Blade segment and gas turbine

Abstract

A blade segment according to at least one embodiment of the present disclosure comprises a first segment and a second segment that are bolted. At a first side portion of a first outer shroud of the first segment, a region on the leading edge side of a first airfoil portion is provided with at least one first cooling hole through which cooling air can flow and which opens toward a space sandwiched between the first outer shroud and a first inner shroud. At a second side portion of a second outer shroud of the second segment, a region on the leading edge side of a second airfoil portion is provided with at least one second cooling hole through which cooling air can flow and which opens toward a space sandwiched between the second outer shroud and a second inner shroud.

Description

Blade segment and gas turbine

[0001] This application claims priority to Japanese Patent Application No. 2023-202521, filed on November 30, 2023, with the Japan Patent Office, the contents of which are incorporated herein by reference.

[0002] For example, in a gas turbine as an example of a rotary machine, a stator vane segment is known as a turbine stator vane, in which two stator vanes (segments) each having one airfoil portion, one outer shroud, and one inner shroud are connected together (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2022-183695

[0004] In such a vane segment, the outer shrouds of two circumferentially adjacent vanes abut against each other at their circumferential side surfaces. In the leading edge region of the circumferential side surfaces, the temperature of the combustion gas passing through the gas path surface of the outer shroud is higher than that in the trailing edge region, so cooling by the cooling passages provided in the outer shroud tends to be insufficient, and thinning of the shroud is likely to occur.

[0005] In view of the above circumstances, at least one embodiment of the present disclosure has an object to reduce thinning of an outer shroud of a blade segment including two circumferentially adjacent stator blades.

[0006] (1) A blade segment according to at least one embodiment of the present disclosure comprises: a first segment including one first airfoil, a first outer shroud provided on the outer side of the one first airfoil in the airfoil height direction, and a first inner shroud provided on the inner side of the one first airfoil in the airfoil height direction; and a second segment including one second airfoil, a second outer shroud provided on the outer side of the one second airfoil in the airfoil height direction, and a second inner shroud provided on the inner side of the one second airfoil in the airfoil height direction, wherein the first outer shroud and the second outer shroud are bolted together, and the first inner shroud and the second inner shroud are bolted together, the first outer shroud has a first side portion formed with a first side surface facing the second outer shroud, and the second outer shroud has a second side portion formed with a second side surface facing the first outer shroud, A leading edge region of the first airfoil portion on the first side is provided with at least one first cooling hole that opens facing the space sandwiched between the first outer shroud and the first inner shroud and through which cooling air can flow, and a leading edge region of the second airfoil portion on the second side is provided with at least one second cooling hole that opens facing the space sandwiched between the second outer shroud and the second inner shroud and through which cooling air can flow.

[0007] (2) A gas turbine according to at least one embodiment of the present disclosure includes: a rotor; and a stator blade ring in which a plurality of blade segments having the configuration described in (1) above are arranged in the circumferential direction of the rotor.

[0008] According to at least one embodiment of the present disclosure, it is possible to reduce thickness loss of an outer shroud of a blade segment including two circumferentially adjacent stator vanes.

[0009] 1 is a schematic diagram showing the overall configuration of a gas turbine. It is a cross-sectional view showing a gas flow path of the turbine. It is a view of a turbine stator vane according to some embodiments, as seen from the radial outside. It is a view as viewed from the arrows IV-IV in FIG. 3. It is a schematic view of a first outer shroud and a second outer shroud of a blade segment according to a first embodiment, as seen from the inside to the outside in the blade height direction. It is a partial perspective view of a blade segment according to a second embodiment. It is a schematic view of a first side surface of a suction side first end portion of a first outer shroud of a blade segment according to a third embodiment, as seen from the circumferential direction. It is a schematic view of a first side surface of a pressure side second end portion of a second outer shroud of a blade segment according to the third embodiment, as seen from the circumferential direction. It is a schematic cross-sectional view of a cross section as viewed from the arrows IX-IX in FIG. 7. It is a view for explaining cooling air supply to first cooling holes and second cooling holes ...

[0010] Several embodiments of the present disclosure will be described below with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are not intended to limit the scope of the present disclosure and are merely illustrative examples. For example, expressions expressing relative or absolute arrangements, such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial," not only strictly express such arrangements, but also express relative displacements with a tolerance or angle or distance to the extent that the same function is achieved. For example, expressions expressing the equality of things, such as "same," "equal," and "homogeneous," not only express strict equality, but also express tolerance or differences to the extent that the same function is achieved. For example, expressions expressing shapes such as a square or cylindrical shape not only express shapes such as a square or cylindrical shape in the strict geometric sense, but also express shapes including concave and convex portions, chamfered portions, etc., to the extent that the same effect is achieved. On the other hand, the expressions "comprise," "include," "have," "includes," or "have" of one element are not exclusive expressions that exclude the presence of other elements.

[0011] FIG. 1 is a schematic diagram showing the overall configuration of a gas turbine, and FIG. 2 is a cross-sectional view showing a gas flow path of the turbine.

[0012] 1 , a gas turbine 10 includes a compressor 11, a combustor 12, and a turbine 13 coaxially arranged by a rotor 14, and a generator 15 is connected to one end of the rotor 14. In the following description, the direction in which the axis Ax of the rotor 14 extends is referred to as the axial direction Da, the circumferential direction about the axis Ax of the rotor 14 is referred to as the circumferential direction Dc, and the direction perpendicular to the axis Ax of the rotor 14 is referred to as the radial direction Dr. The radial direction Dr is also referred to as the blade height direction.

[0013] The compressor 11 generates high-temperature, high-pressure compressed air AC by compressing air AI taken in through an air intake as it passes through a plurality of stator vanes and rotor blades. The combustor 12 supplies a predetermined fuel FL to the compressed air AC and burns it to generate high-temperature, high-pressure combustion gas FG. The turbine 13 drives and rotates a rotor 14 as the high-temperature, high-pressure combustion gas FG generated in the combustor 12 passes through a plurality of stator vanes and rotor blades, and drives a generator 15 connected to the rotor 14.

[0014] 2 , in the turbine 13, the turbine stator vane (stator vane) 21 is configured such that the hub side of the airfoil portion 23 is fixed to the inner shroud 25 and the tip side is fixed to the outer shroud 27. The turbine rotor blade (rotor blade) 41 is configured such that the base end of the airfoil portion 43 is fixed to a platform 45. The outer shroud 27 and a ring segment 51 arranged on the tip side of the rotor blade 41 are supported on a casing (turbine casing) 30 via a heat shield ring 53, and the inner shroud 25 is supported on a support ring 31. Therefore, a combustion gas flow path 32 through which the combustion gas FG passes is formed along the axial direction Da as a space surrounded by the inner shroud 25, the outer shroud 27, the platform 45, and the ring segment 51.

[0015] Figure 3 is a view of a turbine stator vane 21 according to some embodiments, as seen from the outside in the radial direction Dr. Figure 4 is a view as seen from the arrow IV-IV in Figure 3. The turbine stator vane 21 according to some embodiments is configured as one blade segment 100, in which two segments 101, each having one airfoil portion 23 arranged relative to one outer shroud 27 and one inner shroud 25, are connected by bolts. Note that the turbine 13 according to this embodiment includes a stator vane ring 20 in which a plurality of blade segments 100 are arranged in the circumferential direction Dc of the rotor 14. Details of the blade segment 100 according to one embodiment will be described in detail later.

[0016] As shown in FIG. 3, the airfoil portion 23 is formed from a pressure-side blade surface 23c formed by a concave surface which is a pressure surface, and a suction-side blade surface 23d formed by a convex surface which is a negative pressure surface, and the pressure-side blade surface 23c and the suction-side blade surface 23d are connected at a leading edge 23a on the upstream side in the axial direction and a trailing edge 23b on the downstream side, thereby forming an integrated airfoil portion 23.

[0017] The inner shroud 25 and the outer shroud 27 function as gas path surface forming members. A gas path surface forming member defines the combustion gas flow path 32 and has a gas path surface with which the combustion gas FG comes into contact. When there is no need to particularly distinguish between the inner shroud 25 and the outer shroud 27, the inner shroud 25 and the outer shroud 27 may be simply referred to as the shroud 2.

[0018] (Regarding the Wing Segment 100) As described above, the wing segment 100 according to some embodiments includes two bolted segments 101. For convenience of explanation in the following description, the segment 101 arranged so that its suction side surface 23d faces the pressure side surface 23c of the other segment 101 will be referred to as the first segment 101A, and the segment 101 arranged so that its pressure side surface 23c faces the suction side surface 23d of the other segment 101 will be referred to as the second segment 101B. In Figure 3, the segment 101 on the right side of the figure is the first segment 101A, and the segment on the left side of the figure is the second segment 101B.

[0019] The first segment 101A includes one first airfoil 23A, a first outer shroud 27A provided on the outer side in the blade height direction of the one first airfoil 23A, and a first inner shroud 25A provided on the inner side in the blade height direction of the one first airfoil 23A. Similarly, the second segment 101B includes one second airfoil 23B, a second outer shroud 27B provided on the outer side in the blade height direction of the one second airfoil 23B, and a second inner shroud 25B (see FIG. 8 described later) provided on the inner side in the blade height direction of the one second airfoil 23B.

[0020] In the first segment 101A of the blade segment 100 according to some embodiments, the first outer shroud 27A includes an outer region 155, which is a space capable of storing cooling air supplied from the outside, on the radially outer side of the first outer shroud 27A, which is a surface opposite to the first gas path surface 27a1, which is the gas path surface of the first outer shroud 27A. The outer region 155 of the first segment 101A is a region surrounded by the peripheral edge of the first outer shroud 27A, i.e., the first end portion 151A (pressure-side first end portion 151Ap) on the pressure-side blade surface 23c side and the first end portion 151A (suction-side first end portion 151As) on the suction-side blade surface 23d side, which form both ends of the first outer shroud 27A in the circumferential direction Dc, and the first leading end portion 153A on the leading edge 23a side in the axial direction Da and the first trailing end portion 154A on the trailing edge 23b side, and forms a space portion 157 recessed inward in the radial direction Dr. An outer region bottom surface 155 a that forms the bottom surface of the outer region 155 of the first outer shroud 27A forms a radially outer surface on the opposite side of the first gas path surface 27 a 1 in the radial direction Dr. In the gas turbine 10 according to some embodiments, cooling air CA is supplied to the space portion 157 of the first segment 101A from the outside.

[0021] In the first segment 101A of the blade segment 100 according to some embodiments, the first inner shroud 25A has a first side end 158A on the suction side blade surface 23d side that forms the end of the first inner shroud 25A in the circumferential direction Dc.

[0022] Similarly, in the second segment 101B of the blade segment 100 according to some embodiments, the second outer shroud 27B has an outer region 155, which is a space capable of storing cooling air supplied from the outside, on the radially outer side Dr, which is the surface opposite to the second gas path surface 27a2, which is the gas path surface of the second outer shroud 27B. The outer region 155 of the second segment 101B is a region surrounded by the peripheral portion of the second outer shroud 27B, i.e., the second end portion 151B (pressure-side second end portion 151Bp) on the pressure-side blade surface 23c side and the second end portion 151B (suction-side second end portion 151Bs) on the suction-side blade surface 23d side, which form both ends of the second outer shroud 27B in the circumferential direction Dc, and the second leading end portion 153B on the leading edge 23a side and the second trailing end portion 154B on the trailing edge 23b side in the axial direction Da, and forms a space portion 157 recessed inward in the radial direction Dr. An outer region bottom surface 155a forming the bottom surface of the outer region 155 of the second outer shroud 27B forms a radially outer surface on the opposite side of the gas path surface 27a in the radial direction Dr. In the gas turbine 10 according to some embodiments, cooling air CA is supplied from outside to the space 157 of the second segment 101B.

[0023] In the second segment 101B of the blade segment 100 according to some embodiments, the second inner shroud 25B (see FIG. 8 described later) has a second side end portion 158B on the pressure-side blade surface 23c side that forms the end portion of the second inner shroud 25B in the circumferential direction Dc.

[0024] (Regarding the bolt connection between the first segment 101A and the second segment 101B) In the first segment 101A of the blade segment 100 according to some embodiments, a bolt hole 161 is formed penetrating the suction side first end portion 151As of the first outer shroud 27A and the first end portion 158A of the first inner shroud 25A on the suction side blade surface 23d side in the circumferential direction Dc. In the first segment 101A of the blade segment 100 according to some embodiments, a plurality of bolt holes 161 may be formed at intervals in the axial direction Da in the suction side first end portion 151As of the first outer shroud 27A. In the example shown in FIG. 3 and FIG. 4, there are two bolt holes 161, but there may be one, or three or more bolt holes 161. In the example shown in FIG. 4, one bolt hole 161 is formed in the first end portion 158A of the first inner shroud 25A, but a plurality of bolt holes 161 may be formed at intervals in the axial direction Da.

[0025] In the second segment 101B of the blade segment 100 according to one embodiment, a bolt hole 162 is formed penetrating the pressure-side second end portion 151Bp of the second outer shroud 27B and the second end portion 158B of the second inner shroud 25B on the pressure-side blade surface 23c side in the circumferential direction Dc. In the second segment 101B of the blade segment 100 according to one embodiment, a plurality of bolt holes 162 may be formed at intervals in the axial direction Da in the pressure-side second end portion 151Bp of the second outer shroud 27B. In the example shown in FIG. 3 , there are two bolt holes 162, but there may be one, or three or more bolt holes 162. In the example shown in FIG. 8 , one bolt hole 161 is formed in the second end portion 158B on the pressure-side blade surface 23c side of the second inner shroud 25B, but a plurality of bolt holes 161 may be formed at intervals in the axial direction Da.

[0026] The bolt holes 161 of the first segment 101A and the bolt holes 162 of the second segment 101B are positioned so that bolts 171 can be inserted through the bolt holes 161 and 162. In the blade segments 100 according to some embodiments, the first segment 101A and the second segment 101B are bolted together by inserting the bolts 171 into the bolt holes 161 and 162 and attaching nuts 172. In the turbine 13 of the gas turbine 10 according to some embodiments, a plurality of the above-described blade segments 100 are arranged in the circumferential direction Dc. Adjacent blade segments 100 in the circumferential direction Dc are not bolted together. A seal plate (not shown) is arranged between adjacent blade segments 100 in the circumferential direction Dc to prevent leakage of cooling air CA from between the adjacent blade segments 100 in the circumferential direction Dc.

[0027] (Cooling Structure of Outer Shroud 27) The cooling structure of the outer shroud 27 will be described below. In the outer region 155 of the first segment 101A and the second segment 101B, an impingement plate (not shown) having a plurality of through holes is arranged so as to cover the entire outer region bottom surface 155a. The impingement plate (not shown) covers the hatched region in FIG. 3. The outer region 155 forming the space portion 157 is divided by the impingement plate (not shown) into a space portion 157 on the outer side in the radial direction Dr and a space portion 157 on the inner side in the radial direction Dr. The space portion 157 on the outer side in the radial direction Dr and the space portion 157 on the inner side in the radial direction Dr are in communication with each other via the through holes in the impingement plate (not shown).

[0028] The cooling air supplied to the space 157 is supplied to the space 157 on the radially inner side in the radial direction Dr through through holes in an impingement plate (not shown), and performs impingement cooling (impingement cooling) on ​​the outer region bottom surface 155a. By impingement cooling the outer region bottom surface 155a, overheating of the first gas path surface 27a1 and the second gas path surface 27a2 due to the combustion gas FG is suppressed. The cooling air that has impingement cooled the outer region bottom surface 155a is supplied to a first circumferential passage 121, a second circumferential passage 122, a ventral side first side passage 131p, a suction side first side passage 131s, a ventral side second side passage 132p, and a suction side second side passage 132s, which will be described later.

[0029] In the first segment 101A according to some embodiments, a first opening 111 is formed in a surface of the first leading end portion 153A facing the trailing edge 23b, i.e., in a wall surface facing the space 157 on the inside in the radial direction Dr. In the first segment 101A according to some embodiments, a first circumferential passage 121 extending in the circumferential direction Dc is formed in the first leading end portion 153A. In the first segment 101A according to some embodiments, a ventral first side passage 131p extending in the axial direction Da is formed in the ventral first end portion 151Ap, and a suction first side passage 131s extending in the axial direction Da is formed in the suction first end portion 151As.

[0030] In the first segment 101A according to some embodiments, the first circumferential passage 121 is a passage that connects the first opening 111 with the ventral-side first side passage 131p and also connects the first opening 111 with the suction-side first side passage 131s. In the first segment 101A according to some embodiments, the ventral-side first side passage 131p is a passage that is formed in the ventral-side first side end portion 151Ap from the leading edge 23a to the trailing edge 23b, and has an upstream end connected to the first circumferential passage 121 and a downstream end that opens to the trailing-edge end 27d of the first outer shroud 27A. In the first segment 101A according to some embodiments, the suction side first side passage 131s is a passage formed at the suction side first side end portion 151As from the leading edge 23a side to the trailing edge 23b side, and has an upstream end connected to the first circumferential passage 121 and a downstream end opening to the trailing edge side end portion 27d of the first outer shroud 27A.

[0031] In the first segment 101A according to some embodiments, the cooling air that has impingement cooled the outer region bottom surface 155a flows from the first openings 111 into the first circumferential passages 121 in the first leading edge end portion 153A, and cools the first leading edge end portion 153A by flowing through the first circumferential passages 121. The cooling air that has flowed through the first circumferential passages 121 flows through the pressure side first side passages 131p and the suction side first side passages 131s to cool the pressure side first side end portion 151Ap and the suction side first side end portion 151As, and is then discharged to the outside of the first outer shroud 27A from the trailing edge side end portion 27d of the first outer shroud 27A.

[0032] In the second segment 101B according to some embodiments, a second opening 112 is formed in a surface of the second leading end portion 153B facing the trailing edge 23b, i.e., in a wall surface facing the space 157 on the inside in the radial direction Dr. In the second segment 101B according to some embodiments, a second circumferential passage 122 extending in the circumferential direction Dc is formed in the second leading end portion 153B. In the second segment 101B according to some embodiments, a ventral second side passage 132p extending in the axial direction Da is formed in the ventral second end portion 151Bp, and a suction side second side passage 132s extending in the axial direction Da is formed in the suction side second end portion 151Bs.

[0033] In the second segment 101B according to some embodiments, the second circumferential passage 122 is a passage that connects the second opening 112 with the suction-side second side passage 132s and also connects the second opening 112 with the ventral-side second side passage 132p. In the second segment 101B according to some embodiments, the ventral-side second side passage 132p is a passage formed in the ventral-side second side end portion 151Bp from the leading edge 23a to the trailing edge 23b, and has an upstream end connected to the second circumferential passage 122 and a downstream end that opens to the trailing-edge end 27d of the second outer shroud 27B. In the second segment 101B according to some embodiments, the suction side second side passage 132s is a passage formed at the suction side second side end portion 151Bs from the leading edge 23a side to the trailing edge 23b side, and has an upstream end connected to the second circumferential passage 122 and a downstream end opening to the trailing edge side end portion 27d of the second outer shroud 27B.

[0034] In the second segment 101B according to some embodiments, the cooling air that has impingement cooled the outer region bottom surface 155a flows from the second openings 112 into the second circumferential passages 122 in the second leading edge portion 153B, and cools the second leading edge portion 153B by flowing through the second circumferential passages 122. The cooling air that has flowed through the second circumferential passages 122 flows through the pressure side second side passages 132p and the suction side second side passages 132s to cool the pressure side second end portion 151Bp and the suction side second end portion 151Bs, and is then discharged to the outside of the second outer shroud 27B from the trailing edge side end portion 27d of the second outer shroud 27B.

[0035] (First cooling hole 181 and second cooling hole 182 for the first embodiment) FIG. 5 is a schematic diagram of the first outer shroud 27A and the second outer shroud 27B in the blade segment 100 according to the first embodiment, viewed from the inside to the outside in the blade height direction. In the blade segment 100 according to some embodiments, including the first embodiment and other embodiments described later, a first side surface 191 facing the second outer shroud 27B is formed at the suction side first end portion 151As of the first outer shroud 27A. In the blade segment 100 according to some embodiments, a second side surface 192 facing the first outer shroud 27A is formed at the pressure side second end portion 151Bp of the second outer shroud 27B. In the blade segment 100 according to some embodiments, a third side surface 193 is formed at the pressure side first end portion 151Ap of the first outer shroud 27A on the opposite side to the first side surface 191 across the first airfoil section 23A. In the blade segment 100 according to some embodiments, a fourth side surface 194 is formed on the suction side second side end portion 151Bs of the second outer shroud 27B, on the opposite side to the second side surface 192 across the second airfoil portion 23B.

[0036] In the blade segment 100 according to the first embodiment, a region R1 at the suction side first end 151As on the leading edge 23a side of the first airfoil section 23A is provided with at least one first cooling hole 181 through which cooling air can flow, the first cooling hole 181 opening toward a space sandwiched between the first outer shroud 27A and the first inner shroud 25A. In the example shown in FIG. 5 , a plurality of first cooling holes 181 are provided. In the blade segment 100 according to the first embodiment, a region R2 at the pressure side second end 151Bp on the leading edge 23a side of the second airfoil section 23B is provided with at least one second cooling hole 182 through which cooling air can flow, the second cooling hole 182 opening toward a space sandwiched between the second outer shroud 27B and the second inner shroud 25B. In the example shown in FIG. 5 , a plurality of second cooling holes 182 are provided.

[0037] In the blade segment 100 according to the first embodiment, a region R3 at the pressure-side first end 151Ap on the leading edge 23a side of the first airfoil section 23A is provided with at least one third cooling hole 183 through which cooling air can flow, the third cooling hole 183 opening toward a space sandwiched between the first outer shroud 27A and the first inner shroud 25A. In the example shown in FIG. 5, a plurality of third cooling holes 183 are provided. In the blade segment 100 according to the first embodiment, a region R4 at the suction-side second end 151Bs on the leading edge 23a side of the second airfoil section 23B is provided with at least one fourth cooling hole 184 through which cooling air can flow, the fourth cooling hole 184 opening toward a space sandwiched between the second outer shroud 27B and the second inner shroud 25B. In the example shown in FIG. 5, a plurality of fourth cooling holes 184 are provided.

[0038] As described below, the first cooling holes 181 may be supplied with cooling air from a first supply passage 241 that opens into a space 157 that is more inward in the radial direction Dr than an impingement plate (not shown). Furthermore, as described below, the first cooling holes 181 may be supplied with cooling air from a first circumferential passage 121. As described below, the third cooling holes 183 may be supplied with cooling air from a third supply passage 243 that opens into a space 157 that is more inward in the radial direction Dr than an impingement plate (not shown). Furthermore, as described below, the third cooling holes 183 may be supplied with cooling air from the first circumferential passage 121. This allows the cooling air from the space 157 that is more inward in the radial direction Dr than an impingement plate (not shown) to flow through the first cooling holes 181 or the third cooling holes 183 and be discharged from an opening that faces the space sandwiched between the first outer shroud 27A and the first inner shroud 25A.

[0039] As described below, the second cooling holes 182 may be supplied with cooling air from a second supply passage 242 that opens into a space 157 that is more inward in the radial direction Dr than an impingement plate (not shown). Furthermore, as described below, the second cooling holes 182 may be supplied with cooling air from the second circumferential passage 122. As described below, the fourth cooling holes 184 may be supplied with cooling air from a fourth supply passage 244 that opens into a space 157 that is more inward in the radial direction Dr than an impingement plate (not shown). Furthermore, as described below, the fourth cooling holes 184 may be supplied with cooling air from the second circumferential passage 122. This allows the cooling air from the space 157 that is more inward in the radial direction Dr than an impingement plate (not shown) to flow through the second cooling holes 182 or the fourth cooling holes 184 and be discharged from an opening that faces the space sandwiched between the first outer shroud 27A and the first inner shroud 25A.

[0040] In a blade segment 100 in which the first segment 101A and the second segment 101B are bolted together, the regions R1 and R2 on the leading edge 23a side of the suction side first end 151As and the pressure side second end 151Bp tend to have higher temperatures than the regions on the trailing edge 23b side, which makes it easier for metal loss to occur in the regions on the leading edge 23a side of the first side surface 191 and the second side surface 192. According to the blade segment 100 of the first embodiment, the first cooling holes 181 and the second cooling holes 182 are provided in the regions R1 and R2 on the leading edge 23a side of the suction side first end 151As and the pressure side second end 151Bp, thereby effectively cooling the regions R1 and R2 on the leading edge 23a side of the suction side first end 151As and the pressure side second end 151Bp. This reduces metal loss in the regions on the leading edge 23a side of the first side surface 191 and the second side surface 192.

[0041] In the gas turbine 10 according to this embodiment, the turbine 13 includes a stator blade ring 20 in which a plurality of blade segments 100 according to some embodiments are arranged in the circumferential direction Dc of the rotor 14. This reduces thinning of the blade segments 100 in the regions on the leading edge 23 a side of the first side surface 191 and the second side surface 192, thereby reducing the frequency of replacing the blade segments 100 and reducing the maintenance cost of the gas turbine 10.

[0042] (Regarding the Second Embodiment: First Chamfered Portion 221 and Second Chamfered Portion 222) Fig. 6 is a perspective view of the vicinity of the above-mentioned regions R1 and R2 in the blade segment 100 according to the second embodiment. In the blade segment 100 according to the second embodiment, the first outer shroud 27A has a first chamfered portion 221 obtained by chamfering a corner 201 (see Fig. 5) at which the first side surface 191, a leading-edge-side first side surface 211 facing the leading edge 23a of the first airfoil section 23A within the side surface of the first outer shroud 27A, and a first gas path surface 27a1 facing a space sandwiched between the first outer shroud 27A and the first inner shroud 25A intersect. In the blade segment 100 according to the second embodiment, the second outer shroud 27B has a second chamfered portion 222 formed by chamfering a corner 202 (see FIG. 5 ) at which the second side surface 192, a leading-edge-side second side surface 212 facing the leading edge 23 a of the second airfoil section 23B within the side surface of the second outer shroud 27B, and a second gas path surface 27 a2 facing the space sandwiched between the second outer shroud 27B and the second inner shroud 25B intersect.

[0043] In the blade segment 100 according to the second embodiment, the first chamfered portion 221 and the second chamfered portion 222 are provided with a thermal barrier coating, similar to the first gas path surface 27a1 and the second gas path surface 27a2.

[0044] The corners 201 of the first outer shroud 27A and the corners 202 of the second outer shroud 27B are difficult to cool and relatively prone to thinning. According to the blade segment 100 according to the second embodiment, the corners 201 and 202, which are relatively prone to thinning, are chamfered, so that thinning can be effectively suppressed.

[0045] In the blade segment 100 according to the second embodiment, when viewed from the blade height direction of the first airfoil section 23A, the intersection angle θ1 (see FIG. 5 ) between the first side surface 191 and the leading-edge-side first side surface 211 is an acute angle. At least one of the first cooling holes 181 may open to the first chamfered portion 221. When the intersection angle θ1 between the first side surface 191 and the leading-edge-side first side surface 211 is an acute angle, it is more difficult to form the cooling hole (first cooling hole 181) near the corner where the first side surface 191 and the leading-edge-side first side surface 211 intersect than when the intersection angle θ1 is an obtuse angle. In the blade segment 100 according to the second embodiment, it is easier to form the cooling hole (first cooling hole 181) in a chamfered portion such as the first chamfered portion 221, and therefore it is easier to form the first cooling hole 181. This allows the first cooling holes 181 to be provided in areas that are difficult to cool and where thinning is relatively likely to occur, thereby effectively suppressing thinning.

[0046] (Regarding the Third Embodiment: First Coating Region 231 and Second Coating Region 232) Fig. 7 is a schematic diagram of the first side surface 191 of the suction-side first end portion 151As of the first outer shroud 27A in the blade segment 100 according to the third embodiment, as viewed from the circumferential direction Dc. Fig. 8 is a schematic diagram of the first side surface 191 of the pressure-side second end portion 151Bp of the second outer shroud 27B in the blade segment 100 according to the third embodiment, as viewed from the circumferential direction Dc. Fig. 9 is a schematic cross-sectional view taken along the line IX-IX in Fig. 7 .

[0047] In the blade segment 100 according to the third embodiment, the first side surface 191 includes a first coating region 231 in which an oxidation-resistant coating is applied to at least a portion of a region of the first side surface 191 that is closer to the leading edge 23 a of the first airfoil section 23A. In the blade segment 100 according to the third embodiment, the second side surface 192 includes a second coating region 232 in which an oxidation-resistant coating is applied to at least a portion of a region of the second side surface 192 that is closer to the leading edge 23 a of the second airfoil section 23B. The first coating region 231 and the second coating region 232 face each other in the direction in which the first outer shroud and the second outer shroud are aligned, i.e., in the circumferential direction Dc. This reduces metal loss in the first coating region 231 and the second coating region 232.

[0048] The oxidation-resistant coating layer formed in the first coating region 231 and the second coating region 232 may be composed of CoNiCrAlY, NiCrAlY, CoCrAlY or MCrAlX (wherein M is Ni, Co or an alloy of Ni and Co, and X is Hf, Si or Ta).

[0049] In the blade segment 100 according to the third embodiment, the first side surface 191 preferably has no step at the boundary between the first coating region 231 and a region other than the first coating region 231. That is, when the first coating region 231 is formed on the first side surface 191, the region corresponding to the first coating region 231 may be shaped to be recessed in the circumferential direction Dc relative to the other regions. Similarly, the second side surface 192 preferably has no step at the boundary between the second coating region 232 and a region other than the second coating region 232. That is, when the second coating region 232 is formed on the second side surface 192, the region corresponding to the second coating region 232 may be shaped to be recessed in the circumferential direction Dc relative to the other regions. This prevents damage to the oxidation-resistant coatings formed on the first coating region 231 and the second coating region 232, and allows the first coating region 231 and the second coating region 232 to face each other without any gaps when the first segment 101A and the second segment 101B are joined by bolts.

[0050] In the blade segment 100 according to the third embodiment, the first coating region 231 is preferably formed in a region of the first side surface 191 from the end 191a on the leading edge 23a side of the first airfoil portion 23A to a position a specified distance a1 from the end 191a toward the trailing edge 23b of the first airfoil portion 23A, and also in a region of the first side surface 191 from the end 191b on the inner side in the blade height direction of the first airfoil portion 23A to a position a specified distance a2 from the end 191b toward the outer side in the blade height direction of the first airfoil portion 23A. As described above, the region where the first coating region 231 should be formed is a region of the first side surface 191 where metal loss is relatively likely to occur. According to the blade segment 100 according to the third embodiment, the first coating region 231 is formed in a region of the first side surface 191 where metal loss is relatively likely to occur, thereby effectively reducing metal loss in the first side surface 191.

[0051] In the blade segment 100 according to the third embodiment, the second coating region 232 is preferably formed in a region of the second side surface 192 from the end 192a on the leading edge 23a side of the second airfoil portion 23B to a position a specified distance a3 from the end 192a toward the trailing edge 23b of the second airfoil portion 23B, and also in a region of the second side surface 192 from the end 192b on the inner side in the blade height direction of the second airfoil portion 23B to a position a specified distance a4 from the end 192b toward the outer side in the blade height direction of the second airfoil portion 23B. As described above, the region where the second coating region 232 should be formed is a region of the second side surface 192 where metal loss is relatively likely to occur. According to the blade segment 100 according to the third embodiment, the second coating region 232 is formed in a region of the second side surface 192 where metal loss is relatively likely to occur, thereby effectively reducing metal loss in the second side surface 192.

[0052] (Regarding the Fourth Embodiment: Supply of Cooling Air to the First Cooling Holes 181 and the Second Cooling Holes 182) Fig. 10 is a diagram for explaining the supply of cooling air to the first cooling holes 181 and the second cooling holes 182 for the blade segment 100 according to the fourth embodiment, and is a schematic diagram of the outer shroud 27 viewed from the outside to the inside in the blade height direction. Fig. 11 is a diagram for explaining the supply of cooling air to the first cooling holes 181 and the second cooling holes 182 for the blade segment 100 according to the fourth embodiment, and is a schematic diagram of the outer shroud 27 viewed from the inside to the outside in the blade height direction. Note that Figs. 10 and 11 explain the first outer shroud 27A and the second outer shroud 27B, and the reference numeral for the second outer shroud 27B is given in parentheses.

[0053] (First supply passage 241) In the blade segment 100 according to the fourth embodiment, the first outer shroud 27A has a first supply passage 241 different from the first circumferential passage 121 and the suction side first side passage 131s, which is configured to be able to supply cooling air supplied from a space portion 157, which is a space on the opposite side of the first outer shroud from the space sandwiched between the first outer shroud 27A and the first inner shroud 25A, to the first cooling holes 181.

[0054] In the blade segment 100 according to the fourth embodiment, the first circumferential passage 121 and the suction side first side passage 131s are connected by a first suction side connecting passage 141s near the area where the first leading edge end portion 153A and the suction side first side end portion 151As of the first outer shroud 27A intersect. The first supply passage 241 is formed, for example, to pass outside the first suction side connecting passage 141s in the blade height direction, and is not connected to the first circumferential passage 121, the suction side first side passage 131s, and the first suction side connecting passage 141s. The first supply passage 241 and the first suction side connecting passage 141s may or may not overlap when viewed from the blade height direction.

[0055] An inlet opening 241a on the cooling air inlet side of the first supply passage 241 opens to a surface of the first leading end portion 153A of the first outer shroud 27A facing the trailing edge 23b, i.e., a wall surface facing the space portion 157 on the inside in the radial direction Dr. An opening on the cooling air outlet side of the first supply passage 241 is connected to a first suction-side cavity 251s formed in the vicinity of a region where the first leading end portion 153A and the suction-side first end portion 151As of the first outer shroud 27A intersect.

[0056] In the blade segment 100 according to the fourth embodiment, the multiple first cooling holes 181 are connected to the first suction side cavity 251s. That is, in the first segment 101A according to the fourth embodiment, the cooling air that has impingement cooled the outer region bottom surface 155a flows from the inlet opening 241a into the first supply passage 241 and is supplied to the first suction side cavity 251s. The cooling air supplied to the first suction side cavity 251s flows into each first cooling hole 181 and flows through each first cooling hole 181 to cool the above-mentioned region R1, and then is discharged from an opening facing the space sandwiched between the first outer shroud 27A and the first inner shroud 25A.

[0057] According to the blade segment 100 according to the fourth embodiment, by supplying cooling air from the first supply passage 241 to the first cooling holes 181, it is easy to ensure the flow rate of the cooling air supplied to the first cooling holes 181, and the region R1 on the leading edge 23 a side of the suction-side first lateral end portion 151As can be effectively cooled. This makes it possible to effectively reduce thinning of the region on the leading edge 23 a side of the first side surface 191.

[0058] (Second supply passage 242) In the blade segment 100 according to the fourth embodiment, the second outer shroud 27B has a second supply passage 242 different from the second circumferential passage 122 and the ventral side second side passage 132p, which is configured to be able to supply, to the second cooling holes 182, cooling air supplied from a space portion 157, which is a space on the opposite side of the second outer shroud 27B from the space sandwiched between the second outer shroud 27B and the second inner shroud 25B.

[0059] In the blade segment 100 according to the fourth embodiment, the second circumferential passage 122 and the pressure-side second side passage 132p are connected by a second pressure-side connecting passage 142p near the area where the second leading edge end 153B and the pressure-side second side end 151Bp of the second outer shroud 27B intersect. The second supply passage 242 is formed, for example, to pass outside the second pressure-side connecting passage 142p in the blade height direction, and is not connected to the second circumferential passage 122, the pressure-side second side passage 132p, and the second pressure-side connecting passage 142p. The second supply passage 242 and the second pressure-side connecting passage 142p may or may not overlap when viewed from the blade height direction.

[0060] An inlet opening 242a on the cooling air inlet side of the second supply passage 242 opens to a surface facing the trailing edge 23b of the second leading end portion 153B of the second outer shroud 27B, i.e., to a wall surface facing the space portion 157 on the inner side in the radial direction Dr. An opening on the cooling air outlet side of the second supply passage 242 is connected to a second ventral side cavity 252p formed in the vicinity of a region where the second leading end portion 153B and the ventral side second end portion 151Bp of the second outer shroud 27B intersect.

[0061] In the blade segment 100 according to the fourth embodiment, the multiple second cooling holes 182 are connected to the second plenum cavity 252p. That is, in the second segment 101B according to the fourth embodiment, the cooling air that has impingement cooled the outer region bottom surface 155a flows from the inlet opening 242a into the second supply passage 242 and is supplied to the second plenum cavity 252p. The cooling air supplied to the second plenum cavity 252p flows into each second cooling hole 182 and flows through each second cooling hole 182, thereby cooling the above-mentioned region R2, and is then discharged from an opening facing the space sandwiched between the second outer shroud 27B and the second inner shroud 25B.

[0062] According to the blade segment 100 according to the fourth embodiment, by supplying cooling air from the second supply passage 242 to the second cooling holes 182, it is easier to ensure the flow rate of the cooling air supplied to the second cooling holes 182, and the region R2 on the leading edge 23 a side of the pressure-side second lateral end portion 151Bp can be effectively cooled. This makes it possible to effectively reduce thinning of the region on the leading edge 23 a side of the second side surface 192.

[0063] (Third supply passage 243) In the blade segment 100 according to the fourth embodiment, the first outer shroud 27A has a third supply passage 243 that is different from the first circumferential passage 121 and the pressure-side first side passage 131p and is configured to be able to supply cooling air supplied from the space portion 157 to the third cooling hole 183.

[0064] In the blade segment 100 according to the fourth embodiment, the first circumferential passage 121 and the pressure-side first side passage 131p are connected by a first pressure-side connecting passage 141p near the area where the first leading edge end portion 153A and the pressure-side first side end portion 151Ap of the first outer shroud 27A intersect. The third supply passage 243 is formed, for example, to pass outside the first pressure-side connecting passage 141p in the blade height direction, and is not connected to the first circumferential passage 121, the pressure-side first side passage 131p, and the first pressure-side connecting passage 141p. The third supply passage 243 and the first pressure-side connecting passage 141p may or may not overlap when viewed from the blade height direction.

[0065] An inlet opening 243a on the cooling air inlet side of the third supply passage 243 opens to a surface facing the trailing edge 23b of the first leading end portion 153A of the first outer shroud 27A, i.e., to a wall surface facing the space portion 157 on the inside in the radial direction Dr. An opening on the cooling air outlet side of the third supply passage 243 is connected to a first ventral side cavity 251p formed in the vicinity of a region where the first leading end portion 153A and the ventral side first end portion 151Ap of the first outer shroud 27A intersect.

[0066] In the blade segment 100 according to the fourth embodiment, the multiple third cooling holes 183 are connected to the first plenum cavity 251p. That is, in the first segment 101A according to the fourth embodiment, the cooling air that has impingement cooled the outer region bottom surface 155a flows from the inlet opening 243a into the third supply passage 243 and is supplied to the first plenum cavity 251p. The cooling air supplied to the first plenum cavity 251p flows into each third cooling hole 183 and flows through each third cooling hole 183, thereby cooling the above-mentioned region R3, and is then discharged from an opening facing the space sandwiched between the first outer shroud 27A and the first inner shroud 25A.

[0067] (Fourth supply passage 244) In the blade segment 100 according to the fourth embodiment, the second outer shroud 27B has a fourth supply passage 244 that is different from the second circumferential passage 122 and the suction side second side passage 132s and is configured to be able to supply the cooling air supplied from the space portion 157 to the fourth cooling hole 184.

[0068] In the blade segment 100 according to the fourth embodiment, the second circumferential passage 122 and the suction side second side passage 132s are connected by the second suction side connecting passage 142s near the area where the second leading edge end portion 153B and the suction side second side end portion 151Bs of the second outer shroud 27B intersect. The fourth supply passage 244 is formed, for example, to pass outside the second suction side connecting passage 142s in the blade height direction, and is not connected to the second circumferential passage 122, the suction side second side passage 132s, and the second suction side connecting passage 142s. The fourth supply passage 244 and the second suction side connecting passage 142s may or may not overlap when viewed from the blade height direction.

[0069] An inlet opening 244a on the cooling air inlet side of the fourth supply passage 244 opens to a surface of the second leading end portion 153B of the second outer shroud 27B facing the trailing edge 23b, i.e., to a wall surface facing the space portion 157 on the inner side in the radial direction Dr. An opening on the cooling air outlet side of the fourth supply passage 244 is connected to a second suction-side cavity 252s formed in the vicinity of a region where the second leading end portion 153B and the suction-side second end portion 151Bs of the second outer shroud 27B intersect.

[0070] In the blade segment 100 according to the fourth embodiment, the multiple fourth cooling holes 184 are connected to the second suction side cavity 252s. That is, in the second segment 101B according to the fourth embodiment, the cooling air that has impingement cooled the outer region bottom surface 155a flows from the inlet opening 244a into the fourth supply passage 244 and is supplied to the second suction side cavity 252s. The cooling air supplied to the second suction side cavity 252s flows into each fourth cooling hole 184 and flows through each fourth cooling hole 184, thereby cooling the above-mentioned region R4, and is then discharged from an opening facing the space sandwiched between the second outer shroud 27B and the second inner shroud 25B.

[0071] (Regarding the Fifth Embodiment: Supply of Cooling Air to the First Cooling Holes 181 and the Second Cooling Holes 182) Fig. 12 is a diagram for explaining the supply of cooling air to the first cooling holes 181 and the second cooling holes 182 for the blade segment 100 according to the fifth embodiment, and is a schematic diagram of the outer shroud 27 viewed from the outside to the inside in the blade height direction. Fig. 13 is a diagram for explaining the supply of cooling air to the first cooling holes 181 and the second cooling holes 182 for the blade segment 100 according to the fifth embodiment, and is a schematic diagram of the outer shroud 27 viewed from the inside to the outside in the blade height direction. Note that Figs. 12 and 13 explain the first outer shroud 27A and the second outer shroud 27B, and the reference numeral for the second outer shroud 27B is given in parentheses.

[0072] In the blade segment 100 according to the fifth embodiment, at least some of the multiple first cooling holes 181 are connected to the first circumferential passage 121. This allows cooling air to be supplied to the first cooling holes 181 from the first circumferential passage 121. Furthermore, in the blade segment 100 according to the fifth embodiment, at least some of the multiple first cooling holes 181 are connected to the suction side first side passage 131s. This allows cooling air from the first circumferential passage 121 to be supplied to the first cooling holes 181 via the suction side first side passage 131s. Note that all of the multiple first cooling holes 181 may be connected to the first circumferential passage 121, or all of the multiple first cooling holes 181 may be connected to the suction side first side passage 131s.

[0073] In the blade segment 100 according to the fifth embodiment, at least some of the multiple second cooling holes 182 are connected to the second circumferential passage 122. This allows cooling air to be supplied to the second cooling holes 182 from the second circumferential passage 122. Furthermore, at least some of the multiple second cooling holes 182 are connected to the pressure-side second side passage 132p. This allows cooling air from the second circumferential passage 122 to be supplied to the second cooling holes 182 via the pressure-side second side passage 132p. Note that all of the multiple second cooling holes 182 may be connected to the second circumferential passage 122, or all of the multiple second cooling holes 182 may be connected to the pressure-side second side passage 132p.

[0074] In the blade segment 100 according to the fifth embodiment, at least some of the multiple third cooling holes 183 are connected to the first circumferential passage 121. This allows cooling air to be supplied to the third cooling holes 183 from the first circumferential passage 121. Furthermore, at least some of the multiple third cooling holes 183 are connected to the pressure-side first side passage 131p. This allows cooling air from the first circumferential passage 121 to be supplied to the third cooling holes 183 via the pressure-side first side passage 131p. Note that all of the multiple third cooling holes 183 may be connected to the first circumferential passage 121, or all of the multiple third cooling holes 183 may be connected to the pressure-side first side passage 131p.

[0075] In the blade segment 100 according to the fifth embodiment, at least some of the multiple fourth cooling holes 184 are connected to the second circumferential passage 122. This allows cooling air to be supplied to the fourth cooling holes 184 from the second circumferential passage 122. Furthermore, in the blade segment 100 according to the fifth embodiment, at least some of the multiple fourth cooling holes 184 are connected to the suction side second side passage 132s. This allows cooling air from the second circumferential passage 122 to be supplied to the fourth cooling holes 184 via the suction side second side passage 132s. Note that all of the multiple fourth cooling holes 184 may be connected to the second circumferential passage 122, or all of the multiple fourth cooling holes 184 may be connected to the suction side second side passage 132s.

[0076] The present disclosure is not limited to the above-described embodiments and includes modifications of the above-described embodiments and appropriate combinations of these embodiments. For example, one or more of the above-described embodiments may be implemented in a single blade segment 100, or different embodiments may be implemented for each blade segment 100. Furthermore, in the case of different embodiments that are applied to the same location but different from each other, such as the fourth and fifth embodiments, in a single blade segment 100, for example, the fourth embodiment may be implemented with respect to the supply of cooling air to the first cooling hole 181 and the fourth cooling hole 184, and the fifth embodiment may be implemented with respect to the supply of cooling air to the second cooling hole 182 and the third cooling hole 183. In this way, different embodiments may be implemented depending on the application location.

[0077] The present disclosure is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0078] The contents of the above embodiments can be understood, for example, as follows. (1) A blade segment 100 according to at least one embodiment of the present disclosure includes a first segment 101A including one first airfoil 23A, a first outer shroud 27A provided on the outer side of the first airfoil 23A in the blade height direction, and a first inner shroud 25A provided on the inner side of the first airfoil 23A in the blade height direction. The blade segment 100 according to at least one embodiment of the present disclosure includes a second segment 101B including one second airfoil 23B, a second outer shroud 27B provided on the outer side of the second airfoil 23B in the blade height direction, and a second inner shroud 25B provided on the inner side of the second airfoil 23B in the blade height direction. The first outer shroud 27A and the second outer shroud 27B are connected by bolts. The first inner shroud 25A and the second inner shroud 25B are connected with bolts. The first outer shroud 27A has a first side portion (suction-side first end portion 151As) where a first side surface 191 facing the second outer shroud 27B is formed. The second outer shroud 27B has a second side portion (pressure-side second end portion 151Bp) where a second side surface 192 facing the first outer shroud 27A is formed. In the first side portion (suction-side first end portion 151As), a region R1 on the leading edge 23a side of the first airfoil portion 23A is provided with at least one first cooling hole 181 that opens toward a space sandwiched between the first outer shroud 27A and the first inner shroud 25A and through which cooling air can flow. In the second side portion (ventral side second side end portion 151Bp), a region R2 on the leading edge 23a side of the second airfoil portion 23B is provided with at least one second cooling hole 182 through which cooling air can flow, which opens toward the space sandwiched between the second outer shroud 27B and the second inner shroud 25B.

[0079] In the blade segment 100 in which the first segment 101A and the second segment 101B are bolted together, the regions R1 and R2 on the leading edge 23a side of the first side portion (suction side first end portion 151As) and the second side portion (ventral side second end portion 151Bp) tend to have higher temperatures than the regions on the trailing edge 23b side, which means that thinning is likely to occur in the regions on the leading edge 23a side of the first side surface 191 and the second side surface 192. According to the configuration (1) above, by providing the first cooling holes 181 and the second cooling holes 182 in the regions R1 and R2 on the leading edge 23a side of the first side portion (suction side first end portion 151As) and the second side portion (ventral side second end portion 151Bp), it is possible to effectively cool the regions R1 and R2 on the leading edge 23a side of the first side portion (suction side first end portion 151As) and the second side portion (ventral side second end portion 151Bp). This reduces the thickness reduction in the region of the first side surface 191 and the second side surface 192 on the front edge 23a side.

[0080] (2) In some embodiments, in the configuration of (1) above, the first side surface 191 may include a first coating region 231 in which an oxidation-resistant coating is applied to at least a portion of a region of the first side surface 191 that is closer to the leading edge 23 a of the first airfoil portion 23A. The second side surface 192 may include a second coating region 232 in which an oxidation-resistant coating is applied to at least a portion of a region of the second side surface 192 that is closer to the leading edge 23 a of the second airfoil portion 23B. The first coating region 231 and the second coating region 232 may face each other in the direction in which the first outer shroud 27A and the second outer shroud 27B are aligned (the circumferential direction Dc).

[0081] According to the above configuration (2), it is possible to reduce the thinning of the first coating region 231 and the second coating region 232 .

[0082] (3) In some embodiments, in the configuration of (2) above, the first coating region 231 may be formed in a region of the first side surface 191 from the end 191a on the leading edge 23a side of the first airfoil portion 23A to a position a specified distance a1 away from the end 191a toward the trailing edge 23b of the first airfoil portion 23A, and also in a region of the first side surface 191 from the end 191b on the inner side in the wing height direction of the first airfoil portion 23A to a position a specified distance a2 away from the end 191b toward the outer side in the wing height direction of the first airfoil portion 23A.

[0083] In the above configuration (3), the region where the first coating region 231 is formed is a region where thinning is relatively likely to occur on the first side surface 191. According to the above configuration (3), the first coating region 231 is formed in a region where thinning is relatively likely to occur on the first side surface 191, so thinning on the first side surface 191 can be effectively reduced.

[0084] (4) In some embodiments, in the configuration of (2) or (3) above, the second coating region 232 may be formed in a region of the second side surface 192 from the end 192a on the leading edge 23a side of the second airfoil portion 23B to a position a specified distance a3 away from the end 192a toward the trailing edge 23b of the second airfoil portion 23B, and in a region of the second side surface 192 from the end 192b on the inner side in the wing height direction of the second airfoil portion 23B to a position a specified distance a4 away from the end 192b toward the outer side in the wing height direction of the second airfoil portion 23B.

[0085] In the configuration (4) above, the region where the second coating region 232 is formed is a region where thinning is relatively likely to occur on the second side surface 192. According to the configuration (4) above, the second coating region 232 is formed in a region where thinning is relatively likely to occur on the second side surface 192, so thinning on the second side surface 192 can be effectively reduced.

[0086] (5) In some embodiments, in any of the configurations (1) to (4) above, the first outer shroud 27A may have a first chamfered portion 221 formed by chamfering a corner 201 at which the first side surface 191, a leading-edge-side first side surface 211 facing the leading edge 23a of the first airfoil portion 23A among the side surfaces of the first outer shroud 27A, and a first gas path surface 27a1 facing the space sandwiched between the first outer shroud 27A and the first inner shroud 25A intersect. The second outer shroud 27B may have a second chamfered portion 222 that chamfers a corner 202 where a second side surface 192, a leading edge side second side surface 212 facing the leading edge 23a of the second airfoil portion 23B among the side surfaces of the second outer shroud 27B, and a second gas path surface 27a2 facing the space sandwiched between the second outer shroud 27B and the second inner shroud 25B intersect.

[0087] In the configuration of (5) above, the corners 201 of the first outer shroud 27A and the corners 202 of the second outer shroud 27B are portions that are difficult to cool and relatively prone to thinning. According to the configuration of (5) above, the corners 201, 202, which are relatively prone to thinning, are chamfered, so that thinning can be effectively suppressed.

[0088] (6) In some embodiments, in the configuration of (5) above, when viewed from the blade height direction of the first airfoil portion 23A, the intersection angle θ1 between the first side surface 191 and the leading-edge-side first side surface 211 may be an acute angle. At least one of the first cooling holes 181 may open to the first chamfered portion 221.

[0089] When the intersection angle θ1 between the first side surface 191 and the leading-edge-side first side surface 211 is an acute angle, it is more difficult to form the cooling holes (first cooling holes 181) near the corners where the first side surface 191 and the leading-edge-side first side surface 211 intersect than when the intersection angle θ1 is an obtuse angle. According to the configuration (6) above, it is easier to form the cooling holes (first cooling holes 181) in chamfered portions such as the first chamfered portion 221, making it easier to form the first cooling holes 181. This allows the first cooling holes 181 to be formed in areas that are difficult to cool and relatively prone to thinning, thereby effectively suppressing thinning.

[0090] (7) In some embodiments, in any of the configurations (1) to (6) above, the first outer shroud 27A may extend in a direction (circumferential direction Dc) in which the first outer shroud 27A and the second outer shroud 27B are aligned on the leading edge 23 a side of the first airfoil portion 23A, and a space sandwiched between the first outer shroud 27A and the first inner shroud 25A may have a leading-edge-side first air passage (first circumferential passage 121) through which cooling air supplied from an outer first space (space portion 157) on the opposite side of the first outer shroud 27A can flow. The first outer shroud 27A may have a first supply passage 241 different from the leading-edge-side first air passage (first circumferential passage 121) configured to be able to supply the cooling air supplied from the outer first space (space portion 157) to the first cooling holes 181.

[0091] According to the configuration of (7) above, by supplying cooling air from the first supply passage 241 to the first cooling holes 181, it is easier to ensure the flow rate of cooling air supplied to the first cooling holes 181, and the region R1 on the leading edge 23 a side of the first side portion (back-side first lateral end portion 151As) can be effectively cooled. This effectively reduces thinning of the region on the leading edge 23 a side of the first side surface 191.

[0092] (8) In some embodiments, in any of the configurations (1) to (7) above, the second outer shroud (27B) may extend in the direction in which the first outer shroud (27A) and the second outer shroud (27B) are aligned (the circumferential direction Dc) on the leading edge (23a) side of the second airfoil portion (23B), and a space sandwiched between the second outer shroud (27B) and the second inner shroud (25B) may have a leading-edge-side second air passage (second circumferential passage 122) through which cooling air supplied from an outer second space (space portion 157) on the opposite side of the second outer shroud (27B) can flow. The second outer shroud (27B) may have a second supply passage (242) different from the leading-edge-side second air passage (second circumferential passage 122) configured to be able to supply the cooling air supplied from the outer second space (space portion 157) to the second cooling holes (182).

[0093] According to the configuration of (8) above, by supplying cooling air from the second supply passage 242 to the second cooling holes 182, it is easier to ensure the flow rate of cooling air supplied to the second cooling holes 182, and the region R2 on the leading edge 23 a side of the second side portion (ventral-side second lateral end portion 151Bp) can be effectively cooled. This makes it possible to effectively reduce thinning of the region on the leading edge 23 a side of the second side surface 192.

[0094] (9) In some embodiments, in any of the configurations (1) to (6) above, the first outer shroud 27A may extend in the direction in which the first outer shroud 27A and the second outer shroud 27B are aligned (the circumferential direction Dc) on the leading edge 23a side of the first airfoil portion 23A, and the space sandwiched between the first outer shroud 27A and the first inner shroud 25A may have a leading-edge-side first air passage (first circumferential passage 121) through which cooling air supplied from an outer first space (space portion 157) on the opposite side across the first outer shroud 27A can flow. The first cooling holes 181 may be connected to the leading-edge-side first air passage (first circumferential passage 121).

[0095] According to the above configuration (9), cooling air can be supplied to the first cooling holes 181 from the leading-edge-side first air passage (first circumferential passage 121).

[0096] (10) In some embodiments, in any of the configurations (1) to (6) or (9) above, the second outer shroud (27B) may extend in the direction in which the first outer shroud (27A) and the second outer shroud (27B) are aligned (the circumferential direction Dc) on the leading edge (23a) side of the second airfoil portion (23B), and the space sandwiched between the second outer shroud (27B) and the second inner shroud (25B) may have a leading-edge-side second air passage (the second circumferential passage 122) through which cooling air supplied from an outer second space (the space 157) on the opposite side across the second outer shroud (27B) can flow. The second cooling holes (182) may be connected to the leading-edge-side second air passage (the second circumferential passage 122).

[0097] According to the above configuration (10), cooling air can be supplied to the second cooling holes 182 from the leading-edge-side second air passage (the second circumferential passage 122).

[0098] (11) In some embodiments, in any of the configurations (1) to (10) above, the first outer shroud 27A may have a third side portion (ventral-side first end portion 151Ap) where a third side surface 193 is formed on the opposite side of the first side surface 191 across the first airfoil portion 23A. The second outer shroud 27B may have a fourth side portion (suction-side second end portion 151Bs) where a fourth side surface 194 is formed on the opposite side of the second side surface 192 across the second airfoil portion 23B. In the third side portion (ventral-side first end portion 151Ap), a region R3 on the leading edge 23a side of the first airfoil portion 23A may be provided with at least one third cooling hole 183 that opens toward a space sandwiched between the first outer shroud 27A and the first inner shroud 25A and through which cooling air can flow. In the fourth side portion (suction side second side end portion 151Bs), a region R4 on the leading edge 23a side of the second airfoil portion 23B may be provided with at least one fourth cooling hole 184 through which cooling air can flow, which opens toward the space sandwiched between the second outer shroud 27B and the second inner shroud 25B.

[0099] According to the configuration of (11) above, by providing the third cooling holes 183 and the fourth cooling holes 184 in the regions R3 and R4 on the leading edge 23a side of the third side portion (ventral side first end portion 151Ap) and the fourth side portion (dorsal side second end portion 151Bs), it is possible to effectively cool the regions R3 and R4 on the leading edge 23a side of the third side portion (ventral side first end portion 151Ap) and the fourth side portion (dorsal side second end portion 151Bs). This makes it possible to reduce thinning of the regions on the leading edge 23a side of the third side surface 193 and the fourth side surface 194.

[0100] (12) A gas turbine 10 according to at least one embodiment of the present disclosure includes a rotor 14 and a stator blade ring 20 in which a plurality of blade segments 100 having any of the configurations described above in (1) to (11) are arranged in the circumferential direction Dc of the rotor 14.

[0101] According to the configuration (12) above, it is possible to reduce thinning of the area of ​​the leading edge 23a of the first side surface 191 and the second side surface 192 of the blade segment 100, thereby reducing the frequency of replacement of the blade segment 100 and reducing the maintenance costs of the gas turbine 10.

[0102] 2 Shroud 10 Gas turbine 11 Compressor 12 Combustor 13 Turbine 14 Rotor 15 Generator 20 Stator blade ring 21 Turbine stator blade (stator blade) 23 Airfoil section 23A First airfoil section 23B Second airfoil section 23a Leading edge 23b Trailing edge 23c Pressure side airfoil surface 23d Suction side airfoil surface 25 Inner shroud 25A First inner shroud 25B Second inner shroud 27 Outer shroud 27A First outer shroud 27a1 First gas path surface 27a2 Second gas path surface 27B Second outer shroud 32 Combustion gas flow path 100 Blade segment 101 Segment 101A First segment 101B Second segment 111 First opening 112 Opening 121 First circumferential passage 122 Second circumferential passage 131p Ventral first side passage 131s Dorsal first side passage 132p Ventral second side passage 132s Dorsal second side passage 141p First ventral connecting passage 141s First dorsal connecting passage 142p Second ventral connecting passage 142s Second dorsal connecting passage 151A First side end 151Ap Ventral first side end 151As Dorsal first side end 151B Second side end 151Bp Ventral second side end 151Bs Dorsal second side end 153A First leading edge end 153B Second leading edge end 154A First trailing edge end 154B Second trailing edge end 155 Outer region 155a Outer region bottom surface 157 Space portion 158A First side end 158B Second side end 181 First cooling hole 182 Second cooling hole 183 Third cooling hole 184 Fourth cooling hole 191 First side 191a End 191b End 192 Second side 192a End 192b End 193 Third side 194 Fourth side 201 Corner 202 Corner 211 Leading edge side first side 212 Leading edge side second side 221 First chamfered portion 222 Second chamfered portion 231 First coating area 232 Second coating area 241 First supply passage 241a Inlet opening 242 Second supply passage 242a Inlet opening 234 Third supply passage 243a Inlet opening 244 Fourth supply passage 244a Inlet opening 251p First ventral cavity 251s First dorsal cavity 252p Second ventral cavity 252s Second dorsal cavity

Claims

1. A first segment including a first airfoil, a first outer shroud provided on the outer side of the first airfoil in the airfoil height direction, and a first inner shroud provided on the inner side of the first airfoil in the airfoil height direction; and a second segment including a second airfoil, a second outer shroud provided on the outer side of the second airfoil in the airfoil height direction, and a second inner shroud provided on the inner side of the second airfoil in the airfoil height direction; wherein the first outer shroud and the second outer shroud are bolted together, and the first inner shroud and the second inner shroud are bolted together, the first outer shroud has a first side portion formed with a first side surface facing the second outer shroud, and the second outer shroud has a second side portion formed with a second side surface facing the first outer shroud, A blade segment, wherein a leading edge region of the first airfoil portion on the first side is provided with at least one first cooling hole through which cooling air can flow, the first cooling hole opening toward a space sandwiched between the first outer shroud and the first inner shroud, and a leading edge region of the second airfoil portion on the second side is provided with at least one second cooling hole through which cooling air can flow, the second cooling hole opening toward a space sandwiched between the second outer shroud and the second inner shroud.

2. The blade segment according to claim 1, wherein the first side includes a first coating region in which an oxidation-resistant coating is applied to at least a portion of a region of the first side that is on the leading edge side of the first airfoil section, and the second side includes a second coating region in which an oxidation-resistant coating is applied to at least a portion of a region of the second side that is on the leading edge side of the second airfoil section, and the first coating region and the second coating region face each other in a direction in which the first outer shroud and the second outer shroud are aligned.

3. A blade segment as claimed in claim 2, wherein said first coating region is formed in a region of said first side surface from an end of said first airfoil portion on the leading edge side to a position a specified distance from said end toward the trailing edge side of said first airfoil portion, and also in a region of said first side surface from an end of said first airfoil portion on the inner side in the blade height direction to a position a specified distance from said end toward the outer side in the blade height direction of said first airfoil portion.

4. A blade segment as claimed in claim 2 or 3, wherein the second coating region is formed in a region of the second side surface from an end of the second airfoil portion on the leading edge side to a position a specified distance from said end toward the trailing edge side of the second airfoil portion, and also in a region of the second side surface from an end of the second airfoil portion on the inner side in the blade height direction to a position a specified distance from said end toward the outer side in the blade height direction of the second airfoil portion.

5. The blade segment according to any one of claims 1 to 3, wherein the first outer shroud has a first chamfered portion chamfered at a corner where the first side surface, a leading-edge-side first side surface of the side surface of the first outer shroud facing the leading edge of the first airfoil portion, and a first gas path surface facing the space sandwiched between the first outer shroud and the first inner shroud intersect, and the second outer shroud has a second chamfered portion chamfered at a corner where the second side surface, a leading-edge-side second side surface of the side surface of the second outer shroud facing the leading edge of the second airfoil portion, and a second gas path surface facing the space sandwiched between the second outer shroud and the second inner shroud intersect.

6. A blade segment as set forth in claim 5, wherein, when viewed in a blade height direction of said first airfoil section, an intersection angle between said first side surface and said leading edge first side surface is an acute angle, and at least one of said first cooling holes opens into said first chamfered portion.

7. A blade segment as claimed in any one of claims 1 to 3, wherein the first outer shroud extends in a direction in which the first outer shroud and the second outer shroud are aligned on the leading edge side of the first airfoil portion, and the space sandwiched between the first outer shroud and the first inner shroud has: a leading edge side first air passage through which cooling air supplied from an outer first space on the opposite side of the first outer shroud can flow; and a first supply passage different from the leading edge side first air passage and configured to be able to supply cooling air supplied from the outer first space to the first cooling hole.

8. A blade segment as claimed in any one of claims 1 to 3, wherein the second outer shroud extends in a direction in which the first outer shroud and the second outer shroud are aligned on the leading edge side of the second airfoil portion, and the space sandwiched between the second outer shroud and the second inner shroud has: a leading edge side second air passage through which cooling air supplied from an outer second space on the opposite side of the second outer shroud can flow; and a second supply passage different from the leading edge side second air passage, configured to be able to supply cooling air supplied from the outer second space to the second cooling hole.

9. A blade segment as claimed in any one of claims 1 to 3, wherein the first outer shroud extends in a direction in which the first outer shroud and the second outer shroud are aligned on the leading edge side of the first airfoil portion, and the space sandwiched between the first outer shroud and the first inner shroud has a leading edge side first air passage through which cooling air supplied from an outer first space on the opposite side across the first outer shroud can flow, and the first cooling hole is connected to the leading edge side first air passage.

10. A blade segment as claimed in any one of claims 1 to 3, wherein the second outer shroud extends in a direction in which the first outer shroud and the second outer shroud are aligned on the leading edge side of the second airfoil portion, and the space sandwiched between the second outer shroud and the second inner shroud has a leading edge side second air passage through which cooling air supplied from an outer second space on the opposite side across the second outer shroud can flow, and the second cooling hole is connected to the leading edge side second air passage.

11. A blade segment as claimed in any one of claims 1 to 3, wherein the first outer shroud has a third side formed with a third side surface opposite the first side surface across the first airfoil, the second outer shroud has a fourth side formed with a fourth side surface opposite the second side surface across the second airfoil, an area on the third side facing the leading edge of the first airfoil is provided with at least one third cooling hole opening toward a space sandwiched between the first outer shroud and the first inner shroud and through which cooling air can flow, and an area on the fourth side facing the leading edge of the second airfoil is provided with at least one fourth cooling hole opening toward a space sandwiched between the second outer shroud and the second inner shroud and through which cooling air can flow.

12. A gas turbine comprising: a rotor; and a stator blade ring in which a plurality of blade segments according to any one of claims 1 to 3 are arranged in the circumferential direction of the rotor.