first and second mating edge impingement chambers 94, 96. Thereafter, these portions of the cooling fluid exit the panel 30 through the respective first and second mating edge discharge passages 98, 100. These portions of the cooling fluid flow provide convective cooling to the panel 30 as they flow within the first and second mating edge impingement chambers 94, 96 and the first and second mating edge discharge passages 98, 100. Upon exiting the first and second mating edge discharge passages 98, 100, these portions of the cooling fluid may provide impingement cooling for the respective adjacent ring segments and then may provide a cooling air barrier to discourage hot working gases from flowing radially outwardly before being mixed with the hot working gas flowing through the hot gas flow path 20.
It is believed that the present configuration for the ring segment 24 provides an efficient cooling of the panel 30 via the impingement and convective cooling provided by the cooling fluid, and that the efficient cooling of the ring segment 24 may result in a lower cooling fluid requirement than prior art ring segments. Hence, enhanced cooling may be provided within the ring segment 24 while minimizing the volume of cooling fluid discharged from the ring segment 24 into the hot working gas, with an associated improvement in engine efficiency. Further, the distributed cooling provided to the panel 30 may improve the uniformity of temperature distribution across the ring segment 24, with an associated reduction in the metal temperature and reduction in thermal stress, resulting in an improved or extended life of the ring segment 24.
Further, the diameters of the metering supply passages 80, 90, 92 of the trailing edge cooling system 70 and the first and second mating edge cooling systems 72, 74 may be configured as to allow desired amounts of cooling fluid into the respective cooling systems 70, 72, 74. For example, it may be desirable to size the first and second mating edge metering supply passages 90, 92 relative to the trailing edge metering supply passages 80 such that adequate cooling fluid is provided into each of the cooling systems 70, 72, 74. Variables that may be considered are, for example, a pressure gradient that exists between the trailing edge 34 and the first and second mating edges 36, 38, and/or the number of metering supply passages 80, 90, 92 that are provided for the associated cooling system 70, 72, 74. For example, since the pressure at the trailing edge 34 is lower than pressures at the first and second mating edges 36, 38 during operation, larger first and second mating edge metering supply passages 90, 92 may be desirable. However, if the number of first and second mating edge metering supply passages 90, 92 is greater than the number of trailing edge metering supply passages 80, larger trailing edge metering supply passages 80 may be desirable. Moreover, it may be desirable that ones of the first and second mating edge metering supply passages 90, 92 closer to the leading edge 32 of the panel 30 be larger than ones of the first and second mating edge metering supply passages 90, 92 closer to the trailing edge 34. This could be due to a pressure gradient that exists between the leading edge 32 and the trailing edge 34 and/or a larger need for cooling fluid near the leading edge 32, i.e., due to higher working gas temperatures at the leading edge 32.
Moreover, as the cooling fluid associated with the first and second mating edge cooling systems 72, 74 is metered twice, i.e., a first time at the metering supply passages 90, 92 and a second time at the metering discharge passages 98, 100, amounts of cooling fluid provided to the first and second mating edge cooling systems 72, 74 are believed to be more accurately controlled.
Referring now to
The ring segment 224 includes a panel 230 having side edges including a leading edge 232, a trailing edge 234, a first mating edge 236, and a second mating edge 238. The panel 230 further includes an outer side 240 and an inner side (not shown in this embodiment), wherein the inner side defines a corresponding portion of a hot gas flow path as discussed above. The panel 230 defines a structural body for the ring segment 224, and includes a plurality of front flanges or hook members 244a and a plurality of rear flanges or hook members 244b for mounting the ring segment 224 to a blade ring carrier (not shown in this embodiment) as discussed above.
In this embodiment, the ring segment 224 includes a trailing edge cooling system 270, a first mating edge cooling system 272, a second mating edge cooling system 274, and a leading edge cooling system 400 formed within the panel 230.
The trailing edge cooling system 270 comprises a plurality of metering supply passages 280 formed in a central recessed portion 260 of the panel 230. The metering supply passages 280 of the trailing edge cooling system 270 direct a portion of cooling fluid provided from a cooling fluid plenum (not shown in this embodiment) to the outer side 240 of the panel 230 into impingement chambers 282 of the trailing edge cooling system 270. As the cooling fluid enters the trailing edge impingement chambers 282 from the metering supply passages 280 it impinges on a surface of the panel 230 that defines the corresponding impingement chamber 282. As shown in
As shown in
The trailing edge impingement chambers 282 are each associated with a corresponding discharge passage 284 of the trailing edge cooling system 270. The trailing edge discharge passages 284 extend from the respective trailing edge impingement chambers 282 to the trailing edge 234 of the panel 230 for discharging cooling fluid from the trailing edge impingement chambers 282.
The first and second mating edge cooling systems 272, 274 each comprise a plurality of metering supply passages 290, 292 formed in the central recessed portion 260 of the panel 230 in this embodiment. The metering supply passages 290 of the first mating edge cooling system 272 in the embodiment shown are located toward the first mating edge 236 of the panel 230 and direct a portion of the cooling fluid provided from the cooling fluid plenum to the outer side 240 of the panel 230 into a plurality of impingement chambers 294 of the first mating edge cooling system 272. The metering supply passages 292 of the second mating edge cooling system 274 in the embodiment shown are located toward the second mating edge 238 of the panel 230 and direct a portion of the cooling fluid provided from the cooling fluid plenum to the outer side 240 of the panel 230 into a plurality of impingement chambers 296 of the second mating edge cooling system 274.
As the cooling fluid enters the first and second mating edge impingement chambers 294, 296 through the metering supply passages 290, 292 it impinges on respective surfaces of the panel 230 that define the corresponding first and second mating edge impingement chambers 294, 296. The metering supply passages 290, 292 provide impingement cooling fluid across areas of the panel 230 near the respective first and second mating edges 236, 238 of the panel 230. While the first and second mating edge impingement chambers 294, 296 are illustrated in
The first and second mating edge impingement chambers 294, 296 are each associated with a plurality of corresponding metering discharge passages 298, 300. The metering discharge passages 298, 300 extend from the first and second mating edge impingement chambers 294, 296 to the respective mating edges 236, 238 of the panel 230 for discharging cooling fluid from the first and second mating edge impingement chambers 294, 296. As illustrated in
The leading edge cooling system 400 comprises a plurality of metering supply passages 402 formed in the central recessed portion 260 of the panel 230. The metering supply passages 402 of the leading edge cooling system 400 in the embodiment shown are located toward the leading edge 232 of the panel 230 and direct a portion of the cooling fluid provided from the cooling fluid plenum to the outer side 240 of the panel 230 into a plurality of impingement chambers 404 of the leading edge cooling system 400. As the cooling fluid enters the leading edge impingement chambers 404 through the respective metering supply passages 402 it impinges on respective surfaces of the panel 230 that define the corresponding leading edge impingement chambers 404 such that the metering supply passages 402 provide impingement cooling fluid across an area of the panel 230 near the leading edge 232 of the panel 230. While the leading edge impingement chambers 404 are illustrated in
The leading edge impingement chambers 404 are each associated with a plurality of corresponding metering discharge passages 406. The metering discharge passages 406 extend from the leading edge impingement chambers 404 to the leading edge 232 of the panel 230 for discharging cooling fluid from the leading edge impingement chambers 404.
It is noted that the trailing edge impingement chambers 282, the first and second mating edge impingement chambers 294, 296, and the leading edge impingement chambers 404 are not in fluid communication with one another, as illustrated in
It is further noted that the trailing edge impingement chambers 282 (and the trailing edge discharge passages 284) and the leading edge discharge passages 406 can be EDM drilled into the panel 230 to facilitate an advantageous manufacture of the ring segment 224.
While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.
