Gas turbine casing and gas turbine including the same

Abstract

To improve the durability of a gas turbine casing while suppressing the enlargement of the gas turbine casing.SOLUTION: The gas turbine casing includes a combustor attachment portion. The combustor attachment part has an attachment part outer peripheral surface and an attachment part inner peripheral surface that is in a back-to-back relationship with the attachment part outer peripheral surface and defines an edge of a part of an internal space. The mounting section inner peripheral surface gradually spreads radially outward with respect to the rotor axis toward the axial downstream side with respect to the rotor axis. The combustor attachment part further includes a plurality of combustor insertion holes arranged at intervals in a circumferential direction with respect to the rotor axis and penetrating from the attachment part outer peripheral surface to the attachment part inner peripheral surface, an inter-hole portion between the plurality of combustor insertion holes, and a groove recessed from the attachment part inner peripheral surface toward the attachment part outer peripheral surface in a region in the circumferential direction where the inter-hole portion is present and in a region on an inner side of the inter-hole portion in a radial direction with respect to the rotor axis.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a gas turbine casing and a gas turbine including the same. [Background technology]

[0002] A gas turbine includes a compressor capable of compressing air, a plurality of combustors capable of burning fuel in the air compressed by the compressor to generate combustion gas, a turbine capable of being driven by the combustion gas, and an intermediate casing.

[0003] The compressor has a compressor rotor rotatable about a rotor axis and a compressor casing that covers the compressor rotor. The turbine has a turbine rotor rotatable about a rotor axis and a turbine casing that covers the turbine rotor. Here, the direction in which the rotor axis extends is referred to as the rotor axial direction, and of the two sides in the rotor axial direction, one side is referred to as the axial upstream side and the other side is referred to as the axial downstream side. Furthermore, the radial direction relative to the rotor axis is simply referred to as the radial direction, and the circumferential direction relative to the rotor axis is simply referred to as the circumferential direction.

[0004] The compressor is disposed axially upstream of the turbine. The compressor rotor and turbine rotor are connected to each other to form a gas turbine rotor. An intermediate casing is disposed between the compressor casing and the turbine casing. The compressor casing, intermediate casing, and turbine casing are connected to each other to form a gas turbine casing. Compressed air discharged from the compressor flows into the internal space of the intermediate casing. Multiple combustors are attached to the intermediate casing and arranged circumferentially.

[0005] The intermediate casing described in Patent Document 1 below has a combustor mounting portion whose internal space radially widens toward the axial downstream side. This combustor mounting portion has a plurality of combustor insertion holes that are arranged at intervals in the circumferential direction and penetrate from the outside into the internal space. Each of the plurality of combustors is inserted into the internal space through one of the plurality of combustor insertion holes. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-243309 Summary of the Invention [Problem to be solved by the invention]

[0007] In recent years, the compression ratio of compressors has been increased to improve gas turbine efficiency. This has resulted in higher compressed air pressure inside the intermediate casing. In this regard, there is a need to improve the durability of the intermediate casing so that it can withstand the increased compressed air pressure. One possible method for improving the durability of the intermediate casing against the increased compressed air pressure is to increase the thickness of the intermediate casing. However, this method increases the size and weight of the intermediate casing.

[0008] Therefore, an object of the present disclosure is to provide a gas turbine casing that can improve durability while suppressing an increase in size, and a gas turbine including the same. [Means for solving the problem]

[0009] A gas turbine casing as one mode for achieving the above object has an internal space in which a gas turbine rotor rotatable about a rotor axis is disposed. The gas turbine casing includes a combustor mounting portion and a combustion liner opposing portion. The combustion liner opposing portion is an end of the combustor mounting portion and is connected to the downstream end of the combustor mounting portion between an upstream side and a downstream side in a rotor axial direction in which the rotor axis extends. The combustor mounting portion has a mounting portion outer circumferential surface and a mounting portion inner circumferential surface that is back-to-back with the mounting portion outer circumferential surface and defines an edge of a portion of the internal space. The mounting portion inner circumferential surface gradually widens radially outward as it extends toward the downstream side of the axis. The combustion liner opposing portion has a facing portion outer circumferential surface that is continuous with the mounting portion outer circumferential surface, and a facing portion inner circumferential surface that is back-to-back with the facing portion outer circumferential surface and is continuous with the mounting portion inner circumferential surface and defines a portion of the internal space that is continuous with the portion of the internal space defined by the mounting portion inner circumferential surface. Among the mounting portion inner peripheral surface and the opposing portion inner peripheral surface, a boundary portion inner peripheral surface including a boundary between the mounting portion inner peripheral surface and the opposing portion inner peripheral surface is a curved surface in which an amount of positional change to the radially outward direction accompanying a positional change to the axial downstream side gradually decreases. The combustor mounting portion further includes a plurality of combustor insertion holes that are arranged at intervals in a circumferential direction about the rotor axis and that penetrate from the mounting portion outer peripheral surface to the mounting portion inner peripheral surface, inter-hole portions that are between every two combustor insertion holes adjacent to each other in the circumferential direction among the plurality of combustor insertion holes, and grooves that are recessed from the mounting portion inner peripheral surface toward the mounting portion outer peripheral surface in a circumferential region where the inter-hole portions are present, the inter-hole portions being located radially inward from the inter-hole portions in the radial direction.

[0010] During operation of a gas turbine, stresses specific to this operation are generated in the gas turbine casing. Assume that the extension direction of the combustor mounting portion differs from the extension direction of the combustion liner facing portion connected to the axial downstream end of the combustor mounting portion, and the inner circumferential surface of the boundary portion, including the boundary between the inner circumferential surface of the mounting portion and the inner circumferential surface of the facing portion, is a curved surface in which the amount of radial outward positional change gradually decreases with the change in position toward the axial downstream side. In this case, the position of peak stress, which is the maximum stress among the stresses at each position in the thickness direction at the boundary portion between the combustor mounting portion and the combustion liner facing portion, tends to be closer to the inner circumferential surface of the boundary portion. If the position of this peak stress is significantly closer to the inner circumferential surface of the boundary portion, the stress distribution in the thickness direction at this boundary portion will be significantly biased toward the inner circumferential surface of the boundary portion. As a result, the peak stress at the boundary portion will be extremely large.

[0011] The gas turbine casing according to this aspect has a groove recessed from the inner peripheral surface of the attachment portion toward the outer peripheral surface of the attachment portion in a region radially inward of the inter-hole portion. The presence of this groove shifts the position of peak stress in the thickness direction in a region radially outward of the groove toward the outer peripheral surface of the attachment portion compared to a case in which the groove is absent. As a result, the peak stress in the thickness direction at the boundary portion also shifts toward the outer peripheral surface of the attachment portion, and the stress distribution in the thickness direction at the boundary portion is more averaged than in a case in which the groove is absent. Therefore, according to this aspect, the magnitude of the peak stress in the thickness direction at the boundary portion can be suppressed.

[0012] A gas turbine according to one aspect for achieving the above object includes: the gas turbine casing according to the above aspect; the gas turbine rotor; and a combustor having a combustor portion inserted into each of the plurality of combustor insertion holes and fixed to the combustor mounting portion. [Effects of the Invention]

[0013] In one aspect of the present disclosure, the durability of the gas turbine casing can be improved while suppressing an increase in size of the gas turbine casing. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic configuration diagram of a gas turbine facility according to an embodiment of the present disclosure. FIG. [Figure 2] 1 is a cross-sectional view of a main portion of a gas turbine around a combustor in an embodiment according to the present disclosure. FIG. [Figure 3] 1 is a cross-sectional view of a main portion of a gas turbine around a space between two combustors in a first embodiment according to the present disclosure. FIG. [Figure 4] FIG. 4 is a view taken along the arrow IV in FIG. [Figure 5] FIG. 4 is an explanatory diagram illustrating stress distribution in an intermediate casing according to an embodiment of the present disclosure. [Figure 6] FIG. 10 is an explanatory diagram showing stress distribution in an intermediate casing in a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of a gas turbine facility including a gas turbine casing according to the present invention will be described with reference to the drawings.

[0016] As shown in FIG. 1, the gas turbine facility of this embodiment includes a gas turbine 10 and a cooling air supply device 1 that can supply cooling air Acl to some of the components of the gas turbine 10.

[0017] The gas turbine 10 includes a compressor 20 capable of compressing air A to generate compressed air Acom, a plurality of combustors 30 capable of burning fuel F in the compressed air Acom to generate combustion gas G, a turbine 40 capable of being driven by the high-temperature, high-pressure combustion gas G, an exhaust casing 19 through which exhaust gas EG, which is the combustion gas G exhausted from the turbine 40, can flow, an intermediate casing 13, and an intermediate shaft cover 50.

[0018] The compressor 20 includes a compressor rotor 21 rotatable about a rotor axis Ar, a compressor casing 24 covering the compressor rotor 21, multiple compressor stator vane rows 25, and a diffuser 26. The turbine 40 includes a turbine rotor 41 rotatable about the rotor axis Ar, a turbine casing 44 covering the turbine rotor 41, and multiple turbine stator vane rows 45. Here, the direction in which the rotor axis Ar extends is referred to as the rotor axial direction Da, the circumferential direction centered on the rotor axis Ar is simply referred to as the circumferential direction Dc, and the direction perpendicular to the rotor axis Ar is referred to as the radial direction Dr. One side of the rotor axial direction Da is referred to as the axial upstream side Dau, and the opposite side is referred to as the axial downstream side Dad. The side of the radial direction Dr closer to the rotor axis Ar is referred to as the radially inner side Dri, and the opposite side is referred to as the radially outer side Dro.

[0019] The compressor 20 is disposed on the axial upstream side Dau with respect to the turbine 40. The exhaust casing 19 is disposed on the axial downstream side Dad with respect to the turbine 40.

[0020] The compressor rotor 21 has a compressor rotor shaft 22 that extends in the rotor axial direction Da around the rotor axis Ar, and a plurality of compressor rotor blade rows 23 attached to the compressor rotor shaft 22. The plurality of compressor rotor blade rows 23 are aligned in the rotor axial direction Da. Each compressor rotor blade row 23 is composed of a plurality of rotor blades aligned in the circumferential direction Dc. One of a plurality of compressor stator vane rows 25 is arranged on the axial downstream side Dad of each of the plurality of compressor rotor blade rows 23. Each compressor stator vane row 25 is provided inside the compressor casing 24. Each compressor stator vane row 25 is composed of a plurality of stator vanes aligned in the circumferential direction Dc.

[0021] The diffuser 26 forms a diffuser space through which air passes after passing through the plurality of compressor rotor blade rows 23. This diffuser space is an annular space centered on the rotor axis Ar.

[0022] The turbine rotor 41 has a turbine rotor shaft 42 that extends in the rotor axial direction Da around the rotor axis Ar, and a plurality of turbine rotor blade rows 43 attached to the turbine rotor shaft 42. The plurality of turbine rotor blade rows 43 are aligned in the rotor axial direction Da. Each turbine rotor blade row 43 is composed of a plurality of rotor blades aligned in the circumferential direction Dc. One of a plurality of turbine stator blade rows 45 is arranged on the axial upstream side Dau of each of the plurality of turbine rotor blade rows 43. Each turbine stator blade row 45 is provided inside a turbine casing 44. Each turbine stator blade row 45 is composed of a plurality of stator blades aligned in the circumferential direction Dc. An annular space between the outer circumferential side of the turbine rotor shaft 42 and the inner circumferential side of the turbine casing 44 forms a combustion gas flow path 49 through which combustion gas G flows. The plurality of turbine stator blade rows 45 and a plurality of turbine rotor blade rows 43 are arranged in this combustion gas flow path 49.

[0023] The compressor rotor 21 and the turbine rotor 41 are located on the same rotor axis Ar and are connected to each other to form the gas turbine rotor 11. The gas turbine rotor 11 thus has a gas turbine rotor shaft 11s that extends in the rotor axial direction Da around the rotor axis Ar, a plurality of compressor rotor blade rows 23, and a plurality of turbine rotor blade rows 43. An intermediate rotor shaft 11m is formed in the gas turbine rotor shaft 11s between the plurality of compressor rotor blade rows 23 and the plurality of turbine rotor blade rows 43. A rotor of a generator 9, for example, is connected to the gas turbine rotor 11. The intermediate casing 13 is disposed between the compressor casing 24 and the turbine casing 44 in the rotor axial direction Da and covers the intermediate rotor shaft 11m. Compressed air Acom discharged from the diffuser 26 of the compressor 20 flows into the intermediate casing 13. The compressor casing 24 , the intermediate casing 13 , the turbine casing 44 and the exhaust casing 19 are connected to one another to form the gas turbine casing 12 .

[0024] The intermediate shaft cover 50 is disposed inside the intermediate casing 13 and covers the outer peripheral side of the intermediate rotor shaft 11m.

[0025] The plurality of combustors 30 are attached to the intermediate casing 13 and arranged in the circumferential direction Dc.

[0026] The cooling air supply device 1 has an extraction line 2 for extracting the compressed air Acom from the intermediate casing 13, a cooler 3 for cooling the compressed air Acom that has flowed through the extraction line 2, a cooling air line 4 for guiding the cooling air Acl, which is the compressed air Acom cooled by the cooler 3, to the turbine rotor shaft 42, and a boost compressor 5 for compressing the cooling air Acl flowing through the cooling air line 4.

[0027] The compressor 20 draws in external air A and compresses it to generate compressed air Acom. This compressed air Acom is discharged from the diffuser 26 of the compressor 20 into the intermediate casing 13. The compressed air Acom in the intermediate casing 13 flows into the combustor 30. In the combustor 30, fuel F sent from the outside is combusted in the compressed air Acom to produce combustion gas G. This combustion gas G is sent to a combustion gas flow path 49 of the turbine 40 and rotates the turbine rotor 41.

[0028] The compressed air Acom in the intermediate casing 13 is cooled by the cooling air supply device 1 and supplied as cooling air Acl to the turbine rotor blade row 43. The multiple rotor blades of this turbine rotor blade row 43 are cooled by this cooling air Acl.

[0029] Next, the intermediate casing 13, the combustor 30 attached to the intermediate casing 13, and the components disposed inside the intermediate casing 13 will be described in detail with reference to Figures 2 to 4. Figure 2 is a cross-sectional view of a main part of the gas turbine 10 around the combustor 30, taken along an imaginary plane that includes the rotor axis Ar and crosses the combustor 30. Figure 3 is a cross-sectional view of a main part of the gas turbine 10 around the combustor 30, taken along an imaginary plane that includes the rotor axis Ar and crosses the space between the two combustors 30. Figure 4 is a view taken along arrow IV in Figure 3.

[0030] As shown in FIG. 2 , the combustor 30 includes a cylindrical combustion liner (or transition piece) 32 arranged around the combustor axis Ab, a plurality of nozzles capable of injecting fuel F into the combustion liner 32, an inner liner covering the outer peripheries of the plurality of nozzles, a mounting flange 35 attached to the intermediate casing 13, and a nozzle base 34 fixed to the mounting flange 35.

[0031] Here, the direction in which the combustor axis Ab extends is referred to as a combustor axial direction Db. Furthermore, one of both sides in the combustor axial direction Db is referred to as a base end side Dbb, and the other side is referred to as a tip side Dbt. The combustor axis Ab of each combustor 30 extends within an imaginary plane that includes the rotor axis Ar. The combustor axis Ab is inclined with respect to the rotor axis Ar so as to gradually approach the rotor axis Ar as it extends toward the tip side Dbt.

[0032] A base end side Dbb of the multiple nozzles is fixed to a nozzle base 34. The inner cylinder is cylindrical around the combustor axis Ab and covers the outer periphery of the multiple nozzles. A combustion cylinder 32 is connected to a tip end side Dbt of the inner cylinder. A mounting flange 35 is fixed to the base end side Dbb of the nozzle base 34. This mounting flange 35 protrudes from the nozzle base 34 in a radial direction with respect to the combustor axis Ab. This mounting flange 35 is disposed outside the intermediate casing 13 and is fixed to the intermediate casing 13 with bolts or the like. The combustion cylinder 32 is supported by cylinder support legs (stationary components) 39 that are fixed to the intermediate casing 13.

[0033] The diffuser 26 of the compressor 20 has an inner diffuser 26i, an outer diffuser 26o, a cooling air jacket 27, and a diffuser support leg 28.

[0034] The inner diffuser 26i is cylindrical and centered on the rotor axis Ar, defining the inner edge of the annular diffuser space. The outer diffuser 26o is cylindrical and centered on the rotor axis Ar, defining the outer edge of the annular diffuser space. The cooling air jacket 27 defines a cooling air space on the outer circumferential side of the outer diffuser 26o and on the axial downstream side Dad of the outer diffuser 26o. The cooling air line 4 of the cooling air supply device 1 is connected to the cooling air jacket 27. Cooling air Acl from the cooling air line 4 can flow into the cooling air space within the cooling air jacket 27. The diffuser support legs 28 extend from the outer circumferential surface of the outer diffuser 26o radially outward (Dro) and gradually toward the axial downstream side Dad. The diffuser support legs (stationary components) 28 are fixed to the intermediate casing 13.

[0035] The intermediate shaft cover 50 has a cover body 51 and a plurality of struts 52. The cover body 51 is cylindrical and centered on the rotor axis Ar, and covers the outer peripheral side of the intermediate rotor shaft 11m. An end of the cover body 51 on the downstream axial side Dad is connected to the inner diffuser 26i. The plurality of struts 52 are arranged at intervals from one another in the circumferential direction Dc. Radially inner ends Dri of the plurality of struts 52 are fixed to the cover body 51. Radially outer ends Dro of the struts 52 are connected to the cooling air jacket 27. A passage is formed in the struts 52 that can guide the cooling air Acl that has flowed into the cooling air jacket 27 to the inside of the cover body 51.

[0036] The cooling air Acl from the cooling air line 4 of the cooling air supply device 1 is supplied to the turbine rotor blade row 43 via the cooling air jacket 27 and the inside of the intermediate shaft cover 50. The multiple rotor blades of this turbine rotor blade row 43 are cooled by this cooling air Acl.

[0037] The intermediate casing 13 has a combustor mounting portion 14 and a combustion liner opposing portion 18 .

[0038] The combustor mounting portion 14 has a mounting portion inner circumferential surface 14i that defines an internal space shaped corresponding to a portion of a cone whose center axis is the rotor axis Ar. This internal space gradually widens in the radial direction Dr toward the axial downstream side Dad. The surface shape of the mounting portion inner circumferential surface 14i and the surface shape of the mounting portion outer circumferential surface 14o, which is back-to-back with the mounting portion inner circumferential surface 14i, both have shapes corresponding to the outer circumferential surface of a portion of a cone whose center axis is the rotor axis Ar, and gradually widens toward the radially outer side Dro toward the axial downstream side Dad. Therefore, the end of the combustor mounting portion 14 on the axial downstream side Dad is substantially the end of the radially outer side Dro of the combustor mounting portion 14. Furthermore, the end of the combustor mounting portion 14 on the axial upstream side Dau is substantially the end of the radially inner side Dri of the combustor mounting portion 14. The end 13u on the axial upstream side Dau of this combustor mounting portion 14 is also the end 13u on the axial upstream side Dau of the intermediate casing 13. Therefore, the end 13u on the axial upstream side Dau of this combustor mounting portion 14 is connected to the end of the axial downstream side Dad of the compressor casing 24.

[0039] An end portion 13d of the combustion liner facing portion 18 on the axial upstream side Dau is connected to an end portion 13d of the combustor mounting portion 14 on the axial downstream side Dad. An end portion 13d of the combustion liner facing portion 18 on the axial downstream side Dad is also connected to an end portion 13d of the intermediate casing 13 on the axial downstream side Dad. Therefore, the end portion 13d of the combustion liner facing portion 18 on the axial downstream side Dad is connected to an end portion 13d of the turbine casing 44 on the axial upstream side Dau. The combustion liner 32 for each of the multiple combustors 30 is disposed on the inner circumferential side of the combustion liner facing portion 18. The combustion liner facing portion 18 has an inner circumferential surface 18i that defines a substantially cylindrical internal space centered on the rotor axis Ar. The surface shape of the inner circumferential surface 18i and the outer circumferential surface 18o that is back-to-back with the inner circumferential surface 18i both substantially correspond to the outer circumferential surface of a cylinder centered on the rotor axis Ar. The opposing portion inner circumferential surface 18i is continuous with the mounting portion inner circumferential surface 14i. The opposing portion outer circumferential surface 18o is continuous with the mounting portion outer circumferential surface 14o. The inner circumferential surface 13i of the intermediate casing 13 has the mounting portion inner circumferential surface 14i and the opposing portion inner circumferential surface 18i. Furthermore, the outer circumferential surface 13o of the intermediate casing 13 has the mounting portion outer circumferential surface 14o and the opposing portion outer circumferential surface 18o. Within the mounting portion inner circumferential surface 14i and the opposing portion inner circumferential surface 18i, a boundary portion inner circumferential surface 14bi including the boundary between the mounting portion inner circumferential surface 14i and the opposing portion inner circumferential surface 18i is a curved surface in which the amount of positional change toward the radially outward Dro that accompanies a positional change toward the axial downstream side Dad gradually decreases.

[0040] The internal space defined by the combustion liner facing portion 18 is continuous with the internal space defined by the combustor mounting portion 14 to form a single internal space. This single internal space is the internal space of the intermediate casing 13 into which compressed air Acom from the compressor 20 can flow. In other words, of the internal space defined by the intermediate casing 13, the portion on the axial upstream side Dau is the internal space of the combustor mounting portion 14, and the portion on the axial downstream side Dad is the internal space of the combustion liner facing portion 18.

[0041] The combustor mounting portion 14 further has a plurality of combustor insertion holes 15, a plurality of inter-hole portions 15b, a groove 16, and a stationary component mounting portion 17.

[0042] As shown in Fig. 2 and Fig. 4 , the multiple combustor insertion holes 15 are arranged at intervals in the circumferential direction Dc and are holes that penetrate in the combustor axial direction Db from the mounting portion outer peripheral surface 14o to the mounting portion inner peripheral surface 14i. This combustor axial direction Db is the thickness direction of the combustor mounting portion 14. The combustor 30 is inserted into the combustor insertion hole 15 from the outside of the combustor mounting portion 14 and fixed to the combustor mounting portion 14. A nozzle base 34 of the combustor 30 is positioned within the combustor insertion hole 15. A mounting flange 35 of the combustor 30 is fixed in the mounting portion outer peripheral surface 14o of the combustor mounting portion 14 along the edge of the combustor insertion hole 15 with bolts or the like.

[0043] As shown in FIGS. 3 and 4, the inter-hole portion 15b is located between every two combustor insertion holes 15 adjacent to each other in the circumferential direction Dc, among the plurality of combustor insertion holes 15.

[0044] The groove 16 is recessed from the mounting portion inner circumferential surface 14i of the combustor mounting portion 14 toward the mounting portion outer circumferential surface 14o in a region Dri that is radially inward of the combustor insertion holes 15 and the plurality of inter-hole portions 15b. Specifically, the groove 16 is recessed from the mounting portion inner circumferential surface 14i toward a base end side Dbb in the combustor axial direction Db. The groove 16 extends in the circumferential direction Dc and is annular around the rotor axis line Ar.

[0045] The stationary component mounting portion 17 has a first mounting portion 17a located in a region Dri radially inward of the groove 16 and a second mounting portion 17b located in a region Dri radially inward of the first mounting portion 17a. A cylinder support leg 39, which is a type of stationary component, is mounted to the first mounting portion 17a with a bolt or the like. When the cylinder support leg 39 is mounted to the first mounting portion 17a with a bolt, a female threaded hole into which the bolt can be screwed is formed in the first mounting portion 17a. Furthermore, a diffuser support leg 28, which is a type of stationary component, is mounted to the second mounting portion 17b with a bolt or the like. When the diffuser support leg 28 is mounted to the second mounting portion 17b with a bolt, a female threaded hole into which the bolt can be screwed is formed in the second mounting portion 17b. The cylinder support leg 39 and the diffuser support leg 28 are both stationary components disposed radially inward Dri of the multiple combustor insertion holes 15 within the internal space of the intermediate casing 13.

[0046] 3 , a groove width dimension w of the grooves 16 in a direction having a directional component in the radial direction Dr and perpendicular to the combustor axis Ab is smaller than a groove depth dimension d of the grooves 16 in the combustor axis direction Db. Furthermore, the groove depth dimension d is greater than ⅓ of the thickness t of the inter-hole portion 15b in the combustor axis direction Db and is smaller than ⅔ of this thickness t.

[0047] Next, the stress distribution in the intermediate casing 13 will be described with reference to Figures 5 and 6. Figure 5 shows the stress distribution in the intermediate casing 13 in the present embodiment described above. Figure 6 shows the stress distribution in the intermediate casing 13c in a comparative example. The intermediate casing 13c in the comparative example is the same as the intermediate casing 13 in the present embodiment, except that it does not have the grooves 16 of the intermediate casing 13 in the present embodiment. The stress distributions shown in Figures 5 and 6 are stress distributions on the cross sections of the intermediate casings 13, 13c taken along an imaginary plane that includes the rotor axis Ar and crosses between the two combustors 30.

[0048] The stress generated in the intermediate casing 13, 13c varies depending on the position in the thickness direction of the intermediate casing 13, 13c. Therefore, FIGS. 5 and 6 show the stress distribution in the thickness direction at multiple positions A, B, and C in the intermediate casing 13, 13c. Here, the thickness direction based on a predetermined point on the inner circumferential surface 13i of the intermediate casing 13, 13c is the direction of a line segment connecting the predetermined point and a point on the outer circumferential surface 13o of the intermediate casing 13, 13c that is the shortest distance from the predetermined point. Position A in FIG. 5 is the same position as the groove 16 in the combustor mounting portion 14, and in FIG. 6 is the same position as the groove 16 in FIG. 5 in the combustor mounting portion 14. Position B is the same position as the combustor axis Ab in the radial direction Dr and the rotor axial direction Da in the inter-hole portion 15b of the combustor mounting portion 14. Position C is a position Dro radially outward and Dad axially downstream of the inter-hole portion 15b, and is the position of the boundary between the combustor mounting portion 14 and the combustion liner opposing portion 18, in other words, a position on the inner circumferential surface 14bi of the boundary portion. Here, the maximum stress among the stresses at each position in the thickness direction for each of the multiple positions A, B, and C is defined as the peak stress.

[0049] Furthermore, in FIGS. 5 and 6, a line connecting the peak stresses at each of a plurality of positions in the combustor mounting portion 14 is shown as a peak stress curve Lσmax.

[0050] The width of the inter-hole portion 15b in the combustor mounting portion 14 in the circumferential direction Dc becomes narrower as the number of combustor insertion holes 15, in other words, the number of combustors 30, increases. Furthermore, in recent years, the compression rate of the air in the compressor 20 has been increased in order to improve gas turbine efficiency. In this regard, there is a demand for improving the durability of the intermediate casing 13, 13c having the combustor mounting portion 14 so that it can withstand the increased pressure of the compressed air Acom.

[0051] As described above, during operation of the gas turbine 10, compressed air Acom from the compressor 20 flows into the intermediate casings 13 and 13c. Therefore, during operation of the gas turbine 10, a pressure p of the compressed air Acom is applied to the intermediate casings 13 and 13c, as shown in FIGS. 5 and 6. During operation of the gas turbine 10, the pressure of the air flowing through the compressor casing 24 gradually increases toward the axial downstream side Dad. Therefore, a load acting toward the axial upstream side Dau is applied to the multiple compressor stator vane rows 25 attached to the compressor casing 24. As a result, a force FP acting from the compressor casing 24 toward the axial upstream side Dau is applied to the end 13u of the axial upstream side Dau of the intermediate casings 13 and 13c connected to the compressor casing 24. Furthermore, during operation of the gas turbine 10, the pressure of the combustion gas G flowing through the turbine casing 44 gradually decreases toward the axial downstream side Dad. For this reason, a load acting toward the axial downstream side Dad is applied to the multiple turbine stator vane rows 45 attached to the turbine casing 44. As a result, a force FP acting from the turbine casing 44 toward the axial downstream side Dad is applied to the end 13d of the axial downstream side Dad of the intermediate casings 13, 13c connected to the turbine casing 44. That is, during operation of the gas turbine 10, a force FP acting toward the axial upstream side Dau is applied to the end 13u of the axial upstream side Dau of the intermediate casings 13, 13c, and a force FP acting toward the axial downstream side Dad is applied to the end 13d of the axial downstream side Dad of the intermediate casings 13, 13c. Stresses are generated in the intermediate casings 13, 13c due to these forces FP and the like.

[0052] As shown in Fig. 6 , at the end portion 13u on the axial upstream side Dau of the intermediate casing 13c in the comparative example, the peak stress occurs at approximately the middle position in the thickness direction of the end portion 13u. At Position A of the intermediate casing 13c in the comparative example, the peak stress σac also occurs at approximately the middle position in the thickness direction at Position A. At Position B of the intermediate casing 13c in the comparative example, the peak stress σbc occurs at a position closer to the mounting portion inner circumferential surface 14i than the approximately middle position in the thickness direction at Position B. This peak stress σbc is slightly larger than the peak stress σac at Position A. This is because, while the combustor mounting portion 14 is continuous in the circumferential direction Dc at Position A, Position B is the inter-hole portion 15b, where the combustor mounting portion 14 is divided in the circumferential direction Dc by the two combustor insertion holes 15.

[0053] In the region between positions B and C of the intermediate casing 13c in the comparative example, the position of the peak stress gradually approaches the inner circumferential surface 13i of the intermediate casing 13 as it approaches position C. This is because position C is located within the boundary inner circumferential surface 14bi, and this boundary inner circumferential surface 14bi is a curved surface in which the amount of positional change toward the radially outer side Dro gradually decreases as the positional change toward the axial downstream side Dad. At position C of the intermediate casing 13c in the comparative example, the stress at a position extremely close to the boundary inner circumferential surface 14bi in the thickness direction at this position C becomes the peak stress σcc. As such, when the position of the peak stress σcc is extremely close to the boundary inner circumferential surface 14bi, the stress distribution in the thickness direction at this position C becomes extremely biased toward the boundary inner circumferential surface 14bi. As a result, the peak stress σcc at position C is much larger than the peak stresses σac and σbc at positions A and B.

[0054] In the comparative example, in the region between position C of the intermediate casing 13c and end 13d of the axial downstream side Dad of the intermediate casing 13c, the position of the peak stress gradually moves away from the inner circumferential surface 13i of the intermediate casing 13c as one approaches end 13d. At end 13d of the axial downstream side Dad of the intermediate casing 13c in the comparative example, the peak stress occurs at approximately the middle position in the thickness direction of end 13d.

[0055] As described above, in the intermediate casing 13c of the comparative example, the peak stress σcc at the position C is much larger than the peak stresses at other positions.

[0056] 5, in the present embodiment, at the end 13u on the axial upstream side Dau of the intermediate casing 13, the peak stress occurs at approximately the middle position in the thickness direction of the end 13u, as in the comparative example. Therefore, this peak stress is much smaller than the peak stress σcc at position C of the intermediate casing 13c in the comparative example.

[0057] In the present embodiment, the peak stress σa occurs at approximately the center of the thickness direction at position A on the intermediate casing 13. Therefore, this peak stress σa is much smaller than the peak stress σcc at position C on the intermediate casing 13c in the comparative example. However, this peak stress σa is larger than the peak stress σac at position A on the intermediate casing 13c in the comparative example. This is because the thickness of the intermediate casing 13 in the present embodiment at position A is thinner than the thickness of the intermediate casing 13c in the comparative example at position A due to the presence of the groove 16. Furthermore, as described above, although the position of the peak stress σa is approximately the center of the thickness direction at position A, due to the presence of the groove 16, it is shifted toward the outer peripheral surface 13o of the intermediate casing 13 relative to the position of the peak stress σac in the comparative example.

[0058] In this embodiment, the peak stress σb is also at the position B of the intermediate casing 13, which is approximately the middle position in the thickness direction at this position B. Therefore, this peak stress σb is smaller than the peak stress σbc at the position B of the intermediate casing 13c in the comparative example, and is far smaller than the peak stress σcc at the position C of the intermediate casing 13c in the comparative example.

[0059] In the region between positions A and C of the intermediate casing 13 in this embodiment, the position of the peak stress tends to gradually move closer to the inner circumferential surface 13i of the intermediate casing 13 as it approaches position C. However, by providing the groove 16 at position A of the intermediate casing 13 in this embodiment, the position of the peak stress in the thickness direction within this region is shifted toward the outer circumferential surface 13o of the intermediate casing 13 compared to the comparative example.

[0060] At position C of the intermediate casing 13 in this embodiment, the stress at approximately the middle position in the thickness direction at this position C becomes the peak stress σc. Therefore, this peak stress σc is much smaller than the peak stress σcc at position C of the intermediate casing 13c in the comparative example. Note that, depending on the depth of the groove 16, the position in the thickness direction where the peak stress σc occurs may be slightly closer to the outer peripheral surface 13o of the intermediate casing 13 than the middle position in the thickness direction at position C, or may be slightly closer to the inner peripheral surface 13i (boundary inner peripheral surface 14bi) of the intermediate casing 13 than the middle position in the thickness direction at position C.

[0061] In this embodiment, the peak stress occurs at approximately the middle position in the thickness direction of the end portion 13d on the axial downstream side Dad of the intermediate casing 13. Therefore, this peak stress is much smaller than the peak stress σcc at position C of the intermediate casing 13c in the comparative example.

[0062] As described above, in this embodiment, the peak stress generated at each position in the intermediate casing 13 can be made much smaller than the maximum peak stress σcc among the peak stresses generated at each position in the intermediate casing 13c in the comparative example. Therefore, in this embodiment, the durability of the intermediate casing 13 can be improved while preventing the intermediate casing 13 from becoming larger.

[0063] In the present embodiment, the penetrating direction of the combustor insertion hole 15 is the thickness direction of the combustor mounting portion 14. Therefore, the groove 16 in the present embodiment is recessed in the thickness direction of the combustor mounting portion 14. When the groove 16 is recessed in the thickness direction of the combustor mounting portion 14 in this way, the position where the peak stress occurs in the thickness direction can be easily adjusted by adjusting the amount of recession.

[0064] With regard to shifting the position where peak stress occurs toward the attachment portion outer peripheral surface 14o, the depth of the groove 16 is important, and the width of the groove 16 is basically irrelevant. On the other hand, if the width of the groove 16 in the direction perpendicular to the combustor axis Ab is increased, the width in the direction perpendicular to the combustor axis Ab between the groove bottom and the attachment portion outer peripheral surface 14o also increases, reducing the strength of this portion. For this reason, in the present embodiment, the groove width dimension w is made smaller than the groove depth dimension d.

[0065] In this embodiment, by making the groove depth d of the groove 16 located on the radially inner side Dri relative to the inter-hole portion 15b greater than one-third of the thickness t of the inter-hole portion 15b, the position where peak stress occurs in the thickness direction at the boundary located on the radially outer side Dro relative to the inter-hole portion 15b can be sufficiently shifted toward the outer peripheral surface 13o. On the other hand, if the depth of the groove 16 is made greater than two-thirds of the thickness t of the inter-hole portion 15b, the stress generated between the groove bottom and the mounting portion outer peripheral surface 14o will increase. For this reason, in this embodiment, the groove depth d is made smaller than two-thirds of the thickness t of the inter-hole portion 15b.

[0066] "Variations" The grooves 16 in the above embodiment extend in the circumferential direction Dc in a region of the radially inner side Dri relative to the plurality of combustor insertion holes 15 and the plurality of inter-hole portions 15b, and are annular around the rotor axis line Ar. However, as long as a groove is present in a region of the radially inner side Dri for each of the plurality of inter-hole portions 15b, it is not necessary for the groove to be present in a region of the radially inner side Dri for each of the plurality of combustor insertion holes 15. However, when the grooves 16 are annular around the rotor axis line Ar as in this embodiment, the grooves 16 can be machined continuously. Therefore, in this embodiment, the manufacturing cost and manufacturing time of the intermediate casing 13 can be reduced.

[0067] Furthermore, the present disclosure is not limited to the embodiments described above, and various additions, modifications, substitutions, partial deletions, etc. are possible within the scope of the conceptual idea and spirit of the present invention as derived from the content defined in the claims and their equivalents.

[0068] "Addendum" The gas turbine casing 12 in the above-described embodiment and modified examples can be understood, for example, as follows.

[0069] (1) The gas turbine casing 12 in the first embodiment is a gas turbine casing 12 in which a gas turbine rotor 11 rotatable about a rotor axis Ar is disposed in an internal space. The gas turbine casing 12 includes a combustor mounting portion 14 and a combustion liner opposing portion 18. The combustion liner opposing portion 18 is an end of the combustor mounting portion 14 and is connected to an end of the axial downstream side Dad of an axial upstream side Dau and an axial downstream side Dad in a rotor axial direction Da in which the rotor axis Ar extends. The combustor mounting portion 14 includes a mounting portion outer circumferential surface 14o and a mounting portion inner circumferential surface 14i that is back-to-back with the mounting portion outer circumferential surface 14o and defines an edge of part of the internal space, and the mounting portion inner circumferential surface 14i gradually widens toward the radially outer side Dro of a radially inner side Dri and a radially outer side Dro in the radial direction Dr relative to the rotor axis Ar as it moves toward the axial downstream side Dad. The combustion tube opposing portion 18 has an opposing portion outer peripheral surface 18o that is continuous with the mounting portion outer peripheral surface 14o, and an opposing portion inner peripheral surface 18i that is back-to-back with the opposing portion outer peripheral surface 18o, is continuous with the mounting portion inner peripheral surface 14i, and defines a portion of the internal space that is continuous with the portion of the internal space defined by the mounting portion inner peripheral surface 14i. Among the mounting portion inner peripheral surface 14i and the opposing portion inner peripheral surface 18i, a boundary portion inner peripheral surface 14bi that includes a boundary between the mounting portion inner peripheral surface 14i and the opposing portion inner peripheral surface 18i is a curved surface in which the amount of positional change toward the radially outward side Dro that accompanies a positional change toward the axial downstream side Dad gradually decreases. The combustor mounting portion 14 further includes a plurality of combustor insertion holes 15 that are arranged at intervals in the circumferential direction Dc relative to the rotor axis Ar and that penetrate from the mounting portion outer circumferential surface 14o to the mounting portion inner circumferential surface 14i; inter-hole portions 15b that are between every two combustor insertion holes 15 that are adjacent to each other in the circumferential direction Dc among the plurality of combustor insertion holes 15; and grooves 16 that are recessed from the mounting portion inner circumferential surface 14i toward the mounting portion outer circumferential surface 14o in a region in the circumferential direction Dc where the inter-hole portions 15b are present, the region being radially inward Dri in the radial direction Dr than the inter-hole portions 15b.

[0070] During operation of the gas turbine 10, the gas turbine casing 12 generates stresses specific to this operation. The direction of extension of the combustor mounting portion 14 differs from the direction of extension of the combustion liner facing portion 18 connected to the axial downstream end (Dad) of the combustor mounting portion 14. The boundary inner circumferential surface 14bi, which includes the boundary between the mounting portion inner circumferential surface 14i and the facing portion inner circumferential surface 18i, is a curved surface in which the amount of positional change toward the radially outer side (Dro) gradually decreases with the change toward the axial downstream end (Dad). In this case, the peak stress σcc, which is the maximum stress among the stresses at each position in the thickness direction at the boundary between the combustor mounting portion 14 and the combustion liner facing portion 18, tends to occur closer to the boundary inner circumferential surface 14bi. If the position of this peak stress σcc were to be significantly closer to the boundary inner circumferential surface 14bi, the stress distribution in the thickness direction at this boundary would be significantly biased toward the boundary inner circumferential surface 14bi. As a result, the peak stress σcc at the boundary would be significantly increased.

[0071] The gas turbine casing 12 in this embodiment has a groove 16 recessed from the attachment portion inner circumferential surface 14i toward the attachment portion outer circumferential surface 14o in a region Dri radially inward of the inter-hole portion 15b. With this groove 16, the position at which peak stress occurs in the thickness direction in a region Dro radially outward of the groove 16 shifts toward the attachment portion outer circumferential surface 14o compared to when the groove 16 is not present. In this relationship, the peak stress σc in the thickness direction at the boundary also shifts toward the attachment portion outer circumferential surface 14o, and the stress distribution in the thickness direction at the boundary is more averaged than when the groove 16 is not present. Therefore, in this embodiment, the magnitude of the peak stress σc in the thickness direction at the boundary can be suppressed.

[0072] Therefore, in this embodiment, the durability of the gas turbine casing 12 can be improved while preventing the gas turbine casing 12 from becoming larger.

[0073] (2) The gas turbine casing 12 in the second embodiment is In the gas turbine casing 12 according to the first aspect, the penetration direction of the plurality of combustor insertion holes 15 is a combustor axial direction Db in which the combustor axis Ab extends. The combustor axis Ab is inclined with respect to the rotor axis Ar so as to gradually approach the rotor axis Ar toward the axial downstream side Dad. The grooves 16 are recessed in the combustor axial direction Db.

[0074] When a through hole is formed in a plate, the penetration direction of the through hole is generally perpendicular to the plate, in other words, the penetration direction is the thickness direction of the plate. If the penetration direction of the combustor insertion hole 15 is the thickness direction of the combustor mounting portion 14, in this embodiment, the groove 16 is recessed in the thickness direction of the combustor mounting portion 14. When the groove 16 is recessed in the thickness direction of the combustor mounting portion 14 in this way, the position where peak stress occurs in the thickness direction can be easily adjusted by adjusting the amount of recession.

[0075] (3) The gas turbine casing 12 in the third aspect is In the gas turbine casing 12 according to the second aspect, a groove width dimension w of the grooves 16 in a direction having a directional component of the radial direction Dr and perpendicular to the combustor axis Ab is smaller than a groove depth dimension d of the grooves 16 in the combustor axis direction Db.

[0076] With regard to shifting the position where peak stress occurs toward the attachment portion outer peripheral surface 14o, the depth of the groove 16 is important, and the width of the groove 16 is basically irrelevant. On the other hand, if the width of the groove 16 in the direction perpendicular to the combustor axis Ab is increased, the width in the direction perpendicular to the combustor axis Ab between the groove bottom and the attachment portion outer peripheral surface 14o also increases, reducing the strength of this portion. For this reason, in this aspect, the groove width dimension w is made smaller than the groove depth dimension d.

[0077] (4) The gas turbine casing 12 in the fourth aspect is In the gas turbine casing 12 according to the second aspect or the third aspect, a groove depth dimension d of the grooves 16 in the combustor axial direction Db is greater than 1 / 3 of the thickness t of the inter-hole portion 15b in the combustor axial direction Db and is smaller than 2 / 3 of the thickness t of the inter-hole portion 15b in the combustor axial direction Db.

[0078] By making the groove depth d of the groove 16 located on the radially inner side Dri with respect to the inter-hole portion 15b greater than one-third of the thickness t of the inter-hole portion 15b, the position where peak stress occurs in the thickness direction at the boundary located on the radially outer side Dro with respect to the inter-hole portion 15b can be sufficiently shifted toward the outer peripheral surface 13o. On the other hand, if the depth of the groove 16 is made two-thirds or more of the thickness t of the inter-hole portion 15b, the stress generated between the groove bottom and the mounting portion outer peripheral surface 14o will increase. For this reason, in this embodiment, the groove depth d is made greater than one-third of the thickness t of the inter-hole portion 15b but less than two-thirds of the thickness t of the inter-hole portion 15b.

[0079] (5) The gas turbine casing 12 in the fifth aspect is In the gas turbine casing 12 according to any one of the first to fourth aspects, the groove 16 extends in the circumferential direction Dc and is annular around the rotor axis line Ar.

[0080] When the groove 16 is formed in an annular shape around the rotor axis Ar as in this embodiment, it is possible to continuously process the groove 16. Therefore, in this embodiment, the manufacturing cost and manufacturing time of the gas turbine casing 12 can be reduced.

[0081] (6) The gas turbine casing 12 in the sixth aspect is In the gas turbine casing (12) according to any one of the first to fifth aspects, the combustor mounting portion (14) includes a stationary component mounting portion (17) at a portion radially inward Dri than the groove (16). The stationary component is mounted within the internal space and is disposed radially inward Dri than the plurality of combustor insertion holes (15).

[0082] In this embodiment, stationary components can be easily disposed radially inward Dri of the plurality of combustor insertion holes 15.

[0083] The gas turbine 10 in the above-described embodiment and modified examples can be understood, for example, as follows. (7) In a seventh aspect, the gas turbine 10 includes: The gas turbine includes: the gas turbine casing (12) according to any one of claims 1 to 6 in any one of the first to sixth aspects; the gas turbine rotor (11); and a combustor (30) having a portion inserted into each of the plurality of combustor insertion holes (15) and fixed to the combustor mounting portion (14). [Explanation of symbols]

[0084] 1: Cooling air supply device 2: Bleed line 3: Cooler 4: Cooling air line 5: Boost compressor 9: Generator 10: Gas turbine 11: Gas turbine rotor 11s: Gas turbine rotor shaft 11m: Intermediate rotor shaft 12: Gas turbine casing 13, 13c: Intermediate casing 13i: Inner surface 13o: Outer surface 13u: Axis upstream end 13d: Downstream end of axis 14: Combustor mounting part 14i: Inner surface of mounting part 14o: Outer surface of mounting part 14bi: Boundary inner surface 15: Combustor insertion hole 15b: Hole area 16: Groove 17: Stationary parts mounting part 17a: First mounting part 17b: Second mounting part 18: Combustion cylinder facing part 18i: Inner surface of opposing part 18o: Outer surface of opposing part 19: Exhaust casing 20: Compressor 21: Compressor rotor 22: Compressor rotor shaft 23: Compressor rotor blade row 24: Compressor casing 25: Compressor stator blade row 26: Diffuser 26i: Inner diffuser 26o: Outer diffuser 27: Cooling air jacket 28: Diffuser support leg (stationary part) 30: Combustor 32: Combustion tube (or tail tube) 34: Nozzle base 35: Mounting flange 39: Cylinder support leg (stationary part) 40: Turbine 41: Turbine rotor 42: Turbine rotor shaft 43: Turbine blade row 44: Turbine casing 45: Turbine stator blade row 49: Combustion gas flow path 50: Intermediate shaft cover 51: Cover body 52: Strut A: Air Acom: Compressed air Acl: Cooling air F:Fuel G: Combustion gas EG: Exhaust gas Ar: rotor axis Ab: Combustor axis Da: Rotor axial direction Dau: Axis upstream side Dad: Downstream of the axis Dc: Circumferential direction Dr: Radial direction Dri: Radial inner direction Dro: Radial outer side Db: Combustor axial direction Dbb: proximal side Dbt: ​​Tip side Lσmax: Peak stress curve FP: Power

Claims

1. A gas turbine casing having an internal space in which a gas turbine rotor rotatable about a rotor axis is disposed, a combustor mounting portion and a combustion liner opposing portion, the combustion liner opposing portion is an end of the combustor mounting portion, and is connected to an end on the axial downstream side of an axial upstream side and an axial downstream side in a rotor axial direction in which the rotor axis extends, the combustor mounting portion includes an mounting portion outer circumferential surface and an mounting portion inner circumferential surface that is back-to-back with the mounting portion outer circumferential surface and defines an edge of a portion of the internal space, the mounting portion inner circumferential surface gradually widening toward the radially outer side as it extends downstream along the axis, the combustion tube opposing portion has an opposing portion outer peripheral surface that is continuous with the mounting portion outer peripheral surface, and an opposing portion inner peripheral surface that is back-to-back with the opposing portion outer peripheral surface, is continuous with the mounting portion inner peripheral surface, and defines a portion of the internal space that is continuous with the portion of the internal space defined by the mounting portion inner peripheral surface, a boundary portion inner circumferential surface including a boundary between the mounting portion inner circumferential surface and the opposing portion inner circumferential surface is a curved surface in which an amount of positional change toward the radially outward side that accompanies a positional change toward the axial downstream side gradually decreases, The combustor mounting portion further comprises: a plurality of combustor insertion holes that are arranged at intervals in a circumferential direction relative to the rotor axis and that penetrate from an outer peripheral surface of the mounting portion to an inner peripheral surface of the mounting portion; an inter-hole portion between every two combustor insertion holes adjacent to each other in the circumferential direction among the plurality of combustor insertion holes; a groove recessed from the inner peripheral surface of the mounting portion toward the outer peripheral surface of the mounting portion in a circumferential region where the inter-hole portion is present and which is located radially inward of the inter-hole portion in the radial direction; having Gas turbine casing.

2. 2. The gas turbine casing according to claim 1, a penetration direction of each of the plurality of combustor insertion holes is a combustor axial direction in which the combustor axis extends and is inclined with respect to the rotor axis to gradually approach the rotor axis toward a downstream side of the axis, the groove is recessed in the combustor axial direction. Gas turbine casing.

3. 3. The gas turbine casing according to claim 2, a groove width dimension of the groove in a direction having a radial component and perpendicular to the combustor axis is smaller than a groove depth dimension of the groove in the combustor axis direction; Gas turbine casing.

4. 3. The gas turbine casing according to claim 2, a groove depth dimension of the groove in the combustor axial direction is greater than one-third of a thickness of the inter-hole portion in the combustor axial direction and is smaller than two-thirds of the thickness of the inter-hole portion in the combustor axial direction. Gas turbine casing.

5. 2. The gas turbine casing according to claim 1, The groove extends in the circumferential direction and is annular around the rotor axis. Gas turbine casing.

6. 2. The gas turbine casing according to claim 1, the combustor mounting portion includes a stationary component mounting portion, at a portion radially inward of the groove, to which a stationary component disposed within the internal space and radially inward of the plurality of combustor insertion holes is mounted. Gas turbine casing.

7. A gas turbine casing according to any one of claims 1 to 6; the gas turbine rotor; a combustor partially inserted into each of the plurality of combustor insertion holes and fixed to the combustor mounting portion; A gas turbine comprising:

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