Vane, gas turbine provided with the same, method of manufacturing vane, and method of remodeling vane

A retainer that protrudes from an inner shroud of a vane to a radially inner side and extends in a circumferential direction is formed with an opening that passes through the retainer in an axial direction and defines a space through which air flows. A width of the opening in the circumferential direction is wider than a width of a vane body in the circumferential direction at a radially inner end of the vane body at a position of the retainer in the axial direction.

TECHNICAL FIELD

The present invention relates to a vane, a gas turbine provided with the same, a method of manufacturing a vane, and a method of remodeling a vane.

Priority is claimed on Japanese Patent Application No. 2014-134418, filed on Jun. 30, 2014, the content of which is incorporated herein by reference.

BACKGROUND ART

A gas turbine is provided with a compressor that compresses atmospheric air to produce compressed air, combustors that burn fuel in the compressed air to produce a combustion gas, and a turbine that is driven by the combustion gas. The turbine has a turbine rotor rotating about an axis, a plurality of vane stages that are arranged in an axial direction in which the axis extends, and a turbine casing that rotatably covers the turbine rotor. The turbine rotor has a rotor shaft that is centered on the axis and extends in the axial direction, and a plurality of blade stages that are fixed to the rotor shaft. Each of the plurality of blade stages has a plurality of blades arranged around the axis in a circumferential direction. One of the plurality of vane stages is disposed upstream from each of the plurality of blade stages. Each of the plurality of vane stages has a plurality of vanes arranged around the axis in the circumferential direction.

Such a vane is described in, for instance, Patent Literature 1 below. This vane is provided with a vane body that extends in a radial direction with respect to the axis, an outer shroud that is formed at a radially outer side of the vane body, an inner shroud that is formed at a radially inner side of the vane body, and a support rail (or a retainer) that protrudes from the inner shroud to the radially inner side and extends in the circumferential direction.

The support rail is formed with a through-hole passing through it in the axial direction. This through-hole is formed to guide air downstream from an upstream side in the axial direction with respect to the support rail.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

A radially outer surface of the inner shroud, i.e., a surface facing the outer shroud, is a surface coming into contact with a combustion gas. For this reason, to protect the inner shroud from the combustion gas of a high temperature, it is necessary to cool this inner shroud with a cooling medium such as air. For this purpose, the inner shroud described in Patent Literature 1 is formed with a cooling air flow path through which the air flows, and the through-hole is formed in the support rail.

In the vane described in Patent Literature 1, a portion of the inner shroud at which the retainer is provided has higher rigidity than other portions. For this reason, in the vane described in Patent Literature 1, high thermal stress occurs at the portion of the inner shroud at which the retainer is provided. Therefore, in the vane described in Patent Literature 1, it is difficult to increase the durability.

Thus, the present invention is intended to provide a technology capable of suppressing thermal stress to increase durability.

Solution to Problem

To accomplish the above object, a vane of an aspect of the present invention is disposed upstream in an axial direction, in which an axis extends, from a blade of a turbine rotor rotating about the axis, and includes: a vane body configured to extend in a radial direction with respect to the axis; an outer shroud formed at a radially outer side of the vane body; an inner shroud formed at a radially inner side of the vane body and configured to form a combustion gas flow path through which a combustion gas flows between the outer shroud and the inner shroud; and a retainer configured to protrude from the inner shroud to the radially inner side and extend in a circumferential direction centering on the axis at a position between an upstream edge of the inner shroud in the axial direction and a downstream edge of the inner shroud in the axial direction, wherein the retainer is formed with an opening that passes through the retainer in the axial direction and defines a space through which air flows, and a width of the opening in the circumferential direction is wider than a width of the vane body in the circumferential direction at a radially inner end of the vane body at a position of the retainer in the axial direction.

In this vane, the area of the opening of the retainer is greater than that of the opening of the support rail (or the retainer) in the vane described in Patent Literature 1. For this reason, the rigidity of the retainer of this vane is lower than that of the support rail (or the retainer) of the vane described in Patent Literature 1. Also, in this vane, the width of the opening of the retainer in the circumferential direction is wider than that of the vane body in the circumferential direction at the radially inner end of the vane body at the position of the retainer in the axial direction. For this reason, a position at which the retainer is provided in the inner shroud and a position at which the vane body is provided in the inner shroud can avoid overlapping each other in the circumferential direction. Therefore, in this vane, the rigidity around the inner shroud is lower than that of the vane described in Patent Literature 1. Accordingly, in this vane, it is possible to suppress thermal stress occurring at the inner shroud.

Here, in the vane, the inner shroud may have an inner shroud main body which extends in the axial and circumferential directions and whose radially outer surface comes into contact with the combustion gas, and a peripheral wall that protrudes from the inner shroud main body to the radially inner side along an outer peripheral edge of the inner shroud main body. The inner shroud may be formed with a recess recessed toward the radially outer side by the inner shroud main body and the peripheral wall. The vane may include an impingement plate which partitions an inside of the recess into a region of the radially inner side and an inner cavity that is a region of the radially outer side and in which a plurality of air holes are formed. A radially inner edge of the opening may be located at the radially inner side relative to a radially inner surface of the impingement plate, and a radially outer edge of the opening may be located at the radially outer side relative to a radially outer surface of the impingement plate.

In this vane, the portion at which the retainer is located in the axial direction within the radially inner surface of the inner shroud main body can be subjected to impingement cooling. For this reason, in this vane, it is possible to effectively cool the portion at which the retainer is located in the axial direction. Particularly, in this vane, as the width of the opening in the circumferential direction is wider than that of the vane body in the circumferential direction at the position of the retainer in the axial direction, the impingement plate can be disposed inside the opening as well. For this reason, in this vane, a range within which the impingement cooling is possible with air flowing through the plurality of air holes of the impingement plate at the position of the retainer in the axial direction can be made wider than in the vane described in Patent Literature 1. Therefore, in this vane, it is possible to further suppress the thermal stress occurring at the inner shroud.

Also, in any of the foregoing vanes, one edge of the opening which is located at one side in the circumferential direction may be located at the one side relative to an outer surface of the vane body which is located at the one side at the radially inner end of the vane body at the position of the retainer in the axial direction; and the other edge of the opening which is located at the other side in the circumferential direction may be located at the other side relative to an outer surface of the vane body which is located at the other side at the radially inner end of the vane body at the position of the retainer in the axial direction.

In this vane, overlap in the circumferential direction between the position at which the retainer is provided in the inner shroud and the position at which the vane body is provided in the inner shroud can be reliably avoided.

In any of the foregoing vanes in which the recess is formed in the inner shroud, of inner circumferential surfaces of the opening that passes through the retainer in the axial direction, the surface facing the radially outer side may be gradually inclined toward the radially outer side from the upstream side to the downstream side.

In this vane, of the inner circumferential surfaces of the opening, the surface facing the radially outer side is gradually inclined toward the radially outer side from the upstream side to the downstream side. For this reason, in this vane, it is possible to slant the impingement plate with respect to the surface of the inner shroud main body at the radially inner side to easily mount or demount the impingement plate.

In any of the foregoing vanes in which the recess is formed in the inner shroud, the impingement plate may be inserted into the opening, and may be formed by a single perforated plate that extends upstream and downstream from the retainer.

In the vane in which the impingement plate is formed by the single perforated plate, the single perforated plate forming the impingement plate may be configured in such a manner that a perforated plate located upstream and a perforated plate located downstream are joined in one body.

In this vane, since the width of the opening in the circumferential direction is enlarged compared to the opening of the retainer described in Patent Literature 1, the plurality of perforated plates can be reliably joined in one body. As a result, leakage of cooling air at a joined portion is reduced, so that a cooling effect based on the impingement cooling is improved, and an amount of cooling air is reduced.

In any of the foregoing vanes in which the recess is formed in the inner shroud, the vane may include a sealing plate that is disposed downstream from the retainer and blocks a portion of an opening of the recess downstream from the retainer.

In any of the foregoing vanes in which the recess is formed in the inner shroud, the peripheral wall of the inner shroud may have a pair of lateral peripheral walls that are opposite to each other at an interval in the circumferential direction. The one edge of the opening which is located at the one side in the circumferential direction may be located within a surface adjacent to the inner cavity of one of the pair of lateral peripheral walls which is located at the one side, and the other edge of the opening which is located at the other side in the circumferential direction may be located within a surface adjacent to the inner cavity of the other of the pair of lateral peripheral walls which is located at the other side.

In this vane, the area of the opening of the retainer becomes greater, and the rigidity of the retainer becomes lower. Moreover, the impingement plate is disposed inside the opening as well. Thereby, the range within which the impingement cooling is possible at the axial position of the retainer on the radially inner region of the inner shroud can be widened in the circumferential direction. For this reason, in this vane, the thermal stress occurring at the inner shroud can be further suppressed. Moreover, in this vane, the portion at which the retainer is located in the axial direction within the radially inner surface of the inner shroud main body can be nearly uniformly cooled almost as a whole in the circumferential direction. Therefore, in this vane, from this viewpoint, too, the thermal stress occurring at the inner shroud can be further suppressed.

In any of the foregoing vanes in which the recess is formed in the inner shroud, the inner shroud main body may be formed with a downstream end face facing downstream, and the inner shroud may be formed with a cooling air ejection hole that passes through the inner shroud from the inner cavity and is open at the downstream end face of the inner shroud main body.

In the vane in which the cooling air ejection hole is formed, the inner shroud may be formed with a plurality of cooling air ejection holes arranged in the circumferential direction.

In any of the foregoing vanes in which the recess is formed in the inner shroud, the inner shroud main body may be formed with a cooling air ejection hole that passes through the inner shroud main body from the inner cavity toward the radially outer side.

To accomplish the above object, a gas turbine of an aspect of the present invention includes a plurality of vanes, each of which is any of the foregoing vanes, the turbine rotor, a turbine casing which rotatably covers the turbine rotor and to an inner circumferential side of which the vanes are fixed, and combustors fixed to the turbine casing to produce the combustion gas.

Since this gas turbine is also provided with the vane described above, the durability of the vane can be increased.

To accomplish the above object, in an aspect of the present invention, there is provided a method of manufacturing a vane which is disposed upstream in an axial direction, in which an axis extends, from a blade of a turbine rotor rotating about the axis, and includes a vane body configured to extend in a radial direction with respect to the axis, an outer shroud formed at a radially outer side of the vane body, an inner shroud formed at a radially inner side of the vane body and configured to form a combustion gas flow path through which a combustion gas flows between the outer shroud and the inner shroud, and a retainer configured to protrude from the inner shroud to the radially inner side and extend in a circumferential direction centering on the axis at a position between an upstream edge of the inner shroud in the axial direction and a downstream edge of the inner shroud in the axial direction, the retainer being formed with an opening that passes through the retainer in the axial direction and defines a space through which air flows, the method including forming the following in one body by casting: the retainer in which the opening is formed such that a width thereof in the circumferential direction is wider than a width of the vane body in the circumferential direction at a radially inner end of the vane body at a position of the retainer in the axial direction, the vane body, the outer shroud, and the inner shroud.

To accomplish the above object, in an aspect of the present invention, there is provided a method of remodeling a vane which is disposed upstream in an axial direction, in which an axis extends, from a blade of a turbine rotor rotating about the axis, and includes a vane body configured to extend in a radial direction with respect to the axis, an outer shroud formed at a radially outer side of the vane body, an inner shroud formed at a radially inner side of the vane body and configured to form a combustion gas flow path through which a combustion gas flows between the outer shroud and the inner shroud, and a retainer configured to protrude from the inner shroud to the radially inner side and extend in a circumferential direction centering on the axis at a position between an upstream edge of the inner shroud in the axial direction and a downstream edge of the inner shroud in the axial direction, the retainer being formed with an opening that passes through the retainer in the axial direction and defines a space through which air flows, the method including processing the retainer such that a width of the opening in the circumferential direction becomes wider than a width of the vane body in the circumferential direction at a radially inner end of the vane body at a position of the retainer in the axial direction.

Here, in the method of remodeling a vane, prior to processing the retainer, the width of the opening in the circumferential direction may be narrower than the width of the vane body in the circumferential direction at the radially inner end of the vane body at the position of the retainer in the axial direction, and during processing of the retainer, the retainer may be ground to enlarge the opening.

Advantageous Effects of Invention

In an aspect of the present invention, it is possible to suppress thermal stress occurring at an inner shroud of a vane. Therefore, according to the aspect of the present invention, it is possible to increase the durability of the vane.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of a vane according to the present invention, an embodiment of a gas turbine provided with the same, and various modifications of the vane will be described in detail with reference to the drawings.

Embodiments

The embodiment of the vane according to the present invention and the embodiment of the gas turbine provided with the same will be described with reference toFIGS. 1 to 12.

As illustrated inFIG. 1, the gas turbine of the present embodiment is provided with a compressor10that compresses air, combustors20that burn fuel in the air compressed by the compressor10to generate a combustion gas, and a turbine30that is driven by the combustion gas.

As illustrated inFIGS. 1 and 2, the compressor10has a compressor rotor11rotating about an axis Ar, a compressor casing15that rotatably covers the compressor rotor11, and a plurality of vane stages14. Hereinafter, a direction in which the axis Ar extends is defined as an axial direction Da, one side of this axial direction Da is defined as an upstream side, and the other side of this axial direction Da is defined as a downstream side. Also, a circumferential direction centering on this axis Ar is simply defined as a circumferential direction Dc, and a direction perpendicular to the axis Ar is defined as a radial direction Dr. The compressor rotor11has a rotor shaft12that is centered on the axis Ar and extends in the axial direction Da, and a plurality of blade stages13that are mounted on the rotor shaft12. The plurality of blade stages13are arranged in the axial direction Da. Each of the plurality of blade stages13is made up of a plurality of blades arranged in the circumferential direction Dc. The vane stages14are disposed respectively upstream from the plurality of blade stages13. The vane stages14are provided inside the compressor casing15. Each of the plurality of vane stages14is made up of a plurality of vanes arranged in the circumferential direction Dc. An annular space within a region which is between a radially outer circumferential side of the rotor shaft12and a radially inner circumferential side of the compressor casing15and within which the vane stages14and the blade stages13are disposed in the axial direction Da forms an air compression flow path19in which air is compressed while flowing.

The turbine30has a turbine rotor31that rotates about the axis Ar, a turbine casing35that rotatably covers the turbine rotor31, and a plurality of vane stages34. The combustors20are fixed to an upstream portion of the turbine casing35. The turbine rotor31has a rotor shaft32that is centered on the axis Ar and extends in the axial direction Da, and a plurality of blade stages33that are mounted on the rotor shaft32. The plurality of blade stages33are arranged in the axial direction Da. Each of the plurality of blade stages33is made up of a plurality of blades arranged in the circumferential direction Dc. The vane stages34are disposed respectively upstream from the plurality of blade stages33. The vane stages34are provided inside the turbine casing35. As illustrated inFIG. 3, each of the vane stages34is made up of a plurality of vanes40arranged in the circumferential direction Dc. An annular space within a region which is between an outer circumferential side of the rotor shaft32and an inner circumferential side of the turbine casing35and within which the vane stages34and the blade stages33are disposed in the axial direction Da forms a combustion gas flow path39through which a combustion gas G flows from the combustors20.

Each of the combustors20has a combustion liner (or a transition piece)21that sends the combustion gas G of high temperature and pressure into the combustion gas flow path39of the turbine30, and a fuel injector22that injects fuel into the combustion liner21along with air. The fuel injector22has a plurality of nozzles23injecting the fuel into the combustion liner21. The fuel is supplied to each of the nozzles23from a fuel supply source via a fuel line.

The compressor rotor11and the turbine rotor31are located on the same axis Ar, and are interconnected to form a gas turbine rotor1. Also, the compressor casing15and the turbine casing35are interconnected to form a gas turbine casing5. The gas turbine is further provided with an inner cover6that covers an outer circumferential side of the gas turbine rotor1at an inner circumferential side of the gas turbine casing5between the air compression flow path19of the compressor10and the combustion gas flow path39of the turbine30in the axial direction Da. The inner cover6extends up to the position of a first vane stage34flocated furthest upstream in the axial direction Da among the vane stages34of the turbine30.

As illustrated inFIG. 4, each of the plurality of vanes40constituting each of the vane stages34of the turbine30has a vane body41extending in the radial direction Dr, an outer shroud51formed at a radially outer side of the vane body41, and an inner shroud61formed at a radially inner side of the vane body41. A space between the inner shroud61and the outer shroud51forms a part of the aforementioned combustion gas flow path39. Each of the plurality of vanes40fconstituting the first vane stage34flocated furthest upstream among the vane stages34further includes a retainer91that protrudes from the inner shroud61to the radially inner side and extends in the circumferential direction.

The vane body41is formed with cooling air main flow channels42which extend in the radial direction Dr and through which cooling air flows, and a plurality of cooling air ejection holes43that pass through the vane body41from the cooling air main flow channels42toward the upstream side and are open at a leading edge of the vane body41. Further, the vane body41may be formed with a plurality of cooling air ejection holes that pass through the vane body41from the cooling air main flow channels42toward the downstream side and are open at a trailing edge of the vane body41.

The outer shroud51has a plate-like outer shroud main body52that extends in the axial direction Da and the circumferential direction Dc, and a peripheral wall55protruding along an outer peripheral edge of the outer shroud main body52from the outer shroud main body52to the radially outer side. The peripheral wall55has upstream and downstream peripheral walls56and57that are opposite to each other in the axial direction Da, and a pair of lateral peripheral walls58that are opposite to each other in the circumferential direction Dc. Both of the upstream peripheral wall56and the downstream peripheral wall57protrude further to the radially outer side with respect to the outer shroud main body52than the pair of lateral peripheral walls58, and form hook parts. The upstream and downstream peripheral walls56and57forming the hook parts play a role in mounting the vanes40on the inner circumferential side of the turbine casing35. A recess54recessed toward the radially inner side is formed in the outer shroud51by the outer shroud main body52and the peripheral wall55. The cooling air main flow channels42of the vane body41are open within the recess54. Therefore, air from the radially outer side of the outer shroud51flows into the cooling air main flow channels42of the vane body41. The air flowing into the cooling air main flow channels42is ejected from a plurality of cooling air ejection ports into the combustion gas flow path39.

The vane40is further provided with an impingement plate59that partitions the recess54of the outer shroud51into a region of the radially inner side and a region of the radially outer side. The impingement plate59is formed with a plurality of air holes passing therethrough in the radial direction Dr.

As illustrated inFIGS. 4 and 5, the inner shroud61has a plate-like inner shroud main body62that extends in the axial direction Da and the circumferential direction Dc, and a peripheral wall71protruding along an outer peripheral edge of the inner shroud main body62from the inner shroud main body62to the radially inner side.

A radially outer surface of the inner shroud main body62forms a gas path face66coming into contact with the combustion gas. The inner shroud main body62is formed with upstream and downstream end faces63and64that are opposite to each other in the axial direction Da, and a pair of lateral end faces65that are opposite to each other in the circumferential direction Dc. As illustrated inFIG. 3, both of the pair of lateral end faces65are gradually inclined from the upstream side to the downstream side to be located at one side in the circumferential direction Dc. For this reason, when viewed from the radially inner side to the radially outer side, the inner shroud main body62is formed in a parallelogram shape. The peripheral wall71has upstream and downstream peripheral walls73and74that are opposite to each other in the axial direction Da, and a pair of lateral peripheral walls75that are opposite to each other in the circumferential direction Dc. The upstream peripheral wall73extends along the upstream end face63in the circumferential direction Dc at a position that is slightly downstream from the upstream end face63of the inner shroud main body62. The downstream peripheral wall74extends along the downstream end face64in the circumferential direction Dc at a position that is slightly upstream from the downstream end face64of the inner shroud main body62. The lateral peripheral walls75are formed along the lateral end faces65of the inner shroud main body62between the upstream peripheral wall73and the downstream peripheral wall74. A recess84recessed toward the radially outer side is formed in the inner shroud61by the inner shroud main body62and the peripheral wall71. The cooling air main flow channels42of the vane body41are open within the recess54of the outer shroud51as described above and are also open within the recess84of the inner shroud61.

As illustrated inFIGS. 3 to 6, the retainer91is formed at a position within a region of the vane body41in the axial direction Da by extending from one of the pair of lateral peripheral walls75of the inner shroud61in the circumferential direction Dc to the other lateral peripheral wall75. The retainer91protrudes to the radially inner side relative to all of the upstream peripheral wall73, the downstream peripheral wall74, and the lateral peripheral walls75that constitute the peripheral wall71. The retainer91serves to come into contact with a radially outer end6a(seeFIG. 6) of the inner cover6at the downstream side to support a radially inner portion of the vane40fon the radially outer end6a(seeFIG. 6) of the inner cover6at the downstream side.

The retainer91is formed with an opening92(hereinafter referred to as a retainer opening92) passing through it in the axial direction Da to define a space through which air flows. As illustrated inFIGS. 5 and 7, when viewed from the axial direction Da, the retainer opening92is formed in a rectangular shape that is long in the circumferential direction Dc. Among inner circumferential surfaces of the retainer opening92, a first inner circumferential surface93facing one side of the circumferential direction Dc is located in a surface adjacent to the recess84of one lateral peripheral wall75yof the pair of lateral peripheral walls75which is located at the other side in the circumferential direction Dc, and a second inner circumferential surface94facing the other side in the circumferential direction Dc is located in a surface adjacent to the recess84of the other lateral peripheral wall75xof the pair of lateral peripheral walls75which is located at the one side in the circumferential direction Dc. In other words, an edge94eof the retainer opening92at the one side in the circumferential direction Dc is located in the surface adjacent to the recess84of one of the pair of lateral peripheral walls75, i.e., the lateral peripheral wall75xlocated at the one side, and an edge93eof the retainer opening92at the other side in the circumferential direction Dc is located in the surface adjacent to the recess84of the other of the pair of lateral peripheral walls75, i.e., the lateral peripheral wall75ylocated at the other side. Also, the edge94eof the retainer opening92at the one side in the circumferential direction Dc is located at the one side relative to an outer surface48at the one side of the vane body41at a radially inner end of the vane body41at a position of the retainer91in the axial direction Da. Further, the edge93eof the retainer opening92at the other side in the circumferential direction Dc is located at the other side relative to an outer surface47at the other side of the vane body41at the radially inner end of the vane body41at the position of the retainer91in the axial direction Da. That is, a width Wo of the retainer opening92in the circumferential direction Dc is equal to a width of the recess84of the inner shroud61in the circumferential direction Dc, and is wider than a width Ww of the vane body41in the circumferential direction Dc at the radially inner end of the vane body41at the position of the retainer91in the axial direction Da.

As illustrated inFIGS. 6 and 7, among the inner circumferential surfaces of the retainer opening92, a third inner circumferential surface95facing the radially inner side is included within a radially inner surface67of the inner shroud main body62, and is located at the same position in the radial direction Dr as this radially inner surface67. In other words, a radially outer edge95eof the retainer opening92is included within the radially inner surface67of the inner shroud main body62, and is located at the same position in the radial direction Dr as the radially inner surface67. Among the inner circumferential surfaces of the retainer opening92, a fourth inner circumferential surface96facing the radially outer side is gradually inclined from the upstream side to the downstream side to face the radially outer side. A downstream edge96dof the fourth inner circumferential surface96is located at a position in the radial direction Dr which is approximately the same as a position of radially inner surfaces of the lateral peripheral walls75. Therefore, an upstream edge96uof the fourth inner circumferential surface96is located at the radially inner side relative to the position of the radially inner surfaces of the lateral peripheral walls75.

The plurality of vanes40fconstituting the first vane stage34fare each provided with an impingement plate101that partitions the inside of the aforementioned recess84into a region85of the radially inner side and an inner cavity86that is a region of the radially outer side, and a sealing plate105that blocks a portion of the opening of the recess84downstream from the retainer91. The outer shroud51, the vane body41, the inner shroud61, and the retainer91are formed in one body, and thereby a vane main body MB (seeFIG. 4) is formed. Therefore, the vane40fof the present embodiment is constituted of the impingement plate101, the sealing plate105, the vane main body MB, and the impingement plate59partitioning the recess54of the outer shroud51.

The impingement plate101is inserted into the retainer opening92near the middle of the recess84in the radial direction Dr. Accordingly, the radially outer edge of the retainer opening92is located at the radially outer side relative to the radially outer surface of the impingement plate101, and the radially inner edge of the retainer opening92is located at the radially inner side relative to the radially inner surface of the impingement plate101. An upstream edge of the impingement plate101abuts the upstream peripheral wall73of the inner shroud61, and a downstream edge of the impingement plate101abuts the downstream peripheral wall74of the inner shroud61. Lateral edges of the impingement plate101which are ends in the circumferential direction Dc abut the lateral peripheral walls75of the inner shroud61. The impingement plate101is formed with a plurality of air holes passing through it from the radially inner side toward the radially outer side.

As illustrated inFIGS. 5 to 8, the sealing plate105is located downstream from the retainer91, at the radially inner side relative to the impingement plate101. An upstream edge of the sealing plate105abuts the fourth inner circumferential surface96of the retainer opening92, and a downstream edge of the sealing plate105abuts the downstream peripheral wall74of the inner shroud61. Lateral edges of the sealing plate105which are ends in the circumferential direction Dc abut the lateral peripheral walls75of the inner shroud61.

The inner shroud61is formed with a plurality of first cooling air ejection holes68(seeFIG. 6) that pass through the inner shroud61from the inner cavity86toward the downstream and are open at the downstream end face64of the inner shroud main body62. The plurality of first cooling air ejection holes68are arranged in the circumferential direction Dc (seeFIG. 3). The inner shroud main body62is also formed with a plurality of second cooling air ejection holes69(seeFIG. 6) that pass through the inner shroud main body62from the inner cavity86toward the radially outer side and are open at the gas path face66of the inner shroud main body62.

An operation of the gas turbine described above and a function of the vane40fwill be described.

The compressor10suctions open air, and compresses it to produce compressed air. A part of the compressed air which the compressor10has produced is ejected into the combustion liner21via the fuel injector22of the combustors20. Fuel from the fuel injector22is injected into the combustion liner21. This fuel is burnt in the compressed air inside the combustion liner21. As a result of the combustion, a combustion gas G is produced. This combustion gas G flows from the combustion liner21into the combustion gas flow path39of the turbine30. As the combustion gas G flows through the combustion gas flow path39, the turbine rotor31is rotated.

The vane40fforming a part of the combustion gas flow path39is exposed to the combustion gas of a high temperature. For this reason, as described above, the vanes40fof the present embodiment are formed with flow channels and holes through which cooling air flows.

A part of the compressed air produced by the compressor10flows from the radially outer side of the vane40finto the recess54of the outer shroud51. A part of the compressed air which flows into the recess54of the outer shroud51flows into an outer cavity between the impingement plate59and the outer shroud main body52via the plurality of air holes of the impingement plate59. In this process, the compressed air collides with the outer shroud main body52to carry out impingement cooling on the outer shroud main body. Further, the remaining part of the compressed air which flows into the recess54of the outer shroud51flows into the cooling air main flow channels42of the vane body41to cool the vane body41in a process in which it is ejected from the plurality of cooling air ejection holes43into the combustion gas flow path39and in a process in which it is ejected from the plurality of cooling air ejection holes43again.

Another part of the compressed air which the compressor10has produced flows from the radially inner side of the vane40finto the recess84of the inner shroud61. To be more accurate, the compressed air flows from a portion of the opening of the recess84of the inner shroud61upstream from the retainer91into the region85of the radially inner side in the recess84. Further, the compressed air also flows from the retainer opening92into the region85of the radially inner side in the recess84.

Most of the compressed air which has flowed from the portion of the opening of the recess84of the inner shroud61upstream from the retainer91into the region85of the radially inner side in the recess84flows into the inner cavity86via some of the plurality of air holes102of the impingement plate101upstream from the retainer91. Most of the compressed air flowing into the inner cavity86collides with a portion of the inner shroud main body62upstream from the retainer91to carry out impingement cooling on this portion. Also, most of the compressed air which has flowed from the retainer opening92into the region85of the radially inner side in the recess84flows into the inner cavity86via some of the plurality of air holes102of the impingement plate101downstream from the retainer91. Most of the compressed air flowing into the inner cavity86collides with a portion of the inner shroud main body62downstream from the retainer91to carry out impingement cooling on this portion.

A part of the compressed air flowing into the inner cavity86flows through the plurality of first cooling air ejection holes68, and is ejected from the downstream end face64of the inner shroud main body62into the combustion gas outside the inner shroud61. This compressed air cools a downstream portion of the inner shroud main body62in a process in which it flows through the plurality of first cooling air ejection holes68.

Another part of the compressed air flowing into the inner cavity86flows through the plurality of second cooling air ejection holes69, and is ejected from the gas path face66of the inner shroud main body62to the combustion gas flow path39. This compressed air cools the inner shroud main body62in a process in which it flows through the plurality of second cooling air ejection holes69. Further, this compressed air is ejected to the inner shroud main body62along the gas path face66, thereby carrying out film cooling on this gas path face66.

Here, a vane40cof a comparative example will be described with reference toFIGS. 9 and 10.

A retainer91cof the vane40cof the comparative example is fundamentally different from the retainer91of the vane40fof the present embodiment. The retainer91cof the vane40cof the comparative example is formed to protrude from a radially inner surface of an inner shroud main body62ctoward the radially inner side. A retainer opening92cformed in this retainer91cis formed at a position between an impingement plate101cband the sealing plate105in the radial direction Dr. As illustrated inFIG. 10, when viewed from the axial direction Da, the retainer opening92cis formed in a rectangular shape. A length of the retainer opening92cin the radial direction Dr is smaller than an interval length between the impingement plate101cband the sealing plate105in the radial direction Dr. For this reason, a width of the retainer opening92cin the radial direction Dr is much narrower than that of the retainer opening92of the present embodiment in the radial direction Dr. Also, an inner length Woc, i.e., a width, of the retainer opening92cin the circumferential direction Dc is smaller than the width Ww of the vane body41in the circumferential direction Dc at the radially inner end of the vane body41at a position of the retainer91cin the axial direction Da. That is, an area of the retainer opening92cof the comparative example is much smaller than that of the retainer opening92of the present embodiment.

In this way, since the area of the retainer opening92cof the comparative example is much smaller than that of the retainer opening92of the present embodiment, the rigidity of the retainer91cof the comparative example is higher than that of the retainer91of the present embodiment. Furthermore, in the comparative example, a position at which the retainer91cis provided in the inner shroud main body62cand a position at which the vane body41is provided in the inner shroud main body62coverlap each other in the circumferential direction Dc. In the vane40cof the comparative example, therefore, the rigidity around the inner shroud main body62c, particularly, the rigidity around the position at which the retainer91cis provided in the inner shroud main body62c, is increased. For this reason, in the comparative example, if temperature distribution occurs in the inner shroud main body62c, high thermal stress occurs around the position at which the retainer91cis provided in an inner shroud61c.

On the other hand, since the area of the retainer opening92of the present embodiment is by contrast much greater than that of the retainer opening92cof the comparative example, the rigidity of the retainer91of the present embodiment is lower than that of the retainer91cof the comparative example. Furthermore, in the present embodiment, a position at which the retainer91is provided in the inner shroud61and a position at which the vane body41is provided in the inner shroud61are different from each other in the circumferential direction Dc. Therefore, in the vane40fof the present embodiment, the rigidity around the inner shroud main body62is lower than that of the comparative example. For this reason, in the present embodiment, even if temperature distribution occurs in the inner shroud main body62, the thermal stress occurring at the inner shroud main body62can be suppressed.

As illustrated inFIGS. 9 and 10, the retainer91cillustrated in the comparative example is directed from the inner shroud main body62ctoward the radially inner side and is provided over the full width of the inner shroud main body62cin the circumferential direction Dc. For this reason, the radially inner surface67of the inner shroud main body62cat the position of the retainer91cin the axial direction Da is a region on which the impingement cooling is impossible over the full width of the radially inner surface67in the circumferential direction Dc. On the other hand, the retainer opening92formed in the retainer91of the present embodiment is formed in the circumferential direction Dc to be wider than the width Ww of the vane body41in the circumferential direction Dc at the radially inner end of the vane body41at the position of the retainer91in the axial direction Da, and is formed from the position flush with the radially inner surface67of the inner shroud main body62in the radial direction Dr to the position of the radially inner surfaces of the lateral peripheral walls75(downstream edge96d). For this reason, in the present embodiment, the impingement plate101can be disposed almost throughout an area in the circumferential direction Dc at the portion at which the retainer91is located in the axial direction Da in the radially inner surface67of the inner shroud main body62. Therefore, the impingement cooling can be performed on the radially inner surface67of the inner shroud main body62over the full width in the circumferential direction Dc, including the portion at which the retainer91is located in the axial direction Da. Accordingly, the inner shroud main body62of the present embodiment is almost entirely cooled by compressed air more uniformly than that of the comparative example, including the portion at which the retainer91is located in the axial direction Da. As a result, a temperature difference in the inner shroud main body62of the present embodiment can be made smaller than that of the comparative example. Thus, in the present embodiment, from this viewpoint, too, the thermal stress occurring at the inner shroud main body62can be suppressed.

As described above, in the present embodiment, in comparison with the comparative example, the rigidity around the inner shroud main body62is low, and the temperature difference in the inner shroud main body62is small. Thus, in comparison with the comparative example, the thermal stress occurring at the inner shroud main body62can be reduced. Therefore, in the present embodiment, the durability of the vane40fcan be increased, compared to the comparative example.

Also, in the comparative example, the inside of the recess84cof the inner shroud61cis partitioned into the upstream side and the downstream side by the retainer91c. Thus, as the impingement plates101caand101cbthat partition the recess84cinto the region85of the radially inner side and the inner cavity86of the radially outer side, the upstream impingement plate101cathat partitions the portion in the recess84cupstream from the retainer91cinto the region85of the radially inner side and the inner cavity86of the radially outer side, and the downstream impingement plate101cbthat partitions the portion in the recess84cdownstream from the retainer91cinto the region85of the radially inner side and the inner cavity86of the radially outer side are required.

On the other hand, in the present embodiment, the width Wo of the retainer opening92in the circumferential direction Dc is matched with the width of the recess84of the inner shroud61in the circumferential direction Dc. Thus, even if the impingement plate101is formed of a single perforated plate, this single perforated plate is inserted into the retainer opening92, and thereby the recess84can be partitioned into the region85of the radially inner side and the inner cavity86of the radially outer side.

Next, a method of manufacturing the vane40fof the present embodiment will be described according to a flowchart illustrated inFIG. 11.

In the present embodiment, a process (S10) of manufacturing the vane main body MB, a process (S20) of manufacturing the impingement plates59and101, and a process (S30) of manufacturing the sealing plate105are individually performed.

In the process (S10) of manufacturing the vane main body MB, first, a mold and a core for casting the vane main body MB are manufactured (S11). The core is intended to form the cooling air main flow channels42, etc. in the vane body41. Next, a molten metal is poured into the mold in which the core is incorporated, and an intermediate product of the vane main body MB is cast (S12). In this intermediate product, the outer shroud51, the vane body41, the inner shroud61, and the retainer91are formed in one body. Also, the retainer91is formed with the retainer opening92described above. Next, a finishing process is performed on the intermediate product to complete the vane main body MB (S13). The finishing process includes polishing a surface of the intermediate product, performing thermal barrier coating on the surface of the intermediate product, machining various cooling air ejection holes43,68and69, and so on.

In the process (S20) of manufacturing the impingement plates59and101, first, plates corresponding to the shapes and sizes of the impingement plates59and101are manufactured. Next, a plurality of through-holes are formed in these plates. Finally, a finishing process is performed on the plates in which the plurality of through-holes are formed, i.e., perforated plates, and the impingement plates59and101are finished.

In the process (S30) of manufacturing the sealing plate105, first, a plate corresponding to the shape and size of the sealing plate105is manufactured. Next, a finishing process is performed on this plate, and the sealing plate105is finished.

Once the vane main body MB, the impingement plates59and101, and the sealing plate105are finished, these are assembled (S40). The vane40fof the present embodiment is thus completed.

Next, a method of remodeling into the vane40fof the present embodiment will be described according to a flowchart illustrated inFIG. 12.

Here, as an example, an example in which the vane40cof the comparative example illustrated inFIGS. 9 and 10is remodeled into the vane40fof the present embodiment will be described.

In remodeling the vane40cof the comparative example, the retainer91cof the comparative example is processed to enlarge the retainer opening92cby a processing method such as grinding, and the shape and size of the retainer opening92care fitted to those of the retainer opening92of the present embodiment described above (S10a).

Further, along with the enlargement of the retainer opening92c, the impingement plate and the sealing plate are separately manufactured (S20aand S30a).

Once remodeling of the vane main body is finished and a new impingement plate and sealing plate are manufactured, these are assembled (S40a). The remodeling of the vane40cis thus completed.

A first modification of the vane40fof the above embodiment will be described with reference toFIG. 13.

The size of the retainer opening92of the above embodiment is changed in a vane40aof the present modification, and the other constitutions are the same as those of the vane40fof the above embodiment.

In the vane40aof the present modification, a width Woa of a retainer opening92ain the circumferential direction Dc is narrower than a width of a recess84aof an inner shroud61ain the circumferential direction Dc, but is wider than the width Ww of the vane body41in the circumferential direction Dc at the radially inner end of the vane body41at a position of a retainer91ain the axial direction Da like the above embodiment. Also, the edge94eof the retainer opening92aat the one side in the circumferential direction Dc is located at the one side from the outer surface48at the one side of the vane body41at the radially inner end of the vane body41at the position of the retainer91ain the axial direction Da. Further, the edge93eof the retainer opening92aat the other side in the circumferential direction Dc is located at the other side from the outer surface47at the other side of the vane body41at the radially inner end of the vane body41at the position of the retainer91ain the axial direction Da. Also, a width of the retainer opening92ain the radial direction Dr is the same as in the above embodiment.

Like the above embodiment, an area of the retainer opening92aof the present modification is much greater than an area of the retainer opening92cof the comparative example. Thus, the rigidity of the retainer91aof the present modification is lower than that of the retainer91cof the comparative example. Moreover, in the present modification, a position at which the retainer91ais provided in the inner shroud61aand a position at which the vane body41is provided in the inner shroud61aare different from each other in the circumferential direction Dc. For this reason, in the vane40aof the present modification, too, the rigidity around the inner shroud main body62ais lower than that of the comparative example. Therefore, in the present modification, even if temperature distribution occurs in the inner shroud main body62a, thermal stress occurring at the inner shroud main body62acan be suppressed.

Also, in the present modification, too, the retainer opening92ais formed in the circumferential direction Dc to be wider than the width Ww of the vane body41in the circumferential direction Dc at the radially inner end of the vane body41at the position of the retainer91ain the axial direction Da, and is formed from the position flush with the radially inner surface67of the inner shroud main body62ain the radial direction Dr to the position of the radially inner surfaces of the lateral peripheral walls75(downstream edge96d). For this reason, in the present modification, too, an impingement plate101acan be disposed over a wide region in the circumferential direction Dc at a portion at which the retainer91ais located in the axial direction Da in the radially inner surface67of the inner shroud main body62a. Therefore, impingement cooling can be performed on the radially inner surface67of the inner shroud main body62aover a wide region, including the portion at which the retainer91ais located in the axial direction Da. Accordingly, the portion at which the retainer91ais located in the axial direction Da within the inner shroud main body62aof the present modification can be cooled more than that of the comparative example. Thus, in the present modification, from this viewpoint, too, the thermal stress occurring at the inner shroud main body62acan be suppressed.

As described above, in the present modification, too, the thermal stress occurring at the inner shroud main body62acan be suppressed more than that of the comparative example. Thus, the durability of the vane40acan be increased more than that of the comparative example.

A second modification of the vane40fof the above embodiment will be described with reference toFIG. 14.

The impingement plate101of the above embodiment is changed in a vane40bof the present modification, and the other constitutions are the same as those of the vane40fof the above embodiment.

In the impingement plate101of the above embodiment, the single perforated plate is used as the single impingement plate101with no change. On the other hand, in the present modification, two perforated plates103aand103bare joined in one body, and the joined plates are used as one impingement plate101a. Of the two perforated plates103aand103b, one perforated plate103ais an upstream perforated plate that partitions a portion located upstream from the retainer91in the recess84of the inner shroud61into the region85of the radially inner side and the inner cavity86of the radially outer side. Of the two perforated plates103aand103b, the remaining perforated plate103bis a downstream perforated plate that partitions a portion located upstream from the retainer91, a portion in the retainer opening92, and a portion located downstream from the retainer91in the recess84of the inner shroud61into the region85of the radially inner side and the inner cavity86of the radially outer side.

In the above embodiment, the single impingement plate101that is long in the axial direction Da needs to be mounted on the inner shroud61after being inserted into the retainer opening92. For this reason, it may take considerable effort to mount the impingement plate101on the inner shroud61due to a mounting structure between the inner shroud61and the impingement plate101.

The present modification is designed to deal with cases requiring such effort. In the case of the present modification, first, the downstream perforated plate103band the upstream perforated plate103aare temporarily mounted on the inner shroud61. Next, the downstream perforated plate103band the upstream perforated plate103aare joined in one body by, for instance, welding, and these are used as the single impingement plate101a. Afterwards, if necessary, the single impingement plate101ais duly mounted on the inner shroud61.

In the present modification, the impingement plate101of the above embodiment is modified. However, like the present modification, in the first modification, too, two perforated plates may be joined in one body, and these may be used as one impingement plate.

INDUSTRIAL APPLICABILITY

In an aspect of the present invention, it is possible to increase the durability of the vane.

REFERENCE SIGNS LIST