Turbine stationary blade and gas turbine

Abstract

A turbine stationary blade according to at least one embodiment of the present disclosure comprises: an airfoil part; a shroud that is connected to an end of the airfoil part on one side in a blade height direction and that has an internal passage in a peripheral edge portion; and an insert that is disposed inside a cavity extending in the blade height direction in the airfoil part and that has a cylindrical shape. The cavity includes a first cavity and a second cavity different from the first cavity. The insert includes a first insert disposed inside the first cavity and a second insert disposed inside the second cavity. The turbine stationary blade comprises: a closing plate that closes an opening at one side end of the first cavity; and a lid member that is disposed at a position which is away from the closing plate toward the one side and away from an opening at one side end of the second cavity toward the one side.

Description

Turbine stator blade, and gas turbine

[0001] This disclosure relates to a turbine stator blade and a gas turbine. This application claims priority based on Japanese Patent Application No. 2025-018260 filed with the Japan Patent Office on February 6, 2025, the content of which is incorporated herein by reference.

[0002] The turbine stator blades and turbine rotor blades of a gas turbine are exposed to high-temperature combustion gas. Therefore, the turbine stator blades and turbine rotor blades need to be cooled by cooling air. For example, in the turbine stator blade described in Patent Document 1, the inner surface of the stator blade body is configured to be impingement-cooled. For example, in the turbine stator blade described in Patent Document 1, in order to be used for cooling the shrouds arranged on one side and the other side in the blade height direction, the cooling air after impingement-cooling the inner surface of the stator blade body is configured to be guided to an end flow path provided at the end of the shroud. Thus, the turbine stator blade described in Patent Document 1 is configured to effectively utilize the cooling air.

[0003] International Publication No. 2023 / 171752

[0004] However, in the turbine stator blade described in Patent Document 1, a specific configuration for guiding the cooling air after impingement-cooling the inner surface of the stator blade body to the end flow path of the shroud is not disclosed.

[0005] In view of the above circumstances, at least one embodiment of this disclosure aims to effectively utilize the cooling air in the turbine stator blade.

[0006] (1) A turbine stator blade according to at least one embodiment of the present disclosure comprises: an airfoil portion; a shroud connected to one end of the airfoil portion in the blade height direction and having an internal passage at its periphery; and a cylindrical insert disposed inside a cavity in the airfoil portion that extends in the blade height direction, wherein the cavity comprises a first cavity and a second cavity different from the first cavity; the insert comprises a first insert disposed inside the first cavity and a second insert disposed inside the second cavity; a closing plate defining at least a portion of the one end of the first cavity; and a lid member disposed at a position away from the closing plate to the one side and at a position away from the opening of the one end of the second cavity to the one side; wherein the second cavity and the internal passage communicate with the space defined by the closing plate and the lid member.

[0007] (2) A gas turbine according to at least one embodiment of the present disclosure comprises: a compressor for compressing air; a combustor for burning a mixture of air and fuel compressed by the compressor to produce combustion gas; and a turbine having a plurality of turbine stator blades having the configuration of (1) above, and generating rotational driving force from the combustion gas.

[0008] According to at least one embodiment of this disclosure, cooling air can be effectively utilized in the turbine stator blades.

[0009] This is a diagram illustrating the configuration of a gas turbine according to the present disclosure. This is a view of the stator blade according to the present disclosure, from the pressure surface toward the negative pressure surface. This is a cross-sectional view taken along the line III-III in Figure 2. This is a cross-sectional view of a part of a plurality of protrusions provided on an insert inserted into the leading edge cavity. This is a schematic perspective view of a part of the insert inserted into the leading edge cavity. This is a diagram schematically showing a cross-section of the inner shroud and the airfoil near the inner shroud along the blade height direction from the leading edge to the trailing edge. This is an enlarged view of the leading edge region in Figure 6A. This is a schematic view taken along the line VII-VII in Figure 2. This is a perspective view of the leading edge cover member of the cover member, viewed from the radially outer to the radially inner. This is a schematic enlarged view of the cross-section taken along the line III-III in Figure 2, showing the leading edge region. This is a diagram schematically showing a cross-section of the outer shroud and the airfoil near the outer shroud along the blade height direction from the leading edge to the trailing edge. Figure 2 is a schematic view along the line XI-XI.

[0010] Hereinafter, several embodiments of this disclosure will be described with reference to the attached drawings. However, the dimensions, materials, shapes, relative arrangements, etc., of the components described as embodiments or shown in the drawings are not intended to limit the scope of this disclosure, but are merely illustrative examples. For example, expressions describing relative or absolute arrangements such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" should not only describe such arrangements strictly, but also represent states where there are tolerances or relative displacements of an angle or distance sufficient to achieve the same function. For example, expressions describing things being in an equal state such as "identical," "equal," and "homogeneous" should not only describe states where things are strictly equal, but also represent states where there are tolerances or differences sufficient to achieve the same function. For example, expressions describing shapes such as square or cylindrical should not only describe geometrically precise square or cylindrical shapes, but also shapes including concave and concave parts, chamfered parts, etc., to the extent that the same effect can be achieved. On the other hand, expressions such as "to possess," "to be equipped with," "to have," "to include," or "to have" a single component are not exclusive expressions that exclude the existence of other components.

[0011] Figure 1 is a diagram illustrating the configuration of a gas turbine according to the present disclosure. As shown in Figure 1, the gas turbine 1 comprises a compressor 2 for generating compressed air, a combustor 4 for generating combustion gas using the compressed air and fuel, and a turbine 6 configured to be rotationally driven by the combustion gas. In the case of a gas turbine 1 for power generation, a generator (not shown) is connected to the turbine 6.

[0012] The compressor 2 includes a plurality of stationary vanes 16 fixed to the compressor casing 10 and a plurality of rotor blades 18 attached to the rotor 8. Air taken in from the air intake 12 is supplied to the compressor 2, and this air is compressed by passing through the plurality of stationary vanes 16 and the plurality of rotor blades 18 to become high-temperature, high-pressure compressed air.

[0013] The combustor 4 is supplied with fuel and compressed air generated by the compressor 2. The fuel and compressed air are mixed and then burned in the combustor 4 to produce combustion gas, which is the working fluid for the turbine 6. Multiple combustors 4 may be arranged within the casing 20 along the circumferential direction with the rotor 8 at its center.

[0014] The turbine 6 has a combustion gas passage 28 formed within the turbine casing 22, and includes a plurality of turbine stator blades 24 and turbine rotor blades 26 provided in the combustion gas passage 28. The stator blades 24 are fixed to the turbine casing 22, and a plurality of stator blades 24 arranged along the circumferential direction of the rotor 8 constitute a stator blade row. The rotor blades 26 are attached to the rotor 8, and a plurality of rotor blades 26 arranged along the circumferential direction of the rotor 8 constitute a rotor blade row. The stator blade row and the rotor blade row are arranged alternately in the axial direction of the rotor 8.

[0015] In the following explanation, the direction in which the axis Ax of the rotor 8 extends is referred to as the axial direction Da, the circumferential direction Dc is referred to as the circumferential direction Dc, and the direction perpendicular to the axis Ax of the rotor 8 is referred to as the radial direction Dr. The radial direction Dr is also called the blade height direction h.

[0016] Figure 2 is a view of the stator vane 24 according to the present disclosure, viewed from the pressure surface toward the negative pressure surface. As shown in Figure 2, the stator vane 24 includes a wing wall 34 that constitutes an airfoil portion 25. The wing wall 34 extends from the hub side edge 24a of the stator vane 24 toward the tip side edge 24b, that is, from one side to the other in the wing height direction h of the airfoil portion 25. An outer shroud 140 and an inner shroud 40 are provided on the tip side edge 24b and the hub side edge 24a, respectively. The wing wall 34 has a leading edge 43 and a trailing edge 49 that extend along the wing height direction h, and also has a pressure surface 46 and a negative pressure surface 48 that extend between the leading edge 43 and the trailing edge 49.

[0017] As will be described later, a cavity 50 (see Figure 3) is formed inside the airfoil portion 25 according to one embodiment, and a path 37 is formed in each of the outer shroud 140 and the inner shroud 40 that connects the outside of the stator vane 24 to the cavity 50. The path 37 is formed in the outer shroud 140. The role of the path 37 will be described later.

[0018] Figure 3 is a cross-sectional view taken along the line III-III in Figure 2. As shown in Figure 3, the airfoil portion 25 according to one embodiment is provided with a plurality of inserts 51 that are arranged inside the cavity 50, extend in the airfoil height direction h, and have a cylindrical shape. For example, the airfoil portion 25 according to one embodiment includes an A insert 51a, a B insert 51b, and a C insert 51c, which are arranged in order from the leading edge 43 side. A cavity 50 is formed inside the airfoil portion 25 according to one embodiment. The cavity 50 is divided into a plurality of cavities 50 by an intermediate wall (partition wall) 57, for example, three cavities 50: an A cavity 50a, a B cavity 50b, and a C cavity 50c, which are arranged in order from the leading edge 43 side. In one embodiment of the airfoil section 25, the A insert 51a is located in the A cavity 50a, the B insert 51b is located in the B cavity 50b, and the C insert 51c is located in the C cavity 50c. The number of cavities 50 formed inside the airfoil section 25 may be four or more.

[0019] <Insert Structure> Each of the inserts 51a, 51b, and 51c has a bottomed shape with an open end on the radially outer side Dr (not shown). That is, each of the inserts 51a, 51b, and 51c has a shape that follows the blade height direction h of the stator vane 24 (the direction perpendicular to the plane of the paper in Figure 3), and an internal cavity, which is an insert internal flow channel 56 (56a, 56b, 56c), is formed inside each of them. Each of the inserts 51a, 51b, and 51c is formed, for example, by additive manufacturing. Each of the inserts 51a, 51b, and 51c is an additively manufactured cylindrical body 61 formed in a cylindrical shape from a plate-like member 60 that extends in the blade height direction h.

[0020] For example, in each of the inserts 51a, 51b, and 51c, the plate-shaped member 60 has a flat plate portion 58 that extends linearly in a cross section perpendicular to the wing height direction h, that is, in a cross section parallel to the plane of paper in Figure 3, and an uneven plate portion 62 in the above cross section, which has a plurality of protruding portions 52 formed thereon that project toward the inner surface 34a of the wing wall 34, which is the inner wall surface of the cavity 50, from the outer surface 56ws of the wall portion 56w that defines the internal flow channels 56 (56a, 56b, 56c) inside the insert surrounded by the plate-shaped member 60.

[0021] For example, each of the inserts 51a, 51b, and 51c has a plurality of protrusions 52 that project toward the inner surface 34a of the wing wall 34. In each of the inserts 51a, 51b, and 51c, the plurality of protrusions 52 extend along the wing height direction h of the stator vane 24, and are formed so that adjacent protrusions 52 are spaced apart along the inner surface 34a when viewed from the wing height direction h.

[0022] In one embodiment of the stator vane 24, a cavity channel 53 is formed inside the cavities 50a, 50b, and 50c, defined by two adjacent protrusions 52 from among a plurality of protrusions 52 and the inner surface 34a of the wing wall 34, which is the inner wall surface of the cavities 50a, 50b, and 50c.

[0023] The path 37 (see Figure 2) is in communication with the respective insert internal flow paths 56a, 56b, and 56c in each of the cavities 50a, 50b, and 50c.

[0024] Next, the configuration of the protrusion 52 will be described. Figure 4 is a cross-sectional view of some of the multiple protrusions provided on the insert inserted into the leading edge cavity. Figure 5 is a schematic perspective view of a part of the insert inserted into the leading edge cavity. The configuration of the protrusion 52 of insert A 51a, which will be described below with reference to Figures 4 and 5, also applies to all or some of the multiple protrusions 52 provided on the other inserts 51b and 51c.

[0025] The protruding portion 52 has a plurality of cooling holes 55 that communicate with the internal flow path 56a of the insert and open to face the inner surface 34a of the wing wall 34. In the inserts 51a, 51b, and 51c according to this disclosure, the cooling holes 55 are formed at the tip 52a of the protruding portion 52, which is located away from the internal flow path 56a of the insert. The internal flow path 56 inside the protruding portion 52 is also referred to as the internal flow path 54 of the protrusion.

[0026] As described above, the protrusion 52 has a shape that extends along the blade height direction h of the stator vane 24, that is, along the direction perpendicular to the plane of paper in Figure 4, as shown in Figure 5. For this reason, for example, a plurality of cooling holes 55 are formed in the protrusion 52 at intervals from one another along this direction.

[0027] In the stator vane 24 configured in this way according to one embodiment, when cooling air for cooling the stator vane 24 is supplied to the path 37, the cooling air is distributed to the internal insert passages 56a, 56b, and 56c of each insert 51a, 51b, and 51c, and flows into the internal insert passages 56a, 56b, and 56c from an opening (not shown) radially outside the internal insert passages 56a, 56b, and 56c. The cooling air that has flowed into the internal insert passages 56a, 56b, and 56c is blown out from the cooling holes 55 of each protrusion 52 toward the inner surface 34a of the wing wall 34. As a result, the airfoil portion 25 is impinged and cooled from the inside.

[0028] <Configuration of the inner shroud> In one embodiment, the stator vane 24 is configured to effectively utilize the cooling air after impingement cooling of the airfoil portion 25 within each cavity 50a, 50b, and 50c, so as described below, the inner shroud 40 and the outer shroud 140 can be cooled with the cooling air after impingement cooling of the airfoil portion 25. Figure 6A is a schematic diagram showing a cross-section of the inner shroud and the airfoil portion near the inner shroud along the wing height direction from the leading edge to the trailing edge. Figure 6B is an enlarged view of the leading edge region of Figure 6A. Figure 7 is a schematic view along the VII-VII arrow in Figure 2. Note that in Figure 7, the description of the internal structure appearing in the cross-section along the VII-VII arrow of the airfoil portion is omitted and hatched.

[0029] In one embodiment of the stator vane 24, the inner shroud 40 includes a plate-shaped inner shroud body 41 extending in the circumferential direction Dc and the axial direction Da. In one embodiment of the inner shroud 40, a circumferential wall portion 42 protrudes inward in the radial direction Dr from a surface 41b opposite to the gas path surface 41a in the vane height direction h (inward in the radial direction Dr). The circumferential wall portion 42 extends along the extending direction of the ends at one and the other ends in the circumferential direction Dc and the upstream and downstream ends in the axial direction Da, and protrudes from the inner surface 41b in the radial direction Dr of the inner shroud body 41.

[0030] In one embodiment of the inner shroud 40, an internal passage 44 is formed inside the peripheral wall portion 42, extending in the circumferential direction Dc and the radial direction Dr, which are the extending directions of the peripheral wall portion 42. The internal passage 44 includes a front edge side internal passage 44L and a rear edge side internal passage 44T.

[0031] The leading edge internal passage 44L includes an upstream circumferential internal passage 45L and a pair of upstream axial internal passages 46L. The upstream circumferential internal passage 45L is an internal passage 44 that extends in the circumferential direction Dc upstream of the airfoil portion 25 in the axial direction Da of the circumferential wall portion 42, which is formed to surround the inner surface 41b in the radial direction Dr of the inner shroud body 41.

[0032] The pair of upstream axial internal passages 46L are formed within the peripheral wall portion 42 that extends axially in Da at one end in the circumferential direction Dc and the other end of the peripheral wall portion 42 that surrounds the inner surface 41b in the radial direction Dr of the inner shroud body 41, and are a pair of internal passages 44 that extend from the upstream side to the downstream side in the axial direction Da. The upstream ends of the pair of upstream axial internal passages 46L in the axial direction Da are connected to one end in the circumferential direction Dc or the other end of the upstream circumferential internal passage 45L, respectively.

[0033] The inlet portion 45Li of the upstream circumferential internal passage 45L is connected to the leading edge space 75L of the space 75, which will be described later. The outlet portions 46Lo of the pair of upstream axial internal passages 46L open to the side surfaces facing the radially inner surface 41b of the inner shroud body 41, in the circumferential wall portion 42 that extends in the axial direction Da at one end of the circumferential wall portion 42 that surrounds the radially inner surface 41b of the inner shroud body 41, and at the other end of the circumferential wall portion 42 that extends in the axial direction Da at one end of the circumferential wall portion 42 that surrounds the radially inner surface 41b of the inner shroud body 41, in the radial wall portion 42.

[0034] The trailing edge internal passage 44T includes a downstream circumferential internal passage 45T and a pair of downstream axial internal passages 46T. The downstream circumferential internal passage 45T is an internal passage 44 that extends in the circumferential direction Dc downstream of the airfoil portion 25, within the circumferential wall portion 42 formed to surround the inner surface 41b in the radial direction Dr of the inner shroud body 41.

[0035] The pair of downstream axial internal passages 46T are formed within the peripheral wall portion 42 that extends axially in Da at one end in the circumferential direction Dc and the other end of the peripheral wall portion 42 that surrounds the inner surface 41b in the radial direction Dr of the inner shroud body 41, and are a pair of internal passages 44 that extend from the downstream side to the upstream side in the axial direction Da. The downstream ends of the pair of downstream axial internal passages 46T in the axial direction Da are connected to one end in the circumferential direction Dc or the other end of the downstream circumferential internal passage 45T, respectively.

[0036] The inlet portion 45Ti of the downstream circumferential internal passage 45T is connected to the trailing edge space 75T within the space 75 described later. The outlet portions 46To of the pair of downstream axial internal passages 46T are open on the side surfaces facing the radially inner surface 41b of the inner shroud body 41, in the circumferential wall portion 42 that extends in the axial direction Da at one end of the circumferential wall portion 42 that surrounds the radially inner surface 41b of the inner shroud body 41, and at the other end of the circumferential wall portion 42 that extends in the axial direction Da at one end of the circumferential wall portion 42 that surrounds the radially inner surface 41b of the inner shroud body 41.

[0037] In one embodiment of the stator vane 24, each cavity 50a, 50b, 50c has an opening 50io at its radially inner end 50i that opens onto the radially inner surface 41b of the inner shroud body 41. In one embodiment of the stator vane 24, a closing plate 71 is positioned at one end of the first cavity 50a in the wing height direction h (radially inner). That is, at least a portion of the end of the first cavity 50a in the wing height direction h (radially inner) is defined and closed by the closing plate 71.

[0038] In one embodiment, the stationary vane 24 is positioned radially inward from the closing plate 71 and includes a cover member 73 positioned radially inward from the closing plate 71 and covering the openings 50io at the ends 50i of each cavity 50a, 50b, and 50c, as well as the openings 50io at the ends 50i of the ends 50i of the cavity A 50a and the cavity B 50b when viewed from radially inward, and a rear edge cover member 73T positioned radially inward from the end 50i of the cavity C 50c when viewed from radially inward,

[0039] As described above, the lid member 73 is positioned radially inward by Dr from the closing plate 71. Therefore, a space 75 is formed between the closing plate 71 and the lid member 73. The lid member 73 separates the space 75 between the closing plate 71 and the lid member 73, i.e., the space 75 defined by the closing plate 71 and the lid member 73, from the space on the opposite side of the lid member 73 from the space 75. The space 75 defined by the closing plate 71 and the lid member 73 is separated by a partition wall 57 that separates the B cavity 50b and the C cavity 50c. The space 75 defined by the closing plate 71 and the lid member 73 includes a front edge side space 75L on the front edge 43 side of the partition wall 57 that separates the B cavity 50b and the C cavity 50c, and a rear edge side space 75T on the rear edge 49 side of the partition wall 57.

[0040] In one embodiment of the stator vane 24, the leading edge space 75L is surrounded by the inner surface 41b of the inner shroud body 41 in the radial direction Dr, a closing plate 71 positioned at the radially inner end of the A cavity 50a, a leading edge cover member 73L, a circumferential wall portion 42 extending in the circumferential direction Dc upstream of the airfoil portion 25 in the axial direction Da within the circumferential wall portion 42, and a circumferential wall portion 42 extending in the axial direction Da at one end and the other end in the circumferential direction Dc, and a partition wall 57 separating the A cavity 50a and the B cavity 50b.

[0041] In one embodiment of the stator vane 24, the trailing edge space 75T is surrounded by the inner surface 41b of the inner shroud body 41 in the radial direction Dr, the trailing edge cover member 73T, a circumferential wall portion 42 that extends in the circumferential direction Dc downstream of the airfoil portion 25 in the axial direction Da, and a circumferential wall portion 42 that extends in the axial direction Da at one end and the other end of the circumferential direction Dc, and a partition wall 57 that separates the A cavity 50a and the B cavity 50b.

[0042] In one embodiment of the stator vane 24, the B cavity 50b and the internal passage 44 communicate with the space 75 defined by the closing plate 71 and the cover member 73. Similarly, in one embodiment of the stator vane 24, the C cavity 50c and the internal passage 44 communicate with the space 75 defined by the closing plate 71 and the cover member 73. More specifically, the B cavity 50b and the upstream circumferential internal passage 45L communicate with the front edge space 75L between the closing plate 71 that closes the opening 50io at the end 50i of the A cavity 50a and the front edge cover member 73L. The C cavity 50c and the downstream circumferential internal passage 45T communicate with the rear edge space 75T.

[0043] In the stator vane 24 configured in this way according to one embodiment, when cooling air for cooling the stator vane 24 is supplied to the path 37, the cooling air is blown out from the cooling holes 55 in each insert 51a, 51b, 51c toward the inner surface 34a of the wing wall 34, thereby impinging and cooling the airfoil portion 25 from the inside. After the cooling air has been blown out from the cooling holes 55 of the first cavity 50a, whose end opening 50io is closed by the closing plate 71, and impinges and cools the airfoil portion 25 from the inside, the cooling air flows radially outward in the cavity flow path 53 defined by two adjacent protrusions 52 among the plurality of protrusions 52 and the inner surface 34a of the wing wall 34, which is the inner wall surface of the first cavity 50a.

[0044] In the B cavity 50b and C cavity 50c, where the closing plate 71 is not provided, the cooling air that is ejected from the cooling holes 55 and impinges the airfoil portion 25 from the inside flows radially inward through the cavity passage 53 and flows into the space 75 defined by the closing plate 71 and the lid member 73 through the opening 50io at the end 50i. That is, the cooling air that flows radially inward through the cavity passage 53 of the B cavity 50b flows into the leading edge space 75L between the closing plate 71 and the lid member 73 through the opening 50io at the end 50i of the B cavity 50b. Similarly, the cooling air that flows radially inward through the cavity passage 53 of the C cavity 50c flows into the trailing edge space 75T through the opening 50io at the end 50i of the C cavity 50c.

[0045] The cooling air flowing into the leading-edge side space 75L flows into the upstream circumferential internal passage 45L from the inlet portion 45Li of the upstream circumferential internal passage 45L. The cooling air flowing into the upstream circumferential internal passage 45L flows through the upstream circumferential internal passage 45L while cooling the circumferential wall portion 42 formed so as to surround the periphery of the inner surface 41b on the inner side in the radial direction Dr of the inner shroud body 41, and extends in the circumferential direction Dc on the upstream side in the axial direction Da from the airfoil portion 25. Then it flows to one side and the other side in the circumferential direction Dc of the upstream circumferential internal passage 45L and flows into a pair of upstream axial internal passages 46L.

[0046] The cooling air flowing into the pair of upstream axial internal passages 46L flows through the pair of upstream axial internal passages 46L while cooling the circumferential wall portion 42 extending in the axial direction Da at the ends on one side and the other side in the circumferential direction Dc inside the circumferential wall portion 42 formed so as to surround the periphery of the inner surface 41b on the inner side in the radial direction Dr of the inner shroud body 41, and is ejected from the outlet portion 46Lo.

[0047] Although detailed description is omitted, the stator vane 24 according to one embodiment is configured to be able to impingement-cool a region that is located outside the airfoil portion 25 when viewed from the airfoil height direction h within the inner surface 41b on the inner side in the radial direction Dr of the inner shroud body 41 by the cooling air ejected from the outlet portion 46Lo. Therefore, the cooling air ejected from the outlet portion 46Lo impingement-cools the region in the inner shroud body 41.

[0048] The cooling air flowing into the trailing-edge side space 75T flows into the downstream circumferential internal passage 45T from the inlet portion 45Ti of the downstream circumferential internal passage 45T. The cooling air flowing into the downstream circumferential internal passage 45T flows through the downstream circumferential internal passage 45T while cooling the circumferential wall portion 42 extending in the circumferential direction Dc on the downstream side in the axial direction Da from the airfoil portion 25 inside the circumferential wall portion 42 formed so as to surround the periphery of the inner surface 41b on the inner side in the radial direction Dr of the inner shroud body 41, and flows into a pair of downstream axial internal passages 46T.

[0049] The cooling air that flows into the pair of downstream axial internal passages 46T cools the peripheral wall portion 42 that extends in the axial direction Da at one end in the circumferential direction Dc and the other end of the peripheral wall portion 42 that is formed to surround the inner surface 41b in the radial direction Dr of the inner shroud body 41, and flows through the pair of downstream axial internal passages 46T toward the upstream side in the axial direction Da, and is blown out from the outlet portion 46To.

[0050] Although a detailed explanation will be omitted, in one embodiment, the stator vane 24 is configured to impinge-cool a region of the inner surface 41b of the inner shroud body 41 in the radial direction Dr, which is located outside the airfoil portion 25 when viewed from the vane height direction h, by the cooling air blown out from the outlet 46To. Therefore, the cooling air blown out from the outlet 46To impinges-cools this region of the inner shroud body 41.

[0051] As described above, with the stator vane 24 according to one embodiment, the inner shroud 40 can be cooled with the cooling air after the airfoil portion 25 has been cooled from the inner surface in the B cavity 50b and C cavity 50c, thus enabling effective utilization of the cooling air. Furthermore, in a gas turbine 1 equipped with the stator vane 24 according to one embodiment, the cooling air can be effectively utilized in the stator vane 24, thereby improving the efficiency of the gas turbine 1.

[0052] In one embodiment of the stator vane 24, the closing plate 71 and the cover member 73 define a portion of the flow path for guiding cooling air from the opening 50io at one end 50i on one side (inward in the radial direction Dr) of the cavity 50 to the internal passage 44. That is, the closing plate 71 that closes the opening 50io at the end 50i of the A cavity 50a and the leading edge side cover member 73L define a portion of the flow path for guiding cooling air from the opening 50io at the radially inward end 50i of the B cavity 50b to the leading edge side internal passage 44L.

[0053] In one embodiment of the stator vane 24, the cavity passages 53 in the B cavity 50b and C cavity 50c communicate with the internal passage 44 via a space 75 defined by the closing plate 71 and the lid member 73. That is, in one embodiment of the stator vane 24, the cavity passages 53 in the B cavity 50b and C cavity 50c communicate with the leading edge side internal passage 44L via the leading edge side space 75L. In one embodiment of the stator vane 24, the cavity passages 53 in the C cavity 50c and C cavity 50c communicate with the trailing edge side internal passage 44T via the trailing edge side space 75T. As a result, the inner shroud 40 can be cooled with the cooling air after the airfoil portion 25 has been cooled from the inner surface in the B cavity 50b and C cavity 50c, thus enabling effective use of the cooling air.

[0054] <Regarding the position of the bottom of the insert> Since the closing plate 71 is not provided in the B cavity 50b and the C cavity 50c, the position of the bottom 59 of the insert 51 can be set radially inward compared to the A cavity 50a where the closing plate 71 is provided. Therefore, in the stator vane 24 according to one embodiment, the radially inward bottom 59 of the B insert 51b and the C insert 51c is located radially inward than the radially inward bottom 59 of the A insert 51a. As a result, the cooling holes 55 provided in the protruding portions 52 of the B insert 51b and the C insert 51c can be positioned as radially inward as possible, making it easier to cool the radially inward region of the airfoil portion 25.

[0055] <Regarding the position of the radially inward end of the bulkhead> In the stator vane 24 according to one embodiment, the position of the radially inward end 57i of the bulkhead 57 separating the B cavity 50b and the C cavity 50c is different from the position of the radially inward end 57i of the other bulkheads 57. That is, the position of the radially inward end 57i of the bulkhead 57 separating the B cavity 50b and the C cavity 50c is located radially inward than the position of the radially inward end 57i of the other bulkheads 57.

[0056] In one embodiment of the stator vane 24, the leading edge cover member 73L and the trailing edge cover member 73T are connected to a bulkhead 57 that separates the B cavity 50b and the C cavity 50c. This makes it relatively easy to connect the leading edge cover member 73L and the trailing edge cover member 73T to the airfoil portion 25.

[0057] <Positioning at the bottom of the insert> In the stationary vane 24 according to one embodiment, a recess 81 is formed at the bottom 59 of each insert 51a, 51b, 51c, into which a first fitting projection 83, described later, fits. The recess 81 is a recess that is recessed radially outward from the bottom 59 of each insert 51a, 51b, 51c. The closing plate 71 has a first fitting projection 83 that protrudes radially outward and fits into the recess 81 formed at the bottom 59 on the radially inward side of the insert 51. The lid member 73 has a second fitting projection 84 that protrudes radially outward and fits into the recess 81 formed at the bottom 59 on the radially inward side of the insert 51.

[0058] When the closing plate 71 is attached to the airfoil portion 25, the first fitting projection 83 fits into the recess 81 formed in the A insert 51a. This allows the A insert 51a to be positioned at the bottom 59 of the A insert 51a. Similarly, when the cover member 73 is attached to the airfoil portion 25, the second fitting projection 84 fits into the recess 81 formed in each insert 51b, 51c. This allows each insert 51b, 51c to be positioned at the bottom 59 of the A insert 51b, 51c.

[0059] This makes it easier to position the bottom 59 of the A insert 51a further inward in the radial direction Dr compared to a case where a projection is provided on the bottom 59 of the A insert 51a that protrudes radially outward, and a recess is provided in the closing plate 71 into which the projection fits. This allows the cooling holes 55 provided in the projection 52 of the A insert 51a to be positioned further inward in the radial direction Dr, making it easier to cool the region of the airfoil portion 25 that is further inward in the radial direction Dr. Similarly, this makes it easier to position the bottom 59 of each insert 51b, 51c further inward in the radial direction Dr compared to a case where a projection is provided on the bottom 59 of each insert 51b, 51c that protrudes radially outward, and a recess is provided in the lid member 73 into which the projection fits. This allows the cooling holes 55 provided in the protruding portions 52 of each insert 51b, 51c to be positioned radially inward (Dr), making it easier to cool the radially inward region of the airfoil portion 25.

[0060] <Positioning of the Cover Member> Figure 8 is a perspective view of the leading edge cover member of the cover member, viewed from the radially outer to the radially inner direction. Figure 9 is a schematic diagram of the cross section taken along the line III-III in Figure 2, enlarged for the leading edge region. In the stator vane 24 according to one embodiment, the cover member 73 has a contact projection 91 that protrudes radially outward Dr and abuts against the inner surface 34a of the wing wall 34, which is the inner wall surface of the cavity 50, and the side surface 57s of the bulkhead 57. Although Figures 8 and 9 only show the contact projection 91 provided on the leading edge cover member 73L, the contact projection 91 is also provided on the trailing edge cover member 73T, for example, as shown in Figures 6A and 6B. In the following description, the contact projection 91 provided on the leading edge cover member 73L will be mainly described, but unless otherwise specified, the same applies to the contact projection 91 provided on the trailing edge cover member 73T.

[0061] According to one embodiment of the stationary vane 24, by bringing the contact projection 91 into contact with the inner wall surface of the cavity 50, it becomes easier to position the cover member 73 relative to the airfoil portion 25 when connecting the cover member 73 to the airfoil portion 25.

[0062] The contact projection 91 has a cylindrical shape, for example, projecting radially outward from the radially outward surface 73s of the lid member 73. The contact projection 91 abuts against the inner surface 34a of the wing wall 34, which is the inner wall surface of the cavity 50, and the side surface 57s of the partition wall 57 with its cylindrical outer surface 92. This makes it easier to ensure the positioning accuracy of the lid member 73 relative to the wing-shaped portion 25.

[0063] For example, the abutment projection 91 provided on the leading edge cover member 73L, as shown in Figures 8 and 9, abuts against two surfaces: the leading edge 43 side surface 57s1 of the partition wall 57 separating the B cavity 50b and the C cavity 50c, which is the inner wall surface of the B cavity 50b, and the inner surface 34a of the wing wall 34 on the negative pressure surface 48 side. Alternatively, the abutment projection 91 provided on the leading edge cover member 73L may abut against two surfaces: the leading edge 43 side surface 57s1 of the partition wall 57 separating the B cavity 50b and the C cavity 50c, which is the inner wall surface of the B cavity 50b, and the inner surface 34a of the wing wall 34 on the pressure surface 46 side. Furthermore, the abutment projection 91 provided on the leading edge cover member 73L may abut against two surfaces: the inner wall surface of the B cavity 50b, which is the rear edge 49 side surface of the partition wall 57 separating the A cavity 50a and the B cavity 50b, and the inner surface 34a of the wing wall 34 on the pressure surface 46 side.

[0064] For example, the abutment projection 91 provided on the trailing edge cover member 73T may abut two surfaces: the inner wall surface of the C cavity 50c, which is the trailing edge 49 side surface of the partition wall 57 separating the B cavity 50b and the C cavity 50c, and the inner surface 34a of the wing wall 34 on the negative pressure surface 48 side. The abutment projection 91 provided on the trailing edge cover member 73T may abut two surfaces: the inner wall surface of the C cavity 50c, which is the trailing edge 49 side surface of the partition wall 57 separating the B cavity 50b and the C cavity 50c, and the inner surface 34a of the wing wall 34 on the pressure surface 46 side.

[0065] As described above, in the stationary vane 24 according to one embodiment, the abutment projection 91 abuts the inner surface 34a of the wing wall 34, which is the inner wall surface of the cavity 50, and the side surface 57s of the bulkhead 57 at two different points on the outer peripheral surface 92, positions P1 and P2, when viewed from the wing height direction h. This makes it easier to position the cover member 73 relative to the airfoil 25, thereby improving the positioning accuracy of the cover member 73 relative to the airfoil 25. For example, in the example shown in Figures 8 and 9, if position P1 is the contact position between the surface 57s1 on the leading edge 43 side of the bulkhead 57 separating the B cavity 50b and the C cavity 50c and the outer peripheral surface 92 of the abutment projection 91, then position P2 is the contact position between the inner surface 34a of the wing wall 34 on the negative pressure surface 48 side and the outer peripheral surface 92 of the abutment projection 91.

[0066] In one embodiment of the stationary vane 24, the contact projection 91 has a notch 94 in which a portion of the region furthest from the inner surface 34a of the vane wall 34, which is the inner wall surface of the B cavity 50b, and the side surface 57s of the partition wall 57 is cut out, when viewed from the vane height direction h. This reduces the volume of the contact protrusion 91 that protrudes from the opening 50io at the radially inner end 50i of the cavity 50 to the space 75 defined by the closing plate 71 and the lid member 73. This reduces the increase in pressure loss due to the contact protrusion 91 of the cooling air flowing from the opening 50io at the radially inner end 50i of the cavity 50 to the space 75 defined by the closing plate 71 and the lid member 73.

[0067] In one embodiment of the stator vane 24, as shown in Figure 9, when viewed from the vane height direction h, the cavity passage 53, which is the region sandwiched between two adjacent protrusions 52 among the plurality of protrusions 52, overlaps with at least a part of the notch 94. As a result, compared to the case where the notch 94 is not provided, the contact protrusion 91 is less likely to obstruct the flow of cooling air flowing from the cavity passage 53 into the space 75 defined by the closing plate 71 and the lid member 73.

[0068] <Outer Shroud Configuration> In the above-described embodiment, the configuration of the inner shroud 40 was mainly explained, but the outer shroud 140 may have the same configuration as the inner shroud 40 described above. Figure 10 is a schematic diagram showing a cross-section of the outer shroud and the airfoil portion near the outer shroud along the wing height direction from the leading edge to the trailing edge. Figure 11 is a schematic view of Figure 2 taken along the line XI-XI.

[0069] In the stator vane 24 according to another embodiment, the outer shroud 140 includes a plate-shaped outer shroud body 141 extending in the circumferential direction Dc and the axial direction Da. In the outer shroud 140 according to another embodiment, a circumferential wall portion 142 protrudes radially outward from the surface 141b opposite to the wing height direction h (outside in the radial direction Dr) from the gas pass surface 141a. The circumferential wall portion 142 extends along the extending direction of the ends at one and the other ends in the circumferential direction Dc and the upstream and downstream ends in the axial direction Da, and protrudes from the radially outward surface 141b of the outer shroud body 141. In the description of the above-mentioned embodiment, one side of the wing height direction h is on the inside of the radial direction Dr, and the other side of the wing height direction h is on the outside of the radial direction Dr. However, in the description of the other embodiment described below, one side of the wing height direction h is on the outside of the radial direction Dr, and the other side of the wing height direction h is on the inside of the radial direction Dr.

[0070] In the outer shroud 140 according to another embodiment, an internal passage 144 is formed inside the peripheral wall portion 142, extending in the circumferential direction Dc and the radial direction Dr, which are the extending directions of the peripheral wall portion 142. The internal passage 144 includes a front edge side internal passage 144L and a rear edge side internal passage 144T.

[0071] The leading edge internal passage 144L includes an upstream circumferential internal passage 145L and a pair of upstream axial internal passages 146L. The upstream circumferential internal passage 145L is an internal passage 144 that extends in the circumferential direction Dc upstream of the airfoil portion 25 in the axial direction Da within the circumferential wall portion 142 formed to surround the outer surface 141b in the radial direction Dr of the outer shroud body 141.

[0072] The pair of upstream axial internal passages 146L are formed within the peripheral wall portion 142 that extends axially in Da at one end in the circumferential direction Dc and the other end of the peripheral wall portion 142 that surrounds the outer surface 141b in the radial direction Dr of the outer shroud body 141, and are a pair of internal passages 144 that extend from the upstream side to the downstream side in the axial direction Da. The upstream ends of the pair of upstream axial internal passages 146L in the axial direction Da are connected to one end in the circumferential direction Dc or the other end of the upstream circumferential internal passage 145L, respectively.

[0073] The inlet portion 145Li of the upstream circumferential internal passage 145L is connected to the front edge space 176, which will be described later. The outlet portions 146Lo of the pair of upstream axial internal passages 146L are located in the circumferential wall portion 142 that is formed to surround the outer surface 141b of the outer shroud body 141 in the radial direction Dr, and extend in the axial direction Da at one end of the circumferential wall portion 142 in the circumferential direction Dc and the other end of the circumferential wall portion 142, and open to the side surface facing the outer surface 141b of the outer shroud body 141 in the radial direction Dr.

[0074] The trailing edge internal passage 144T includes a downstream circumferential internal passage 145T and a pair of downstream axial internal passages 146T. The downstream circumferential internal passage 145T is an internal passage 144 that extends in the circumferential direction Dc downstream of the airfoil portion 25, within the circumferential wall portion 142 formed to surround the outer surface 141b in the radial direction Dr of the outer shroud body 141.

[0075] The pair of downstream axial internal passages 146T are formed within the peripheral wall portion 142 that extends axially in Da at one end in the circumferential direction Dc and the other end of the peripheral wall portion 142 that surrounds the outer surface 141b in the radial direction Dr of the outer shroud body 141, and are a pair of internal passages 144 that extend from the downstream side to the upstream side in the axial direction Da. The downstream ends of the pair of downstream axial internal passages 146T in the axial direction Da are connected to one end in the circumferential direction Dc or the other end of the downstream circumferential internal passage 145T, respectively.

[0076] The inlet portion 145Ti of the downstream circumferential internal passage 145T is connected to the trailing edge space 175T, which will be described later. The outlet portions 146To of the pair of downstream axial internal passages 146T are located in the circumferential wall portion 142 that is formed to surround the outer surface 141b of the outer shroud body 141 in the radial direction Dr, and open to the side surface facing the outer surface 141b of the outer shroud body 141, at the circumferential wall portion 142 that extends in the axial direction Da at one end in the circumferential direction Dc and the other end in the circumferential direction Dc.

[0077] In the stator vane 24 according to the other embodiment, each cavity 50a, 50b, 50 has an opening 150io at its radially outer end 150i that opens to the radially outer surface 141b of the outer shroud body 141. In the stator vane 24 according to the other embodiment, a closing plate 171 is positioned at one end of the C cavity 50c in the wing height direction h (radially outward in the Dr direction). That is, at least a portion of the end of the C cavity 50c in the wing height direction h (radially outward in the Dr direction) is defined and closed by the closing plate 171. In the stator vane 24 according to the other embodiment, the C insert 51c penetrates the closing plate 171 radially in the Dr direction. The closing plate 171 may be formed, for example, as part of the C insert 51c.

[0078] In another embodiment, the stator vane 24 is positioned radially outward from the closing plate 171 and includes a cover member 173 positioned radially outward from the closing plate 171, and covering the opening 150io of the end 150i of each cavity 50a, 50b, 50c, and radially outward from the closing plate 171. The cover member 173 is positioned to cover the C cavity 50c when viewed radially outward. In the other embodiment, the stator vane 24 may also be formed as part of the B insert 51b at the radially outward end of the B insert 51b.

[0079] In the stationary vane 24 according to another embodiment, the cover member 173 has a through hole 173a that penetrates the cover member 173 in the radial direction Dr. The open end 51oe on the radially outer side of the C insert 51c is inserted through the through hole 173a.

[0080] As described above, the lid member 173 is positioned radially outward by Dr from the closing plate 171. Therefore, a rear edge space 175T is formed between the closing plate 171 and the lid member 173. The lid member 173 separates the rear edge space 175T between the closing plate 171 and the lid member 173, that is, the rear edge space 175T defined by the closing plate 171 and the lid member 173, from the space on the opposite side of the lid member 173 from the rear edge space 175T.

[0081] In the stator vane 24 according to another embodiment, the trailing edge space 175T is surrounded by the radially outer surface 141b of the outer shroud body 141, a circumferential wall portion 42 that extends in the circumferential direction Dc downstream of the airfoil portion 25 in the axial direction Da, and a circumferential wall portion 42 that extends in the axial direction Da at one end and the other end of the circumferential direction Dc, and a partition wall 57 that separates the A cavity 50a and the B cavity 50b.

[0082] In the stationary vane 24 according to another embodiment, the B cavity 50b and the internal passage 144 (downstream circumferential internal passage 145T) are in communication with the trailing edge space 175T defined by the closing plate 171 and the cover member 173.

[0083] In another embodiment, the stator vane 24 has a cover portion 177 positioned radially outward from the outer surface 141b of the outer shroud body 141 in the radial direction Dr, and from the opening 150io of the end 150i of the A cavity 50a. The cover portion 177 is positioned to cover the A cavity 50a when viewed from the radial direction Dr outward. In the other embodiment, the cover portion 177 may be formed as part of the A insert 51a at the radially outward end of the A insert 51a.

[0084] As described above, the lid portion 177 is positioned radially outward from the outer surface 141b of the outer shroud body 141 in the radial direction Dr, and from the opening 150io of the end 150i of the A cavity 50a. Therefore, a front edge space 176 is formed between the outer surface 141b of the outer shroud body 141 in the radial direction Dr and the lid portion 177. The lid portion 177 separates the front edge space 176 between the outer surface 141b of the outer shroud body 141 in the radial direction Dr and the lid portion 177, that is, the front edge space 176 defined by the outer surface 141b of the outer shroud body 141 in the radial direction Dr and the lid portion 177, from the space on the opposite side of the lid portion 177 from the front edge space 176.

[0085] In the stator vane 24 according to another embodiment, the leading edge space 176 is surrounded by the radially outer surface 141b of the outer shroud body 141, the cover portion 177, the circumferential wall portion 142 that extends in the circumferential direction Dc upstream of the airfoil portion 25 in the axial direction Da, and the circumferential wall portion 142 that extends in the axial direction Da at one end and the other end of the circumferential direction Dc, and the partition wall 57 that separates the A cavity 50a and the B cavity 50b.

[0086] In the stator vane 24 of the other embodiment configured in this way, when cooling air for cooling the stator vane 24 is supplied to the path 37, as described above, the cooling air is blown out from the cooling holes 55 in each insert 51a, 51b, 51c toward the inner surface 34a of the wing wall 34, thereby impinging the airfoil portion 25 from the inside. After the cooling air has been blown out from the cooling holes 55 of the first cavity 50a, whose end opening 50io is closed by the closing plate 71, and impinges the airfoil portion 25 from the inside, the cooling air flows radially outward Dr through the cavity internal flow path 53 defined by two adjacent protrusions 52 among the plurality of protrusions 52 and the inner surface 34a of the wing wall 34, which is the inner wall surface of the first cavity 50a as described above, and flows into the leading edge space 176.

[0087] The cooling air that flows into the leading edge space 176 flows into the upstream circumferential internal passage 145L from the inlet 145Li of the upstream circumferential internal passage 145L. The cooling air that flows into the upstream circumferential internal passage 145L cools the circumferential wall portion 142 that extends in the circumferential direction Dc upstream of the airfoil portion 25 in the axial direction Da of the outer surface 141b of the outer shroud body 141, and flows into one side and the other side of the circumferential direction Dc along the upstream circumferential internal passage 145L, and flows into a pair of upstream axial internal passages 146L.

[0088] The cooling air that flows into the pair of upstream axial internal passages 146L cools the peripheral wall portion 142 that extends in the axial direction Da at one end in the circumferential direction Dc and the other end of the peripheral wall portion 142 that is formed to surround the outer surface 141b in the radial direction Dr of the outer shroud body 141, and flows through the pair of upstream axial internal passages 146L toward the downstream side in the axial direction Da, and is blown out from the outlet portion 146Lo.

[0089] Although a detailed explanation will be omitted, in other embodiments, the stator vane 24 is configured to impinge-cool a region of the outer surface 141b of the outer shroud body 141 in the radial direction Dr, which is located outside the airfoil portion 25 when viewed from the vane height direction h, by the cooling air blown out from the outlet 146Lo. Therefore, the cooling air blown out from the outlet 146Lo impinges-cools that region of the outer shroud body 141.

[0090] In the B cavity 50b, a portion of the cooling air that has been ejected from the cooling holes 55 and impinged the airfoil portion 25 from the inside flows radially outward through the cavity internal flow path 53 and flows into the trailing edge space 175T defined by the closing plate 171 and the lid member 173 through the opening 150io at the end 150i. In other words, the cooling air that has flowed radially outward through the cavity internal flow path 53 of the B cavity 50b flows into the trailing edge space 175T between the closing plate 171 and the lid member 173 through the opening 150io at the end 150i of the B cavity 50b.

[0091] The cooling air that flows into the trailing edge space 175T flows into the downstream circumferential internal passage 145T from the inlet 145Ti of the downstream circumferential internal passage 145T. The cooling air that flows into the downstream circumferential internal passage 145T cools the circumferential wall portion 142 that extends in the circumferential direction Dc downstream of the airfoil portion 25 in the axial direction Da, within the circumferential wall portion 142 formed to surround the outer surface 141b in the radial direction Dr of the outer shroud body 141, and flows into one side and the other side of the downstream circumferential direction Dc in the downstream circumferential internal passage 145T, and flows into a pair of downstream axial internal passages 146T.

[0092] The cooling air that flows into the pair of downstream axial internal passages 146T cools the peripheral wall portion 142 that extends in the axial direction Da at one end in the circumferential direction Dc and the other end of the peripheral wall portion 142 that is formed to surround the outer surface 141b in the radial direction Dr of the outer shroud body 141, and flows through the pair of downstream axial internal passages 146T toward the upstream side in the axial direction Da, and is blown out from the outlet portion 146To.

[0093] Although a detailed explanation will be omitted, in other embodiments, the stator vane 24 is configured to impinge-cool a region of the outer surface 141b of the outer shroud body 141 in the radial direction Dr, which is located outside the airfoil portion 25 when viewed from the vane height direction h, by the cooling air blown out from the outlet 146To. Therefore, the cooling air blown out from the outlet 146To impinges-cools this region of the outer shroud body 141.

[0094] As described above, according to the stator vane 24 of this other embodiment, the outer shroud 140 can be cooled with the cooling air after the airfoil portion 25 has been cooled from the inner surface in the B cavity 50b, thus enabling effective use of the cooling air. Furthermore, in the gas turbine 1 equipped with the stator vane 24 of this other embodiment, the cooling air can be effectively utilized in the stator vane 24, thereby improving the efficiency of the gas turbine 1.

[0095] In the stator vane 24 according to another embodiment, the closing plate 171 and the cover member 173 define a part of the flow path for guiding cooling air from the opening 150io at one end 150i on one side (radially outward in the height direction h) of the cavity 50 (the B cavity 50b) to the internal passage 144. That is, the closing plate 171 and the cover member 173 that close the opening 150io at the end 150i of the C cavity 50c define a part of the flow path for guiding cooling air from the opening 150io at the radially outward end 150i of the B cavity 50b to the trailing edge side internal passage 144T.

[0096] In the stator vane 24 according to another embodiment, the cavity passage 53 in the B cavity 50b communicates with the internal passage 144 via the trailing edge space 175T defined by the closing plate 171 and the lid member 173. That is, in the stator vane 24 according to another embodiment, the B cavity 50b communicates with the trailing edge internal passage 144T via the trailing edge space 175T. As a result, the cooling air after the airfoil portion 25 has been cooled from the inner surface in the B cavity 50b can be used to cool the outer shroud 140, thus enabling effective use of the cooling air.

[0097] This disclosure is not limited to the embodiments described above, and includes modified forms of the embodiments described above, as well as forms that combine these forms as appropriate. For example, in the embodiments described above, the inner shroud 40 of the stator vane 24 mainly has three inserts 51, but the stator vane 24 may have four cavities 50 and four inserts 51. For example, an insert (let's call it the D insert) located on the trailing edge 49 side of the C insert 51c may have the same configuration as the A insert 51a, and the trailing edge space 75T may be determined by the closing plate 71 and the trailing edge cover member 73T of the D insert. That is, a cavity 50 is provided on the trailing edge 49 side of the C cavity 50c in the airfoil portion 25, and the configuration on the trailing edge 49 side of the partition wall 57 separating the B cavity 50b and the C cavity 50c may have the same configuration as the configuration on the leading edge 43 side of the partition wall 57. The stator vane 24 may have five or more cavities 50 and five or more inserts 51. Furthermore, for example, the stator vane 24 may include both the inner shroud 40 according to one embodiment described above and the outer shroud 140 according to another embodiment.

[0098] Furthermore, in the above-described embodiment, the B cavity 50b was configured to communicate with the internal passage 44 of the inner shroud 40, but instead of the B cavity 50b, the A cavity 50a may be configured to communicate with the internal passage 44 of the inner shroud 40.

[0099] The contents described in each of the above embodiments can be understood, for example, as follows: (1) A turbine stator blade 24 according to at least one embodiment of the present disclosure comprises an airfoil portion 25, a shroud (inner shroud 40 in one embodiment, outer shroud 140 in other embodiments) connected to one end of the airfoil portion 25 in the airfoil height direction h (inner radial Dr in one embodiment, outer radial Dr in other embodiments) and having an internal passage (inner passage 44 in one embodiment, inner passage 144 in other embodiments) at its periphery, and an insert 51 which is disposed inside a cavity 50 extending in the airfoil height direction h in the airfoil portion 25, extends in the airfoil height direction h, and has a cylindrical shape. Cavity 50 includes a first cavity (cavity A 50a in one embodiment, cavity C 50c in other embodiments) and a second cavity different from the first cavity (cavity B 50b and cavity C 50c in one embodiment, cavity B 50b in other embodiments). Insert 51 includes a first insert (insert A 51a in one embodiment, insert C 51c in other embodiments) disposed inside the first cavity (cavity A 50a in one embodiment, cavity C 50c in other embodiments) and a second insert (insert 51b, 51c in one embodiment, insert 51b in other embodiments) disposed inside the second cavity (cavities 50b, 50c in one embodiment, cavity B 50b in other embodiments).A turbine stator blade 24 according to at least one embodiment of the present disclosure includes a closing plate (closing plate 71 in one embodiment, closing plate 171 in other embodiments) that closes the opening at one end of the first cavity (cavity A 50a in one embodiment, cavity C 50c in other embodiments) on one side (inner radial Dr in one embodiment, outer radial Dr in other embodiments) and a closing plate (closing plate 71 in one embodiment, closing plate 171 in other embodiments) from one side (in one embodiment) The device comprises a lid member (lid member 73 in one embodiment, lid member 173 in other embodiments) positioned at a distance from the radially inner (inside in the radial direction Dr in other embodiments) and at a distance from the opening (opening 50io of end 50i in one embodiment, opening 150io of end 150i in other embodiments) at one end of the second cavity (the B cavity 50b and C cavity 50c in one embodiment, the B cavity 50b in other embodiments) (the opening 50io of end 50i in one embodiment, the opening 150io of end 150i in other embodiments). The second cavity (the B cavity 50b and C cavity 50c in one embodiment, and the B cavity 50b in other embodiments), and the internal passage (the internal passage 44 in one embodiment, and the internal passage 144 in other embodiments) are in communication with the space (space 75 in one embodiment, and the rear edge space 175T in other embodiments) defined by the closing plate (the closing plate 71 in one embodiment, and the closing plate 171 in other embodiments) and the lid member (the lid member 73 in one embodiment, and the lid member 173 in other embodiments).

[0100] According to the configuration of (1) above, the second cavity (the B cavity 50b and C cavity 50c in one embodiment, the B cavity 50b in another embodiment) and the internal passage (the internal passage 44 in one embodiment, the internal passage 144 in another embodiment) are in communication via a space defined by a closing plate (the closing plate 71 in one embodiment, the closing plate 171 in another embodiment) and a lid member (the lid member 73 in one embodiment, the lid member 173 in another embodiment) (space 75 in one embodiment, the trailing edge space 175T in another embodiment). As a result, the cooling air after cooling the airfoil portion 25 from the inner surface in the second cavity (the B cavity 50b and C cavity 50c in one embodiment, the B cavity 50b in another embodiment) can be guided to the internal passages 44 and 144. As a result, the cooling air after the airfoil portion 25 has been cooled from the inside in the second cavity (the B cavity 50b and C cavity 50c in one embodiment, and the B cavity 50b in another embodiment) can be used to cool the shroud (the inner shroud 40 in one embodiment, and the outer shroud 140 in another embodiment), thus enabling effective use of the cooling air in the turbine stator blade 24.

[0101] (2) In some embodiments, in the configuration of (1) above, the closing plate (closing plate 71 in one embodiment, closing plate 171 in other embodiments) and the lid member (lid member 73 in one embodiment, lid member 173 in other embodiments) may define a part of the flow path for guiding cooling air from the opening at the end of one side (inner radial Dr in one embodiment, outer radial Dr in other embodiments) of the second cavity (the B cavity 50b and C cavity 50c in one embodiment, the B cavity 50b in other embodiments) to the internal passage (the internal passage 44 in one embodiment, the internal passage 144 in other embodiments).

[0102] According to the configuration of (2) above, the shroud (inner shroud 40 in one embodiment, outer shroud 140 in other embodiments) can be cooled with the cooling air after the airfoil portion 25 has been cooled from the inner surface in the second cavity (the B cavity 50b and C cavity 50c in one embodiment, and the B cavity 50b in other embodiments), so that the cooling air can be effectively utilized in the turbine stator blade 24.

[0103] (3) In some embodiments, in the configuration of (1) or (2) above, the second insert (inserts 51b, 51c in one embodiment, insert 51b in other embodiments) may have an internal insert channel 56 formed inside the second insert (inserts 51b, 51c in one embodiment, insert 51b in other embodiments) that extends in the direction of the blade height h, and a plurality of protrusions 52 that project from the outer surface 56ws of the second insert (inserts 51b, 51c in one embodiment, insert 51b in other embodiments) toward the inner wall surface (inner surface 34a of the blade wall 34) that defines the second cavity (the B cavity 50b and C cavity 50c in one embodiment, the B cavity 50b in other embodiments). It is preferable that each of the multiple protrusions 52 has multiple cooling holes 55 formed therein that communicate with the insert internal flow path 56 and open so as to face the inner wall surface (inner surface 34a of the wing wall 34) of the second cavity (the B cavity 50b and C cavity 50c in one embodiment, and the B cavity 50b in other embodiments). It is preferable that a cavity internal flow path 53 is formed inside the second cavity (the B cavity 50b and C cavity 50c in one embodiment, and the B cavity 50b in other embodiments) which is defined by two adjacent protrusions 52 and the inner wall surface (inner surface 34a of the wing wall 34) of the second cavity (the B cavity 50b and C cavity 50c in one embodiment, and the B cavity 50b in other embodiments). The cavity channel 53 is preferably in communication with the space 75 defined by the closing plate (closing plate 71 in one embodiment, closing plate 171 in other embodiments) and the lid member (lid member 73 in one embodiment, lid member 173 in other embodiments).

[0104] According to the configuration of (3) above, when cooling air is supplied to the internal flow path 56 of the second insert (inserts 51b, 51c in one embodiment, insert 51b in other embodiments), the cooling air is blown out from the internal flow path 56 of the insert through a plurality of cooling holes 55 toward the inner wall surface (inner surface 34a of the wing wall 34) of the second cavity (the B cavity 50b and C cavity 50c in one embodiment, the B cavity 50b in other embodiments). As a result, the airfoil portion 25 is cooled from the inside of the second cavity (the B cavity 50b and C cavity 50c in one embodiment, the B cavity 50b in other embodiments) by the cooling air blown out from the plurality of cooling holes 55 toward the inner wall surface (inner surface 34a of the wing wall 34) of the second cavity (the B cavity 50b and C cavity 50c in one embodiment, the B cavity 50b in other embodiments). Subsequently, the cooling air blown out from the multiple cooling holes 55 toward the inner wall surface (inner surface 34a of the wing wall 34) of the second cavity (the B cavity 50b and C cavity 50c in one embodiment, and the B cavity 50b in other embodiments) flows through the cavity internal passage 53 and into the space (space 75 in one embodiment, and trailing edge space 175T in other embodiments) defined by the closing plate (closing plate 71 in one embodiment, and closing plate 171 in other embodiments) and the lid member (lid member 73 in one embodiment, and lid member 173 in other embodiments). The cooling air that flows through the cavity channel 53 and into the space defined by the closing plate (closing plate 71 in one embodiment, closing plate 171 in other embodiments) and the lid member (lid member 73 in one embodiment, lid member 173 in other embodiments) (space 75 in one embodiment, rear edge space 175T in other embodiments) flows into the internal passage (internal passage 44 in one embodiment, internal passage 144 in other embodiments).Therefore, according to the configuration of (3) above, the shroud (inner shroud 40 in one embodiment, outer shroud 140 in other embodiments) can be cooled with the cooling air after the airfoil portion 25 has been cooled from the inner surface in the second cavity (the B cavity 50b and C cavity 50c in one embodiment, and the B cavity 50b in other embodiments), so that the cooling air can be effectively utilized in the turbine stator blade 24.

[0105] (4) In some embodiments, in any of the configurations (1) to (3) above, the first insert (insert 51a) and the second inserts (inserts 51b, 51c) may have a bottomed shape with an open end on the other side (outer radially Dr) in the wing height direction h. The bottom portion 59 on one side (inner radially Dr) of the second insert (inserts 51b, 51c) may be located one side (inner radially Dr) further to the side (inner radially Dr) than the bottom portion 59 on one side (inner radially Dr) of the first insert (insert 51a).

[0106] According to the configuration of (4) above, the cooling holes 55 provided in the protruding portions 52 of the second inserts (inserts 51b, 51c) can be positioned as far as possible on one side (inward in the radial direction Dr) in the wing height direction h, making it easier to cool one side (inward in the radial direction Dr) of the airfoil portion 25.

[0107] (5) In some embodiments, in any of the configurations (1) to (4) above, the cavity 50 may include a third cavity (C cavity 50c) which is different from the first cavity (A cavity 50a) and the second cavity (B cavity 50b), in which the third insert (C insert 51c) is located. The insert 51 may include the third insert (C insert 51c). The airfoil section 25 preferably has a first bulkhead (bulb 57 separating the A cavity 50a and the B cavity 50b) that separates the first cavity (A cavity 50a) and the second cavity (B cavity 50b) and extends in the airfoil height direction h, and a second bulkhead (bulb 57 separating the B cavity 50b and the C cavity 50c) that separates the second cavity (B cavity 50b) and the third cavity (C insert 51c). The end portion 57i on one side (radially inward Dr) of the first bulkhead (bulkhead 57 separating the A cavity 50a and the B cavity 50b) and the end portion 57i on one side (radially inward Dr) of the second bulkhead (bulkhead 57 separating the B cavity 50b and the C cavity 50c) should be at different positions in the wing height direction h.

[0108] According to the configuration of (5) above, the position of the wing height direction h may be different between the end 57i on one side (radially inward Dr) of the first bulkhead (bulkhead 57 separating the A cavity 50a and the B cavity 50b) and the end 57i on one side (radially inward Dr) of the second bulkhead (bulkhead 57 separating the B cavity 50b and the C cavity 50c).

[0109] (6) In some embodiments, in any of the configurations (1) to (5) above, the cavity 50 may include a first cavity 50a, a second cavity 50b, and a third cavity 50c formed in the airfoil portion 25 in order from the leading edge 43 side of the airfoil portion 25. One or two of the first cavity 50a, the second cavity 50b, and the third cavity 50c may be first cavities and the others may be second cavities.

[0110] According to the configuration of (6) above, the opening 50io at one end 50i on one side (radially inward Dr) of any one or two of the A cavity 50a, B cavity 50b, and C cavity 50c is closed by the closing plate 71. The space 75 defined by the closing plate 71 and the lid member 73 is in communication with the second cavity (not the first cavity) among the A cavity 50a, B cavity 50b, and C cavity 50c, and the internal passage 44 (leading edge side internal passage 44L). Therefore, since the second cavity and the internal passage 44 are in communication via the space 75 defined by the closing plate 71 and the lid member 73, the cooling air after cooling the airfoil portion 25 from the inner surface in the second cavity can be guided to the internal passage 44. As a result, the shroud (inner shroud 40) can be cooled with the cooling air after the airfoil section 25 has been cooled from the inside in the second cavity, so the cooling air can be effectively utilized in the turbine stator blade 24.

[0111] (7) In some embodiments, in any of the configurations (1) to (6) above, the second cavity may include a leading edge second cavity (B cavity 50b) and a trailing edge second cavity (C cavity 50c) located on the trailing edge 49 side of the airfoil portion 25 than the leading edge second cavity (B cavity 50b). The space 75 defined by the closing plate 71 and the lid member 73 may include a partition member (a partition wall 57 separating the B cavity 50b and the C cavity 50c) that separates the space 75 through which the leading edge second cavity (B cavity 50b) communicates (leading edge space 75L) from the space 75 through which the trailing edge second cavity (C cavity 50c) communicates (trailing edge space 75T).

[0112] According to the configuration of (7) above, the space 75 defined by the closing plate 71 and the lid member 73 may be divided into a space 75 (front edge space 75L) through which the front edge second cavity (B cavity 50b) communicates and a space 75 (rear edge space 75T) through which the rear edge second cavity (C cavity 50c) communicates.

[0113] (8) In some embodiments, in any of the configurations (1) to (7) above, the closing plate 71 may have a first fitting projection 83 that protrudes to the other side (outside in the radial direction Dr) in the wing height direction h and fits into a recess 81 formed at the end (bottom 59) of one side (inside in the radial direction Dr) of the first insert (insert 51a). The lid member 73 may have a second fitting projection 84 that protrudes to the other side (outside in the radial direction Dr) in the wing height direction h and fits into a recess 81 formed at the end (bottom 59) of one side (inside in the radial direction Dr) of the second insert (insert 51b, 51c).

[0114] According to the configuration of (8) above, the cooling holes 55 provided in the protruding portion 52 of the first insert (insert 51a) can be positioned on one side in the wing height direction h (inside the radial direction Dr), making it easier to cool one side of the airfoil portion 25. Similarly, according to the configuration of (8) above, the cooling holes 55 provided in the protruding portion 52 of the second insert (inserts 51b, 51c) can be positioned on one side in the wing height direction h (inside the radial direction Dr), making it easier to cool one side of the airfoil portion 25.

[0115] (9) In some embodiments, in any of the configurations (1) to (8) above, the second cavity may include a leading-edge second cavity (B cavity 50b) and a trailing-edge second cavity (C cavity 50c) which is formed on the trailing edge 49 side of the airfoil portion 25 and is adjacent to the leading-edge second cavity (B cavity 50b). The lid member 73 may include a leading edge lid member 73L positioned at a location one side (radially inward in the direction of Dr) away from the opening 50io at one end 50i of the leading edge second cavity (B cavity 50b), and a trailing edge lid member 73T, different from the leading edge lid member 73L, positioned at a location one side (radially inward in the direction of Dr) away from the opening 50io at one end 50i of the trailing edge second cavity (C cavity 50c). The airfoil portion 25 may have a partition wall 57 separating the leading edge second cavity (B cavity 50b) and the trailing edge second cavity (C cavity 50c). The leading edge lid member 73L and the trailing edge lid member 73T may be connected to the partition wall 57.

[0116] According to the configuration described in (9) above, the connection of the leading edge cover member 73L and the trailing edge cover member 73T to the airfoil portion 25 becomes relatively easy.

[0117] (10) In some embodiments, in any of the configurations (1) to (9) above, the shroud may be an inner shroud 40 connected to the inner end (hub side edge 24a) in the airfoil portion 25 in the airfoil height direction h.

[0118] According to the configuration of (10) above, the inner shroud 40 can be cooled with the cooling air after the airfoil section 25 has been cooled from the inner surface in the second cavity (cavities 50b, 50c), so that the cooling air can be effectively utilized in the turbine stator blade 24.

[0119] (11) In some embodiments, in any of the configurations (1) to (10) above, the lid member 73 may have a contact projection 91 that protrudes to the other side (outward in the radial direction Dr) in the wing height direction h and abuts against the inner wall surface of the second cavity (cavities 50b, 50c) (the inner surface 34a of the wing wall 34 and the side surface 57s of the partition wall 57).

[0120] According to the configuration of (11) above, by bringing the abutment projection 91 into contact with the inner wall surface (inner surface 34a of the wing wall 34 and the side surface 57s of the partition wall 57) that defines the second cavity (cavities 50b, 50c), it becomes easier to position the lid member 73 relative to the wing-shaped portion 25 when connecting the lid member 73 to the wing-shaped portion 25.

[0121] (12) In some embodiments, in the configuration of (11) above, the abutment projection 91 has an outer peripheral surface 92 that has an arc shape when viewed from the wing height direction h, and the outer peripheral surface 92 may abut against the inner wall surface of the second cavity (cavities 50b, 50c) (the inner surface 34a of the wing wall 34 and the side surface 57s of the partition wall 57).

[0122] According to the configuration described in (12) above, it becomes easier to ensure the positioning accuracy of the cover member 73 relative to the airfoil portion 25.

[0123] (13) In some embodiments, in the configuration of (12) above, the abutment projection 91 may abut the inner wall surface of the second cavity (cavities 50b, 50c) (inner surface 34a of the wing wall 34 and side surface 57s of the partition wall 57) at two different points (positions P1, P2) on the outer peripheral surface 92 when viewed from the wing height direction h. When viewed from the wing height direction h, the abutment projection 91 may have a notch 94 in which a part of the region further from the inner wall surface of the second cavity (cavities 50b, 50c) (inner surface 34a of the wing wall 34 and side surface 57s of the partition wall 57) is cut out of the two regions separated by the line segment L connecting the two points (positions P1, P2) on the outer peripheral surface 92.

[0124] According to the configuration of (13) above, by bringing the abutment projection 91 into contact with the inner wall surface of the second cavity (cavities 50b, 50c) (inner surface 34a of the wing wall 34 and side surface 57s of the partition wall 57) at the two points (positions P1, P2), it becomes easier to position the lid member 73 relative to the airfoil portion 25, thereby improving the positioning accuracy of the lid member 73 relative to the airfoil portion 25. Furthermore, according to the configuration of (13) above, by providing the notch 94, the volume of the abutment projection 91 that protrudes from the opening 50io of the end 50i on one side (inner radially Dr) of the second cavity (cavities 50b, 50c) to the space 75 defined by the closing plate 71 and the lid member 73 can be reduced. This reduces the increase in pressure loss due to the contact protrusion 91 of the cooling air flowing from the opening 50io at the end 50i on one side (inward radially Dr) of the second cavity (cavities 50b, 50c) into the space 75 defined by the closing plate 71 and the lid member 73.

[0125] (14) In some embodiments, in the configuration of (13) above, the second insert (inserts 51b, 51c) may have an internal insert channel 56 formed inside the second insert (inserts 51b, 51c) that extends in the direction of the blade height h, and a plurality of protrusions 52 that project from the outer surface 56ws of the second insert (inserts 51b, 51c) toward the inner wall surface (inner surface 34a of the blade wall 34) defining the second cavity (cavity 50b, 50c) in a cross section perpendicular to the direction of extension of the internal insert channel 56. Each of the plurality of protrusions 52 may have a plurality of cooling holes 55 formed therein that communicate with the internal insert channel 56 and open so as to face the inner wall surface (inner surface 34a of the blade wall 34) of the second cavity (cavity 50b, 50c). When viewed from the wing height direction h, it is desirable that the region between two adjacent protrusions 52 (cavity flow path 53) and at least a part of the notch 94 overlap.

[0126] According to the configuration described in (14) above, compared to the case where the notch 94 is not provided, the contact protrusion 91 is less likely to obstruct the flow of cooling air into the space 75 defined by the closing plate 71 and the lid member 73.

[0127] (15) In some embodiments, in any of the configurations (1) to (3), (5), or (6) above, the shroud may be an outer shroud (outer shroud 140 in other embodiments) connected to the outer end of the airfoil portion 25 in the airfoil height direction h.

[0128] According to the configuration of (15) above, the cooling air after the airfoil portion 25 has been cooled from the inside in the second cavity (cavity 50b) can be used to cool the outer shroud (outer shroud 140 in other embodiments), so that the cooling air can be effectively utilized in the turbine stator blade 24.

[0129] (16) A gas turbine 1 according to at least one embodiment of the present disclosure comprises a compressor 2 for compressing air, a combustor 4 for burning a mixture of air and fuel compressed by the compressor 2 to produce combustion gas, and a turbine 6 having a plurality of turbine stator blades 24 having any of the configurations of (1) to (15) above, and generating rotational driving force from the combustion gas.

[0130] According to the configuration described in (16) above, the cooling air can be effectively utilized in the turbine stator blades 24, thereby improving the efficiency of the gas turbine 1.

[0131] 1 Gas turbine 6 Turbine 24 Turbine stator blades 40 Inner shroud 50 Cavity 51 Insert 57 Middle wall (partition) 71 Closing plate 73 Cover member 83 First fitting projection 84 Second fitting projection 91 Contact projection 140 Outer shroud 171 Closing plate 173 Cover member

Claims

1. A turbine stator blade comprising: an airfoil; a shroud connected to one end of the airfoil in the height direction of the airfoil and having an internal passage at its periphery; and a cylindrical insert disposed inside a cavity extending in the height direction of the airfoil in the airfoil, wherein the cavity comprises a first cavity and a second cavity different from the first cavity; the insert comprises a first insert disposed inside the first cavity and a second insert disposed inside the second cavity; a closing plate defining at least a portion of the one end of the first cavity; and a cover member disposed at a position away from the closing plate to the one side and at a position away from the opening of the one end of the second cavity to the one side; wherein the second cavity and the internal passage communicate with a space defined by the closing plate and the cover member.

2. The turbine stator blade according to claim 1, wherein the closing plate and the lid member define a portion of a flow path for guiding cooling air from the opening at one end of the second cavity into the internal passage.

3. The turbine stator blade according to claim 1 or 2, wherein the second insert has an insert internal flow path formed inside the second insert and extending in the direction of the blade height, and a plurality of protrusions projecting from the outer surface of the second insert toward an inner wall surface defining the second cavity in a cross section perpendicular to the direction of extension of the insert internal flow path, each of the plurality of protrusions having a plurality of cooling holes that communicate with the insert internal flow path and open to face the inner wall surface of the second cavity, and a cavity internal flow path is formed inside the second cavity, defined by two adjacent protrusions among the plurality of protrusions and the inner wall surface of the second cavity, and the cavity internal flow path communicates with the space defined by the closing plate and the lid member.

4. The turbine stator blade according to claim 1 or 2, wherein the first insert and the second insert have a bottomed shape with an open end on the other side in the blade height direction, and the bottom on one side of the second insert is located on the one side further than the bottom on one side of the first insert.

5. The turbine stator blade according to claim 1 or 2, wherein the cavity includes a third cavity different from the first cavity and the second cavity, wherein the insert includes the third insert, and the airfoil portion has a first partition wall separating the first cavity and the second cavity and extending in the direction of the blade height, and a second partition wall separating the second cavity and the third cavity and extending in the direction of the blade height, wherein the one end of the first partition wall and the one end of the second partition wall are at different positions in the direction of the blade height.

6. The turbine stator vane according to claim 1 or 2, wherein the cavity includes an A cavity, a B cavity, and a C cavity formed in order from the leading edge side of the airfoil, and one or two of the A cavity, the B cavity, and the C cavity are the first cavity and the other is the second cavity.

7. The turbine stator vane according to claim 1 or 2, wherein the second cavity includes a leading-edge second cavity and a trailing-edge second cavity located on the trailing-edge side of the airfoil portion than the leading-edge second cavity, and further comprises a partition member that separates the space defined by the closing plate and the lid member from the space through which the leading-edge second cavity communicates with the space through which the trailing-edge second cavity communicates.

8. The turbine stator blade according to claim 1 or 2, wherein the closing plate has a first fitting projection that protrudes to the other side in the blade height direction and fits into a recess formed at the one end of the first insert, and the cover member has a second fitting projection that protrudes to the other side in the blade height direction and fits into a recess formed at the one end of the second insert.

9. The turbine stator vane according to claim 1 or 2, wherein the second cavity includes a leading edge second cavity and a trailing edge second cavity formed on the trailing edge side of the airfoil portion and adjacent to the leading edge second cavity, and the cover member includes a leading edge cover member positioned away from the opening at one end of the leading edge second cavity to the one side, and a trailing edge cover member different from the leading edge cover member, positioned away from the opening at one end of the trailing edge second cavity to the one side, and the airfoil portion has a partition wall separating the leading edge second cavity and the trailing edge second cavity, and the leading edge cover member and the trailing edge cover member are connected to the partition wall.

10. The turbine stator blade according to claim 1 or 2, wherein the shroud is an inner shroud connected to the inner end of the airfoil portion in the height direction of the blade.

11. The turbine stator blade according to claim 1 or 2, wherein the cover member has a contact projection that protrudes to the other side in the blade height direction and abuts against the inner wall surface defining the second cavity.

12. The turbine stator blade according to claim 11, wherein the abutment projection has an outer circumferential surface having an arc shape when viewed from the blade height direction, and the outer circumferential surface abuts the inner wall surface of the second cavity.

13. The turbine stator blade according to claim 12, wherein the abutment projection abuts the inner wall surface of the second cavity at two different points on the outer peripheral surface when viewed from the blade height direction, and has a notch portion in which a part of the region further from the inner wall surface of the second cavity is cut out, of two regions separated by a line segment connecting the two points on the outer peripheral surface when viewed from the blade height direction.

14. The turbine stator blade according to claim 13, wherein the second insert has an internal flow path formed inside the second insert and extending in the direction of the blade height, and a plurality of protrusions projecting from the outer surface of the second insert toward the inner wall surface defining the second cavity in a cross section perpendicular to the direction of extension of the internal flow path, and each of the plurality of protrusions has a plurality of cooling holes that communicate with the internal flow path and open toward the inner wall surface of the second cavity, and when viewed from the direction of the blade height, the region sandwiched between two adjacent protrusions of the plurality of protrusions overlaps with at least a part of the notch.

15. The turbine stator blade according to claim 1 or 2, wherein the shroud is an outer shroud connected to the outer end of the airfoil portion in the airfoil height direction.

16. A gas turbine comprising: a compressor for compressing air; a combustor for burning a mixture of air and fuel compressed by the compressor to produce combustion gas; and a turbine having a plurality of turbine stator blades as described in claim 1 or 2, for generating rotational driving force from the combustion gas.

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