Gas turbines and combustors

Abstract

A gas turbine and a combustor that can improve operability and performance are provided. [Solution] The combustor has an outer cylinder that extends around the combustor axis and has a tip that protrudes further into the casing than the insertion hole, and an inner cylinder that forms an annular introduction flow path that opens toward the insertion direction of the combustor between the outer cylinder and the inner cylinder, a first bell mouth that is provided so as to rise in the insertion direction from the peripheral edge of the insertion hole on the inner surface of the casing and extends over a first circumferential range that is part of the circumferential range of the combustor axis and has a first guide surface that guides air to the introduction flow path, a second bell mouth that is provided at the tip of the outer cylinder and extends over a second circumferential range excluding the first circumferential range of the circumferential range and has a second guide surface that guides air to the introduction flow path, and the first guide surface and the second guide surface are connected to each other in the circumferential direction to form an annular guide surface.

Description

[Technical Field]

[0001] The present disclosure relates to gas turbines and combustors. [Background technology]

[0002] The casing of the gas turbine has an insertion hole that penetrates the inside and outside of the casing. A combustor is inserted into the insertion hole from the outside of the casing. The combustor has an outer cylinder and an inner cylinder that is coaxially arranged inside the outer cylinder. An annular introduction flow passage that opens in the insertion direction of the combustor is formed between the outer cylinder and the inner cylinder.

[0003] The following Patent Document discloses a configuration in which a bell mouth, a flow guide, etc. are provided at the tip of the outer cylinder in order to allow air to smoothly flow into the inlet flow path of the combustor. Patent Document 1 discloses a gas turbine in which a bell mouth is attached to the entire outer periphery of the inlet flow passage. Patent Document 2 discloses a gas turbine in which a flow guide is provided on a portion of the circumferential direction of the outer periphery of an inlet flow passage, and a portion of the circumferential direction of an insertion hole of a casing into which a combustor is inserted is formed into a convex curved surface. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-346361 [Patent Document 2] Patent Publication No. 2021-148099 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, the gas turbine described in Patent Document 1 requires the installation of a flow guide around the entire circumference of the insertion hole in the narrow space inside the casing, which poses a problem of cumbersome installation work. Meanwhile, in recent years, gas turbines have been developed in which the outer cylinder protrudes further into the casing than the insertion hole of the combustor. When the technology described in Patent Document 2 is applied to such gas turbines, the convex curved surface of the casing does not function as a flow guide or bell mouth. Therefore, there is a problem in that smooth air inflow cannot be achieved.

[0006] The present disclosure has been made to solve the above-mentioned problems, and has an object to provide a gas turbine and a combustor that can further improve operability and performance. [Means for solving the problem]

[0007] a first bell mouth provided at the tip of the external cylinder, extending over a first circumferential range that is a partial area around the axis in the circumferential direction of the axis, the first bell mouth having a first guide surface that guides air to the introduction passage; a second bell mouth provided at the inner surface of the casing so as to rise in the insertion direction from a peripheral edge of the insertion hole, the second bell mouth extending over a second circumferential range that is a partial area around the axis in the circumferential direction excluding the first circumferential range, the second bell mouth having a second guide surface that guides air to the introduction passage; and a second bell mouth provided at the inner surface of the casing so as to rise in the insertion direction from a peripheral edge of the insertion hole, the second bell mouth extending over a second circumferential range that is a partial area around the axis in the circumferential direction excluding the first circumferential range, the second bell mouth having a second guide surface that guides air to the introduction passage.

[0008] A combustor according to the present disclosure comprises: an external cylinder that extends about a combustor axis and has an insertion hole penetrating from an inside to an outside of the casing, with a tip that protrudes into the casing beyond the insertion hole; an inner cylinder that is disposed inside the external cylinder and forms, between the external cylinder and the inner cylinder, an annular introduction flow path that opens toward an insertion direction that is a direction in which the external cylinder is inserted into the casing; a first bell mouth that is provided on an inner surface of the casing to rise from a peripheral edge of the insertion hole in the insertion direction, the first bell mouth extending over a first circumferential range that is a part of the circumferential range of the combustor axis, the first bell mouth having a first guide surface that guides air to the introduction flow path; and a second bell mouth that is provided at the tip of the external cylinder and extending over a second circumferential range within the circumferential range excluding the first circumferential range, the second bell mouth having a second guide surface that guides air to the introduction flow path, wherein the first guide surface and the second guide surface are connected to each other in the circumferential direction to form an annular guide surface. [Effects of the Invention]

[0009] The gas turbine and combustor of the present disclosure can improve operability and performance. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a configuration of a gas turbine according to a first embodiment of the present disclosure. [Figure 2] 1 is a cross-sectional view including a rotor axis of a gas turbine according to a first embodiment of the present disclosure, and is a partially enlarged view showing a combustor and its surrounding configuration. FIG. [Figure 3] FIG. 2 is a view of an insertion hole in a casing of the gas turbine according to the first embodiment of the present disclosure, as viewed from the insertion direction of the combustor. [Figure 4] This is a cross-sectional view taken along the line IV-IV in Figure 2. Note that the configuration inside the inner cylinder is not shown. [Figure 5] FIG. 2 is a perspective view showing the positional relationship between a first bell mouth and a second bell mouth in the combustor of the gas turbine according to the first embodiment of the present disclosure. [Figure 6]FIG. 3 is a partially enlarged view of the vicinity of the first bell mouth in FIG. 2. [Figure 7] FIG. 2 is a perspective view of an outer casing unit and an acoustic damper in the combustor of the gas turbine according to the first embodiment of the present disclosure. [Figure 8] FIG. 3 is a partially enlarged view of the vicinity of the second bell mouth and the acoustic damper in FIG. 2. [Figure 9] FIG. 4 is a cross-sectional view including a rotor axis of a gas turbine according to a second embodiment of the present disclosure, and is a partially enlarged view showing a combustor and its surrounding structure. [Figure 10] FIG. 10 is a perspective view showing a first bell mouth and a second bell mouth in a combustor of a gas turbine according to a second embodiment of the present disclosure. [Figure 11] FIG. 10 is a partially enlarged view of the vicinity of the first bell mouth in FIG. [Figure 12] 11 is a cross-sectional view of FIG. 10 taken along line B-B. DETAILED DESCRIPTION OF THE INVENTION

[0011] First Embodiment <Overall configuration of gas turbine> A gas turbine 1 according to a first embodiment of the present invention will be described below with reference to the drawings. 1, the gas turbine 1 includes a compressor 2, a turbine 10, an intermediate casing 20, and a combustor 30. As shown in FIGS. 2 and 4, the gas turbine 1 further includes a first bell mouth 90, a second bell mouth 50, and an acoustic damper 80.

[0012] <Compressor> The compressor 2 generates high-pressure air. The compressor 2 has a compressor rotor 3 that rotates about a rotor axis A, and a compressor casing 4 that surrounds the compressor rotor 3 from its outer periphery (radially outside the rotor axis A). A plurality of compressor rotor blade stages 5 are provided on the outer periphery of the compressor rotor 3 and arranged at intervals in the direction of the rotor axis A. Each compressor rotor blade stage 5 is made up of a plurality of compressor rotor blades that are arranged at intervals in the circumferential direction of the axis on the outer periphery of the compressor rotor 3.

[0013] The compressor casing 4 has a cylindrical shape centered on the rotor axis A. A plurality of compressor stator vane stages 6 are provided on the inner peripheral surface of the compressor casing 4 and arranged at intervals in the axial direction. The plurality of compressor stator vane stages 6 are arranged alternately with the plurality of compressor rotor blade stages 5 when viewed from the direction of the rotor axis A. Each compressor stator vane stage 6 is made up of a plurality of compressor stator vanes arranged at intervals in the circumferential direction of the rotor axis A on the inner peripheral surface of the compressor casing 4.

[0014] <Turbine> The turbine 10 is driven by the combustion gas. The turbine 10 is provided on one side of the compressor 2 in the direction of the rotor axis A (the right side in FIG. 1 ). The turbine 10 has a turbine rotor 11 that rotates about the rotor axis A, and a turbine casing 12 that surrounds the turbine rotor 11 from its outer periphery (the radially outer side of the rotor axis A). A plurality of turbine rotor blade stages 13 are provided on the outer periphery of the turbine rotor 11 and arranged at intervals in the direction of the rotor axis A. Each turbine rotor blade stage 13 is made up of a plurality of turbine 10 rotor blades that are arranged at intervals in the circumferential direction of the rotor axis A on the outer periphery of the turbine rotor 11. The turbine rotor 11 is connected to the compressor rotor 3 in the direction of the rotor axis A. The compressor rotor 3 and the turbine rotor 11 connected in this manner constitute a gas turbine rotor 15.

[0015] The turbine casing 12 has a cylindrical shape centered on the rotor axis A. A plurality of turbine stator vane stages 14 are arranged at intervals in the direction of the rotor axis A on the inner peripheral surface of the turbine casing 12. The plurality of turbine stator vane stages 14 are arranged alternately in the direction of the rotor axis A with respect to the plurality of turbine rotor blade stages 13. Each turbine stator vane stage 14 is made up of a plurality of turbine stator vanes arranged at intervals in the circumferential direction of the rotor axis A on the inner peripheral surface of the turbine casing 12.

[0016] <Intermediate casing> The intermediate casing 20 is disposed between the compressor casing 4 and the turbine casing 12 in the direction of the rotor axis A. The intermediate casing 20 has a cylindrical shape centered on the rotor axis A. The intermediate casing 20 covers the gas turbine rotor 15 from the outer periphery side. Compressed air generated by the compressor 2 flows into the internal space of this intermediate casing 20. The compressor casing 4, the intermediate casing 20, and the turbine casing 12 form a gas turbine casing 25.

[0017] <Insertion hole> As shown in FIG. 2, an intermediate casing 20 which is a part of a gas turbine casing 25 has an insertion hole 22 formed therein which penetrates the intermediate casing 20 from the inside to the outside. A plurality of insertion holes 22 are formed at intervals around the rotor axis A. The insertion holes 22 extend in a direction inclined with respect to the rotor axis A so as to move radially inward from the rotor axis A toward the turbine 10 side, which is one side in the direction of the rotor axis A. The insertion holes 22 have a uniform shape in the extending direction.

[0018] The combustor 30 is attached by being inserted into the insertion hole 22 from the outside of the intermediate casing 20 in the extending direction of the insertion hole 22. Hereinafter, the direction in which the combustor 30 is inserted into the insertion hole 22 (the extending direction of the insertion hole 22 toward the inside of the intermediate casing 20) will be simply referred to as the "insertion direction D1." The combustor 30 is removed by pulling it out in the opposite direction to the insertion direction D1 with respect to the insertion hole 22. Hereinafter, the direction in which the combustor 30 is removed (the direction toward the outside of the intermediate casing 20 among the extending directions of the insertion hole 22) will be simply referred to as the "removal direction D2."

[0019] The insertion direction D1 and the extraction direction D2 coincide with the direction to which the combustor axis O, which is the central axis of the combustor 30 when attached to the insertion hole 22, extends. That is, the combustor axis O extends radially inward from the rotor axis A as it extends toward one side in the direction of the rotor axis A.

[0020] 3, the insertion hole 22, as viewed from the insertion direction D1, has an elongated hole shape extending with its longitudinal direction being the radial direction of the rotor axis A. The insertion hole 22 is composed of two spaces, a first space M and a second space E. The first space M is a space whose contour is defined by an imaginary circle C that is a perfect circle centered on the axis when viewed from the insertion direction D1. That is, the first space M has a circular hole shape whose cross section perpendicular to the combustor axis O coincides with the imaginary circle C.

[0021] Here, within the circumferential range of the imaginary circle C, an angular range located radially inward from the rotor axis A is defined as a first circumferential range θ1. The remaining angular range excluding the first circumferential range θ1 is defined as a second circumferential range θ2. The second circumferential range θ2 is an angular range located radially outward from the rotor axis A. When viewed from the insertion direction D1, the first circumferential range θ1 and the second circumferential range θ2 are line-symmetric with respect to a reference line L that extends in the radial direction of the rotor shaft and passes through the combustor axis O. The angle of the first circumferential range θ1 is larger than the angle of the second circumferential range θ2.

[0022] The second space E is a space formed by the first space M bulging outward in the radial direction with respect to the combustor axis O. The second space E is formed by a portion of a second circumferential range θ2 of an imaginary circle C defining the outline of the first space M expanding outward in the radial direction with respect to the rotor axis A.

[0023] The inner circumferential surface of the insertion hole 22 is composed of a first inner circumferential surface 23 and a second inner circumferential surface 24. The first inner circumferential surface 23 defines a first circumferential range θ1 in the outline of the first space M as viewed from the insertion direction D1. The second inner circumferential surface 24 defines the outline of the second space E as viewed from the insertion direction D1. The second inner circumferential surface 24 is formed to bulge from the first inner circumferential surface 23 toward the rotor axis A.

[0024] The second inner peripheral surface 24 is constituted by a pair of opposing inner peripheral surfaces 24a of the rotor and a cylindrical inner peripheral surface 24b. The pair of opposing inner circumferential surfaces 24a extend from both circumferential ends of the first inner circumferential surface 23 toward the radially outer side of the rotor shaft and so as to face each other when viewed from the insertion direction D1. When viewed from the insertion direction D1, the cylindrical inner circumferential surface 24b connects the radially outer ends of the pair of opposing inner circumferential surfaces 24a of the rotor shaft and has an arc shape that convex outward in the radial direction of the rotor shaft. The center of the radius of curvature of the cylindrical inner circumferential surface 24b is located on the reference line L and radially outward of the rotor shaft than the combustor axis O.

[0025] <Combustor> The combustor 30 generates combustion gas by mixing fuel with high-pressure air and burning the mixture. As shown in Fig. 2, the combustor 30 includes an outer casing 41, a mounting flange 42, an end cover 60, an inner casing 70, a combustion casing 72, various nozzles, and various fuel ports.

[0026] <Outer barrel> The external cylinder 41 has a cylindrical shape centered on the combustor axis O and extending in the combustor axis O direction. The outer diameter of the external cylinder 41 corresponds to the diameters of the imaginary circle C and the first inner circumferential surface 23. The outer diameter of the external cylinder 41 may be the same as or slightly smaller than the diameters of the imaginary circle C and the first inner circumferential surface 23. The dimension of the external cylinder 41 in the combustor axis O direction is larger than the dimension of the insertion hole 22 in the combustor axis O direction. The external cylinder 41 is disposed in the first space M of the insertion hole 22. A tip of the external cylinder 41, which is the end of the external cylinder 41 in the insertion direction D1, protrudes further inwardly of the intermediate casing 20 than the insertion hole 22. That is, the tip of the external cylinder 41 protrudes further in the insertion direction D1 (to one side in the direction of the combustor axis O) than a peripheral edge of the insertion hole 22 on the inner surface 21 of the intermediate casing 20.

[0027] <Mounting flange> The mounting flange 42 is provided integrally with the rear end, which is the end of the external casing 41 in the extraction direction D2 (the other side in the direction of the combustor axis O). The mounting flange 42 is provided to protrude from the end of the external casing 41 radially outwardly about the combustor axis O over the entire periphery. A surface of the mounting flange 42 facing the insertion direction D1 abuts over the entire periphery against a circumferential edge portion of the insertion hole 22 in the outer surface of the intermediate casing 20. Flange bolts 42a that penetrate the mounting flange 42 in the thickness direction are provided at multiple locations on the mounting flange 42 in the circumferential direction of the combustor axis O. The mounting flange 42 is detachably fixed to the intermediate casing 20 by fastening the multiple flange bolts 42a to the intermediate casing 20.

[0028] <End cover> The end cover 60 has a disk shape centered on the combustor axis O. The end cover 60 is disposed in the space within the external casing 41 near the center of the external casing 41 in the direction of the combustor axis O. The end cover 60 divides the space within the external casing 41 into two sections in the direction of the combustor axis O.

[0029] <Inner cylinder> The inner cylinder 70 has a cylindrical shape centered on the combustor axis O and extending in the direction of the combustor axis O. The outer diameter of the inner cylinder 70 is smaller than that of the outer cylinder 41. The inner cylinder 70 is disposed inside the outer cylinder 41 and coaxially with the outer cylinder 41. A tip, which is the end of the inner cylinder 70 on the insertion direction D1 side, protrudes beyond the outer cylinder 41 in the insertion direction D1. The inner cylinder 70 is fixed to an inner circumferential surface of the outer cylinder 41 via a plurality of struts 71 that are disposed at intervals in the circumferential direction of the combustor axis O.

[0030] As described above, the inner cylinder 70 is coaxially disposed inside the outer cylinder 41, and thus an annular introduction flow path F is defined and formed between the inner cylinder 70 and the outer cylinder 41 around the combustor axis O. The introduction flow path F opens in the insertion direction D1. The introduction flow path F is in communication with the internal space of the intermediate casing 20. Air is introduced into the introduction flow path F from the entire circumferential direction of the combustor axis O via the introduction flow path F. The air flowing through the introduction flow path F in the extraction direction D2 turns around at the rear end of the inner cylinder 70 inside the outer cylinder 41, enters the inner cylinder 70, and travels inside the inner cylinder 70 in the insertion direction D1.

[0031] <Combustion tube> The combustion liner 72 is a cylindrical member. The portion of the combustion liner 72 on the extraction direction D2 side has a cylindrical shape centered on the combustor axis O, and is connected to the inner liner 70 so as to cover the portion of the inner liner 70 on the insertion direction D1 side from the outer periphery. The end of the combustion liner 72 on the insertion direction D1 side is bent in a direction along the rotor axis A and connected to the turbine 10.

[0032] <Various nozzles> The combustor 30 has various nozzles, including a pilot nozzle 73, a main nozzle 74, and a top hat nozzle 75. The pilot nozzle 73 extends from the end plate in the insertion direction D1 along the combustor axis O. A plurality of main nozzles 74 are provided at intervals around the pilot nozzle 73, and extend from the end plate in the insertion direction D1 parallel to the pilot nozzle 73. The tips of the pilot nozzle 73 and the main nozzle 74 are located inside the inner cylinder 70. The pilot nozzle 73 and the main nozzle 74 are capable of injecting fuel inside the inner cylinder 70.

[0033] The top hat nozzles 75 are provided in plurality on the inner surface 21 of the external casing 41 on side closer to the insertion direction D1 than the end plate, while being spaced apart in the circumferential direction of the combustor axis O. The top hat nozzles 75 inject fuel into air that reverses its direction inside the external casing 41.

[0034] <Various fuel ports> The combustor 30 has various fuel ports, including a pilot port 76, a main port 77, and a top hat port 78. The pilot port 76 and the main port 77 are provided to extend from the end plate in the discharge direction D2. Fuel to be supplied to the pilot nozzle 73 is supplied from the outside to the pilot port 76. Fuel to be supplied to the multiple main nozzles 74 is supplied from the outside to the main port 77.

[0035] One end of the top hat port 78 is connected to a portion of the outer circumferential surface 41 a of the external casing 41 in the vicinity of an installation position of the end plate. The top hat port 78 extends in the second space E of the insertion hole 22 in the extraction direction D2 and penetrates the mounting flange 42 in the direction of the combustor axis O. Fuel to be supplied to the multiple top hat nozzles 75 is supplied from the outside to the top hat port 78.

[0036] <First Bellmouth> As shown in FIGS. 2 and 4 to 6 , the first bell mouth 90 is detachably fixed to a peripheral portion of the insertion hole 22 on the inner surface 21 of the intermediate casing 20. The first bell mouth 90 is provided so as to rise from the peripheral portion in the insertion direction D1. As shown in FIG. 4 , the first bell mouth 90 extends over a first circumferential range θ1 at the peripheral portion of the insertion hole 22. As viewed from the insertion direction D1, a radially inner edge portion of the first bell mouth 90 extends in the circumferential direction about the combustor axis O along the opening edge portion of the first inner circumferential surface 23 of the insertion hole 22, i.e., the first circumferential range θ1 of the imaginary circle C. As viewed from the insertion direction D1, a pair of first end faces 90a located at both circumferential ends of the first bell mouth 90 are provided so as to overlap a pair of opposing inner circumferential surfaces 24a of the second inner circumferential surface 24 of the insertion hole 22. As shown in FIGS. 5 and 6, the first bell mouth 90 has an attachment portion 91, a first extension portion 92, and a first lip 93.

[0037] <Mounting part> The mounting portion 91 has a plate shape with its thickness direction aligned with the insertion direction D1 and extends over the entire first circumferential range θ1. The surface of the mounting portion 91 facing the removal direction D2 abuts against the peripheral edge of the insertion hole 22 on the inner surface 21 of the intermediate casing 20. The mounting portion 91 is detachably fixed to the intermediate casing 20 by fastening bolts 91a that penetrate the mounting portion 91 from the insertion direction D1 side toward the removal direction D2 side to the inner surface 21 of the intermediate casing 20. A plurality of bolts 91a are provided at intervals in the circumferential direction over the first circumferential range θ1.

[0038] <First extension section> The first extending portion 92 is provided to rise from the entire circumferential direction of a radially inner edge of the mounting portion 91, i.e., from the entire first circumferential range θ1, in the insertion direction D1. The first extending portion 92 has a plate shape extending in an arc shape over the first circumferential range θ1 with its thickness direction aligned with the radial direction of the combustor axis O. The first extending portion 92 protrudes in the insertion direction D1 beyond a tip of the external cylinder 41. An inner circumferential surface 92a of the first extending portion 92 facing radially inward has a cylindrical surface shape centered on the combustor axis O. When viewed from the insertion direction D1, the inner circumferential surface 92a of the first extending portion 92 coincides with an imaginary circle C or is located on the outer circumferential side of the imaginary circle C across a small gap. The inner circumferential surface 92a is in abutment with the outer circumferential surface 41a of the external cylinder 41 over the entire first circumferential range θ1 or faces the outer circumferential surface 41a of the external cylinder 41 across a small gap.

[0039] <First Lip> The first lip 93 is provided to spread radially outward from the combustor axis O over a first circumferential range θ1 from a tip of the first extension portion 92 in the insertion direction D1. A first guide surface 93a is formed at a portion of the first lip 93 facing radially inward. The first guide surface 93a is configured to guide air toward the introduction flow path F. The first guide surface 93a has a convex curved shape that decreases in diameter toward the extraction direction D2 that is the direction of introduction of air into the introduction flow path F. The first guide surface 93a has a convex curved shape that extends in a curved manner to spread radially outward from the combustor axis O toward the insertion direction D1. The first guide surface 93a is smoothly connected to an inner circumferential surface 92a of the first extension portion 92.

[0040] <Second bell mouth> As shown in Figures 2, 4, and 5 to 8, the first bell mouth 90 is provided integrally with the tip of the outer cylinder 41. The second bell mouth 50 is provided integrally with the outer cylinder 41 by, for example, being welded to the tip of the outer cylinder 41. The second bell mouth 50 may also be molded integrally with the outer cylinder 41. The outer cylinder 41, the mounting flange 42 and the second bell mouth 50 constitute an outer cylinder unit 40 having a paired structure.

[0041] As shown in Fig. 4, the second bell mouth 50 extends over a first circumferential range θ1 at the tip of the outer cylinder 41. When viewed from the insertion direction D1, the radially inner edge of the second bell mouth 50 extends along a second circumferential range θ2 of the imaginary circle C. When viewed from the insertion direction D1, a pair of second end faces 50a located at both circumferential ends of the second bell mouth 50 are arranged inside, in the opposing direction, the pair of opposing inner circumferential surfaces 24a of the second inner circumferential surface 24 in the insertion hole 22. When viewed from the insertion direction D1, the pair of second end faces 50a of the second bell mouth 50 are arranged with a small gap between them and the corresponding opposing inner circumferential surfaces 24a. As shown in FIGS. 5 to 8, the second bell mouth 50 has a second extension portion 52 and a second lip 53.

[0042] <Second extension section> The second extension portion 52 has a plate shape with its thickness direction aligned with the radial direction of the combustor axis O and extending in an arc shape over a second circumferential range θ2. As shown in FIGS. 7 and 8 , an inner circumferential surface 52a of the second extension portion 52 on the extraction direction D2 side is integrally fixed to an outer circumferential surface 41a of the external cylinder 41. A portion of the second extension portion 52 on the insertion direction D1 side protrudes in the insertion direction D1 beyond the tip of the external cylinder 41. As seen in the insertion direction D1, the inner circumferential surface 52a of the second extension portion 52 coincides with an imaginary circle C or is located on the outer circumferential side of the imaginary circle C with a slight gap therebetween. An outer circumferential surface 52b of the second extension portion 52 has a cylindrical surface shape centered on the combustor axis O.

[0043] <Second Lip> The second lip 53 is provided to spread radially outward from the combustor axis O over a second circumferential range θ2 from a tip of the second extension portion 52 in the insertion direction D1. A second guide surface 53a is formed at a portion of the second lip 53 facing radially inward. The second guide surface 53a is configured to guide air toward the introduction flow path F. The second guide surface 53a has a convex curved shape that decreases in diameter as the second guide surface 53a proceeds in the extraction direction D2, which is the direction in which air is introduced into the introduction flow path F. The second guide surface 53a has a convex curved shape that curves and extends to spread radially outward from the combustor axis O as the second guide surface 53a proceeds in the insertion direction D1. The second guide surface 53a is smoothly connected to an inner circumferential surface 52a of the second extension portion 52. The surface of the second lip 53 facing the extraction direction D2 is a second lip back surface 53b. A space is formed between the second lip back surface 53b and the outer peripheral surface 52b of the second extension portion 52.

[0044] <Annular guide surface 100a, annular bell mouth 100> 4 and 5, the pair of first end faces 90a of the first bell mouth 90 face each other with a small gap between them at the boundary between the first circumferential range θ1 and the second circumferential range θ2. The shapes of the tip ends of the first end face 90a and the second end face 50a on the insertion direction D1 side are the same. The first end face 90a and the second end face 50a face each other in the circumferential direction with corresponding shapes, and the first bell mouth 90 and the second bell mouth 50 are connected to each other in the circumferential direction with a small gap between them.

[0045] The first guide surface 93a of the first bell mouth 90 and the second guide surface 53a of the second bell mouth 50 are smoothly connected via a small gap in the circumferential direction. That is, the first guide surface 93a and the second guide surface 53a are combined to form an annular guide surface 100a that is annular as a whole about the combustor axis O. Furthermore, the first bell mouth 90 and the second bell mouth 50 are combined to form an annular bell mouth 100 having the annular guide surface 100a. When viewed from the insertion direction D1, the small gap between the first bell mouth 90 and the second bell mouth 50 extends obliquely with respect to the radial direction of the combustor axis O so as to follow the pair of opposing inner circumferential surfaces 24a.

[0046] <Acoustic damper> As shown in Figures 4, 7, and 8, the acoustic damper 80 is provided on the outer peripheral surface 41a of the outer cylinder 41. The acoustic damper 80 is provided within a second circumferential range θ2 on the outer peripheral surface 41a of the outer cylinder 41. The acoustic damper 80 has a plurality of acoustic covers. The acoustic damper 80 has a first acoustic cover 81, a second acoustic cover 82, and a third acoustic cover 83 that extend circumferentially within the second circumferential range θ2. The first acoustic cover 81, the second acoustic cover 82, and the third acoustic cover 83 each define a space therein.

[0047] The first acoustic cover 81 and the second acoustic cover 82 are each provided to protrude outward in the radial direction of the combustor axis O from the outer circumferential surface 41 a of the external casing 41. The first acoustic cover 81 and the second acoustic cover 82 define a space between themselves and the outer circumferential surface 41 a of the external casing 41.

[0048] The first acoustic cover 81 is provided adjacent to the extraction direction D2 side of the second extension portion 52 of the second bell mouth 50 on the outer peripheral surface 41a of the outer cylinder 41. In the installation area of ​​the first acoustic cover 81 on the outer cylinder 41, a plurality of acoustic holes 41b are formed that penetrate the outer cylinder 41 from the inside to the outside, thereby radially communicating the introduction flow path F and the space of the first acoustic cover 81.

[0049] The second acoustic cover 82 is provided on the outer peripheral surface 41a of the external casing 41 at a position adjacent to the first acoustic cover 81 on the side in the extraction direction D2. The space of the second acoustic cover 82 is in communication with the space of the first acoustic cover 81 at an end portion in the circumferential direction of the combustor axis O. The radial dimension of the second acoustic cover 82, i.e., the height of the second acoustic cover 82 in the radial direction of the combustor axis O, is greater than that of the first acoustic cover 81.

[0050] The third acoustic cover 83 is provided to protrude outward in the radial direction of the combustor axis O from the outer circumferential surface 52b of the second extension portion 52 of the second bellmouth 50. The third acoustic cover 83 is provided in a space defined between the second lip back surface 53b of the second lip 53 and the outer circumferential surface 52b of the second extension portion 52. The third acoustic cover 83 is provided adjacent to the first acoustic cover 81 in the insertion direction D1.

[0051] The space of the third acoustic cover 83 is defined between the outer peripheral surface 52b of the second extension portion 52. The space of the third acoustic cover 83 is connected to the space within the second acoustic cover 82 via a member (not shown). The respective spaces of the first acoustic cover 81, the second acoustic cover 82, and the third acoustic cover 83 are connected in sequence to form an acoustic space having dimensions for attenuating low-frequency band vibrations of the combustion vibrations of the combustor 30. The height of the third sound cover 83 is greater than the height of the first sound cover 81 and is equal to the height of the second sound cover 82.

[0052] Here, when viewed from the insertion direction D1, the first acoustic cover 81, the second acoustic cover 82, and the third acoustic cover 83 are accommodated in the second space E of the insertion hole 22. That is, the circumferential dimensions and radial dimensions of the first acoustic cover 81, the second acoustic cover 82, and the third acoustic cover 83 about the combustor axis O are set to dimensions that allow them to be accommodated in the second space E. As a result, the entire acoustic damper 80 is disposed in the second space E.

[0053] <Action and effect> According to the gas turbine 1 configured as described above, high-pressure air generated by the compressor 2 and inside the intermediate casing 20 flows into the combustor 30 through the annular opening of the inlet flow path F. The air flowing through the inlet flow path F in the discharge direction D2 turns around and receives fuel injection from the top hat nozzle 75 when it enters the inner cylinder 70. Then, as the air moves through the inner cylinder 70 in the insertion direction D1, it receives fuel injection from the pilot nozzle 73 and the main nozzle 74, and then a flame is generated in the combustion liner 72. This generates combustion gas, which is introduced into the turbine 10 from the tip of the combustion liner 72, thereby driving the turbine 10 to rotate.

[0054] In the present embodiment, the first bell mouth 90 and the second bell mouth 50 are connected to form an annular bell mouth 100 at the inlet of the introduction passage F over the entire area in the circumferential direction of the combustor axis O. The annular guide surface 100a formed by combining the first guide surface 93a of the first bell mouth 90 and the second guide surface 53a of the second bell mouth 50 allows air within the internal space of the intermediate casing 20 to flow smoothly over the entire area in the circumferential direction of the introduction passage F. This enables performance to be improved.

[0055] The combustor 30 of this embodiment is configured such that the outer casing 41 protrudes further into the internal space of the intermediate casing 20 than the inner surface 21 of the intermediate casing 20. This makes it possible to shorten the length of the combustion casing 72 through which the high-temperature combustion gas flows. As a result, the residence time of the high-temperature combustion gas in the combustion casing 72 can be shortened, and the amount of nitrogen oxides produced in the combustion casing 72 can be suppressed.

[0056] In this embodiment, in accordance with the configuration in which the outer cylinder 41 protrudes into the internal space in the insertion direction D1, the first bell mouth 90 is provided so as to protrude further in the insertion direction D1 than the outer cylinder 41. Therefore, the first bell mouth 90 and the first guide surface 93a can be disposed at an appropriate position before the direction in which air flows into the introduction flow path F. This allows air to be smoothly introduced into the introduction flow path F over the first circumferential range θ1.

[0057] Furthermore, in the second circumferential range θ2 where the first bell mouth 90 is not arranged, there is a second bell mouth 50 that is provided integrally with the tip of the outer cylinder 41. This allows air to be smoothly introduced into the introduction flow path F over the second circumferential range θ2. Furthermore, due to the presence of the second bell mouth 50, it is sufficient that the installation range of the first bell mouth 90 on the inner surface 21 of the intermediate casing 20 is limited to only the first circumferential range θ1, which is a part of the range, rather than the entire range in the circumferential direction about the combustor axis O. This makes it possible to minimize the work range for installing the first bell mouth 90 inside the intermediate casing 20, which is a narrow location. As a result, it is possible to avoid complicating the work and improve workability.

[0058] When the combustor 30 is attached to the gas turbine 1, the combustion liner 72 of the combustor 30 is first inserted into the insertion hole 22 to attach the combustion liner to the inlet of the gas turbine 1. Thereafter, an assembly consisting of the remaining components of the combustor 30, such as the outer liner 41 and inner liner 70, is inserted into the insertion hole 22 and connected to the combustion liner 72.

[0059] In the present embodiment, the insertion hole 22 is an elongated hole formed by a first space M and a second space E, and the external cylinder 41 is inserted into the first space M. At this time, because the outer diameter dimension of the external cylinder 41 corresponds to the inner diameter dimension of the first space M, the external cylinder 41 can be disposed without forming any wasted space. Then, in the process of inserting the above-described assembly into the insertion hole 22, the second bell mouth 50 accompanying the external cylinder 41 passes through the second space E that bulges out from the first space M. Therefore, the second bell mouth 50 does not interfere with the inner circumferential surface of the insertion hole 22, and the combustor 30 can be easily inserted into the insertion hole 22. This improves the workability when installing the combustor 30.

[0060] Furthermore, by passing through the second space E, the second bell mouth 50 of the combustor 30 inserted into the insertion hole 22 is naturally disposed in the second circumferential range θ2. Therefore, there is no need to perform circumferential positioning of the combustor 30 after inserting the combustor 30, which can further improve workability.

[0061] Furthermore, the acoustic damper 80 provided on the outer peripheral surface 41a of the outer cylinder 41 is configured to pass through the second space E, just like the second bell mouth 50, so that interference of the acoustic damper 80 with the inner peripheral surface of the insertion hole 22 can be avoided.

[0062] Furthermore, by arranging the second extension portion 52 of the second bell mouth 50 so as to protrude from the tip of the outer cylinder 41 in the insertion direction D1, it is possible to expand the installation space on the outer peripheral surface 41a side of the outer cylinder 41. Then, by installing the first acoustic cover 81, which is part of the acoustic damper 80, on the outer peripheral surface 52b of such second extension portion 52, it is possible to make effective use of the space.

[0063] Furthermore, the outer peripheral surface 52b of the second extension portion 52 is located radially inward of the outer peripheral end portion of the second lip 53. As a result, the space defined by the second lip 53 and the second extension portion 52 is located radially inward of the end portion of the second lip 53 that is located radially outward of the combustor axis O. This makes it possible to reduce the radial height of the first acoustic cover 81 installed in this space while improving space efficiency. Thus, the inner peripheral surface of the insertion hole 22 can have a minimum size that allows the acoustic damper 80 to pass through, thereby avoiding unnecessary expansion of the space.

[0064] The first bell mouth 90 is detachably attached to the inner surface 21 of the intermediate casing 20. Therefore, when the insertion hole 22 is changed, it is only necessary to change the dimension of the rise of the first bell mouth 90 from the inner surface 21 of the intermediate casing 20, without changing the size of the intermediate casing 20. This makes it possible to flexibly accommodate design changes and also allows the first bell mouth 90 to be retrofitted to an intermediate casing 20 of an existing size. The attachment work of the first bell mouth 90 may be performed either before or after the combustor 30 is inserted into the insertion hole 22.

[0065] Furthermore, as viewed from the insertion direction D1, the gap between the first end surface 90a and the second end surface 50a of the first bell mouth 90 extends at an angle with respect to the radial direction of the combustor axis O. Therefore, the dimension of the gap as viewed from the insertion direction D1 can be made longer than in a case where the gap extends in the radial direction of the combustor axis O. This can increase the pressure loss of the air entering the gap and reduce the flow rate of the air flowing in through the gap without relying on the annular guide surface 100a. As a result, performance degradation can be suppressed.

[0066] Second Embodiment Next, a gas turbine 101 according to a second embodiment of the present invention will be described with reference to Fig. 9 to Fig. 12. In the second embodiment, the same components as those in the description of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. In the second embodiment, the configuration of the first bell mouth in particular is different from that of the first embodiment.

[0067] As shown in Fig. 9 , a gas turbine 101 of the second embodiment further includes a support member 7 that connects a combustion liner 72 and an intermediate casing 20. The support member 7 supports the combustor 30 from the radial outside of the combustor axis O. One end of the support member 7 is connected to the combustion liner 72. One end of the support member 7 extends toward the front side of the page in Fig. 9 and is smoothly connected to the combustion liner 72. The other end of the support member 7 is connected to the inner surface 21 of the intermediate casing 20. In addition, the gas turbine 101 of the second embodiment includes a first bellmouth 200 that has a structure different from that of the first embodiment.

[0068] <First Bellmouth> As shown in Fig. 10 , the first bell mouth 200 according to the second embodiment is divisible into a plurality of pieces. The first bell mouth 200 has a plurality of bell mouth segments 210. The multiple bell mouth segments 210 are each detachably fixed to the circumferential edge of the insertion hole 22 on the inner surface 21 of the intermediate casing 20. The multiple bell mouth segments 210 are arranged side by side in the circumferential direction of the combustor axis O. That is, the first bell mouth 200 has a plurality of bell mouth segments 210 that are arranged side by side in the circumferential direction of the combustor axis O and that are divisible from one another. The first bell mouth 200 of the second embodiment has three bell mouth segments 210.

[0069] Of the three bellmouth segments 210, the bellmouth segment 210 that is not adjacent to the second bellmouth 50 at both ends in the circumferential direction about the combustor axis O is referred to as a first bellmouth segment 211. Of the three bellmouth segments 210, two bellmouth segments 210 that are adjacent to the second bellmouth 50 at one end in the circumferential direction about the combustor axis O are referred to as second bellmouth segments 212. In other words, the first bellmouth segment 211 is adjacent to the second bellmouth segment 212 at both ends in the circumferential direction about the combustor axis O. In other words, the first bellmouth 200 has the first bellmouth segment 211 and the second bellmouth segment 212. The first bellmouth segment 211 and the second bellmouth segment 212 face each other across a gap in the circumferential direction about the combustor axis O.

[0070] <First bellmouth segment> The bellmouth first segment 211 is disposed at a position overlapping with the support member 7 in the circumferential direction of the combustor axis O. In other words, when viewed from the insertion direction D1 (removal direction D2), at least a portion of the bellmouth first segment 211 and the support member 7 overlap in the circumferential direction of the combustor axis O. As shown in FIGS. 10 and 11 , the bellmouth first segment 211 has a first portion 220, a second portion 230, a blocking portion 232, and a guide portion 234. Furthermore, the bellmouth first segment 211 is fixed to the intermediate casing 20 by a plurality of fasteners 240.

[0071] <First part> The first portion 220 has a plate shape with its thickness direction aligned with the insertion direction D1. The first portion 220 extends over a part of the first circumferential range θ1. In other words, the first portion 220 extends to a position within the first circumferential range θ1 where it does not come into contact with the bellmouth second segment 212. A surface of the first portion 220 facing the extraction direction D2 abuts against the circumferential edge portion of the insertion hole 22 on the inner surface 21 of the intermediate casing 20. That is, the first portion 220 extends in the radial direction of the combustor axis O in contact with the circumferential edge portion of the insertion hole 22. The first portion 220 is detachably fixed to the intermediate casing 20.

[0072] <Fixing holes and fixtures> Furthermore, the first portion 220 is formed with fixing holes 222 through which the fixing devices 240 can be inserted. A plurality of fixing holes 222 are formed corresponding to the fixing devices 240. The plurality of fixing holes 222 are formed at intervals in the circumferential direction of the combustor axis O. FIG. 12 is a schematic diagram of the fixing devices 240 and the fixing holes 222. In the second embodiment, the bellmouth first segment 211 is fixed to the intermediate casing 20 by four fixing devices 240. Furthermore, four fixing holes 222 are formed in the bellmouth first segment 211. The fixing holes 222 include reamer bolt holes 224 and through holes 226.

[0073] The reamer bolt hole 224 is one of the four fixing holes 222. The reamer bolt hole 224 is formed so that the fixing device 240 is inserted therethrough with a first gap between the fixing device 240 and the reamer bolt hole 224. In other words, the fixing device 240 is inserted through at least one of the fixing holes 222 with a first gap between the fixing device 240 and the reamer bolt hole 224. In addition, in the second embodiment, an example is described in which the reamer bolt hole 224 is formed to have a fit tolerance with the fixing device 240. In other words, in the second embodiment, an example is described in which the first gap is zero. In addition, the fixing device 240 inserted through the reamer bolt hole 224 among the multiple fixing devices 240 is referred to as a reamer bolt 242. The reamer bolt 242 has a shaft portion 243, a threaded portion 244, and a head portion 245.

[0074] The shaft portion 243 is a portion that overlaps with the reamer bolt hole 224 in the insertion direction D1 (removal direction D2). The shaft portion 243 is formed in a cylindrical shape with no threads formed on its outer periphery. The shaft portion 243 is formed so that its outer diameter is slightly larger than the inner diameter of the reamer bolt hole 224. The threaded portion 244 is a portion that overlaps with the intermediate casing 20 in the insertion direction D1 (removal direction D2). That is, the threaded portion 244 is a portion that extends from the shaft portion 243 in the removal direction D2. The threaded portion 244 has a thread formed on its outer periphery. The threaded portion 244 can be threaded into a screw groove formed in the intermediate casing 20. The head portion 245 is a portion that extends from the shaft portion 243 in the insertion direction D1. The head portion 245 is formed so that its outer diameter is sufficiently larger than the inner diameter of the reamer bolt hole 224. A washer 250 is provided between the head 245 and the first portion 220 in the insertion direction D1. The washer 250 is inserted onto the shaft portion 243 and is formed in an annular shape with an outer diameter larger than that of the head 245.

[0075] Of the four fixing holes 222, three of them, excluding the reamer bolt hole 224, are formed as through holes 226. The through holes 226 are formed so that the fixing device 240 is inserted therethrough with a second gap between them. The second gap is larger than the first gap. That is, the through holes 226 are not in contact with the fixing device 240. That is, the fixing device 240 is inserted through at least one of the fixing holes 222 with a second gap between them, the second gap being larger than the first gap. The inner diameter of the through holes 226 is larger than the inner diameter of the reamer bolt hole 224. Furthermore, of the multiple fixing devices 240, the fixing device 240 inserted through the through holes 226 is referred to as a through bolt 246. The through bolt 246 has substantially the same structure as the reamer bolt 242, and its outer circumferential surface is formed so as not to come into contact with the through hole 226. A washer 250 is also provided between the through-bolt 246 and the first portion 220 .

[0076] Furthermore, the multiple fixing holes 222 are arranged in a row around the combustor axis O. That is, the reamer bolt hole 224 and the multiple through holes 226 are arranged in a row around the combustor axis O. The reamer bolt hole 224 is arranged at a position among the multiple fixing holes 222 arranged in the circumferential direction of the combustor axis O, excluding both end ends. In other words, the reamer bolt hole 224 is arranged at a position closer to the center among the multiple fixing holes 222 arranged in the circumferential direction of the combustor axis O. That is, the through holes 226 are arranged at positions located at both end ends of the multiple fixing holes 222 arranged in the circumferential direction of the combustor axis O. That is, the fixing holes 222 through which the fastener 240 is inserted with the first gap formed are arranged at positions among the multiple fixing holes 222 arranged in the circumferential direction of the combustor axis O, excluding both circumferential ends.

[0077] <Occluded part> The blocking portion 232 is formed to rise in the insertion direction D1 from the entire circumferential area of ​​a radially outer edge portion of the first portion 220. The blocking portion 232 has a plate shape extending in an arc with its thickness direction aligned with the radial direction of the combustor axis O. As shown in FIG. 11 , the blocking portion 232 is formed such that its end in the insertion direction D1 is located further in the extraction direction D2 than the tip of the outer casing 41. The blocking portion 232 is connected to the second portion 230 at its end in the insertion direction D1.

[0078] <Second part> The second portion 230 is disposed at a distance from the first portion 220 in the insertion direction D1. The second portion 230 extends in a radial direction of the combustor axis O. The second portion 230 has a plate shape with its thickness direction aligned with the insertion direction D1. That is, the second portion 230 is formed in the same manner as the first portion 220 in which no fixing hole 222 is formed. Moreover, the second portion 230 is connected to the blocking portion 232 over the entire circumferential area of ​​a radially outer edge portion thereof.

[0079] That is, the blocking portion 232 connects the first portion 220 and the second portion 230 so as to close their ends on the radially outer side with respect to the combustor axis O. Furthermore, the blocking portion 232 is formed so as to rise from the circumferentially outer edge portion of the first portion 220 in the insertion direction D1 and connect to the second portion 230. That is, the blocking portion 232 closes the first portion 220 and the second portion 230 on all surfaces except for the radially inner side.

[0080] Furthermore, an open space S that opens radially inward with respect to the combustor axis O is defined by the first portion 220, the second portion 230, and the closing portion 232. In other words, the open space S is a space that opens toward the insertion hole 22 when the external cylinder 41 is not inserted. Moreover, the open space S is a space that opens only radially inward with respect to the combustor axis O when the external cylinder 41 is not inserted. Furthermore, the entire opening of the open space S that opens radially inward is closed by the external cylinder 41 when the external cylinder 41 is inserted.

[0081] <Information Department> The guide portion 234 is formed to rise from the entire circumferential direction of a radially inner edge portion of the second portion 230 in the insertion direction D1. The guide portion 234 has a plate shape extending in an arc with its thickness direction aligned with the radial direction of the combustor axis O. An inner circumferential surface of the guide portion 234 facing radially inward forms a cylindrical surface centered on the combustor axis O. The inner circumferential surface of the guide portion 234 facing radially inward abuts against or faces an outer circumferential surface 41a of the outer cylinder 41 with a small gap therebetween.

[0082] Furthermore, a first guide surface 235 is formed in the guide portion 234 at a portion facing radially inward at a tip end in the insertion direction D1. The first guide surface 235 is configured to be able to guide air toward the introduction flow path F. The first guide surface 235 has a convex curved surface shape that decreases in diameter toward the extraction direction D2, which is the direction in which air is introduced into the introduction flow path F. The first guide surface 235 has a convex curved surface shape that extends in a curved manner so as to widen radially outward from the combustor axis O toward the insertion direction D1. The first guide surface 235 is smoothly connected to the inner circumferential surface of the second portion 230. In other words, the guide portion 234 extends in the insertion direction D1 from a radially inner end of the second portion 230 and has the first guide surface 235 at its end in the insertion direction D1.

[0083] <Second bellmouth segment> The bellmouth second segment 212 is disposed at a position where it does not overlap with the support member 7 in the circumferential direction of the combustor axis O. As shown in FIG. 10 , the bellmouth second segment 212 has a structure in which the first bellmouth 90 according to the first embodiment is divided. Therefore, a detailed description of the structure of the bellmouth second segment 212 will be omitted, but only the manner of fixation to the intermediate casing 20 differs from the first embodiment. Like the bellmouth first segment 211, the bellmouth second segment 212 is fixed to the intermediate casing 20 by a plurality of fasteners 240.

[0084] The bellmouth second segment 212 is fixed to the intermediate casing 20 by inserting multiple fasteners 240 into the attachment portion 91. That is, multiple fastening holes 222 are formed in the attachment portion 91. Like the bellmouth first segment 211, the bellmouth second segment 212 is formed with one reamer bolt hole 224 and three through holes 226. A reamer bolt 242 is inserted into the reamer bolt hole 224. A through bolt 246 is inserted into the through hole 226. The reamer bolt holes 224 are arranged in positions excluding both end portions of the multiple fastening holes 222 aligned in the circumferential direction of the combustor axis O. That is, in the bellmouth second segment 212, a fastener 240 is inserted into at least one of the multiple fastening holes 222 with a first gap formed between the fastener 240 and the fixing hole 222. Furthermore, the fastener 240 is inserted through at least one of the multiple fixing holes 222 with a second gap, which is a gap larger than the first gap, formed between the fixing hole 222 and the fixing hole 240. Furthermore, the fixing hole 222 through which the fastener 240 is inserted with the first gap formed is arranged at a location among the multiple fixing holes 222 arranged in the circumferential direction of the combustor axis O, excluding both circumferential ends.

[0085] Furthermore, the first guide surface 235 of the bell mouth first segment 211, the first guide surface 93a of the bell mouth second segment 212, and the second guide surface 53a of the second bell mouth 50 are smoothly connected via a small gap in the circumferential direction. That is, the first guide surface 93a, the first guide surface 235, and the second guide surface 53a are combined to form an annular guide surface 100a that as a whole forms an annular shape centered on the combustor axis O. Furthermore, the first bell mouth 200 and the second bell mouth 50 are combined to form an annular bell mouth 100 having the above-mentioned annular guide surface 100a.

[0086] <Gas turbine assembly procedure> The gas turbine 101 according to the second embodiment as described above is assembled in the following order. First, the combustion liner 72 is attached to the inside of the intermediate casing 20. The combustion liner 72 is connected to the support member 7 and connected to the intermediate casing 20 via the support member 7. After the combustion liner 72 and the support member 7 are connected, the first bellmouth 200 and the second bellmouth 50 are attached to the intermediate casing 20. Of the first bellmouth 200, the two bellmouth second segments 212 are attached to the intermediate casing 20 from inside the intermediate casing 20. Meanwhile, the bellmouth first segment 211 is attached to the intermediate casing 20 from outside the casing. Specifically, an operator accesses the casing from outside through the insertion hole 22 and attaches the bellmouth first segment 211 to the casing.

[0087] Furthermore, when attaching the first bell mouth segment 211 and the second bell mouth segment 212, first the reamer bolt 242 is inserted into the reamer bolt hole 224 and fixed. The first bell mouth segment 211 and the second bell mouth segment 212 are positioned by being fixed with the reamer bolt 242. After the first bell mouth segment 211 and the second bell mouth segment 212 have been positioned, three through bolts 246 are inserted and fixed. After the first bell mouth 200 and the second bell mouth 50 have been attached to the intermediate casing 20, the outer cylinder 41 and the inner cylinder 70 are inserted into the insertion hole 22. At this time, the outer cylinder 41 and the inner cylinder 70 may be inserted into the insertion hole 22 as an assembled unit, or the outer cylinder 41 and the inner cylinder 70 may be inserted separately.

[0088] <Action and effect> According to the gas turbine 101 according to the second embodiment described above, similarly to the first embodiment, the annular guide surface 100a allows the air in the internal space of the intermediate casing 20 to smoothly flow into the entire circumferential area of ​​the introduction flow path F. Therefore, the configuration of the second embodiment also makes it possible to improve performance.

[0089] In the second embodiment, the first bell mouth 200 has multiple bell mouth segments 210 that can be separated in the circumferential direction. Specifically, the first bell mouth 200 can be separated into three pieces: a first bell mouth segment 211 and two second bell mouth segments 212. This allows the first bell mouth 200 to be attached and detached individually in a state where it is separated into bell mouth segments 210. Because the bell mouth segments 210 can be attached and detached individually, they can be attached and detached in a state where their weight is reduced by being separated. Therefore, the first bell mouth 200 can be easily attached and detached. In other words, the workability related to attaching and detaching the first bell mouth 200 can be improved.

[0090] Furthermore, an open space S is formed in the bellmouth first segment 211 by the first portion 220, the second portion 230, and the closing portion 232. The open space S is open toward the inside in the radial direction of the combustor axis O. In other words, the open space S is open toward the insertion hole 22 when the outer casing 41 is not inserted. Therefore, an operator can attach and detach the bellmouth first segment 211 to and from the intermediate casing 20 from outside the intermediate casing 20 via the insertion hole 22. Therefore, with the bellmouth first segment 211 configured in this way, the work area for installing the first bellmouth 200 inside the intermediate casing 20, which is a narrow space, can be minimized.

[0091] Furthermore, with the outer cylinder 41 inserted, the opening of the open space S formed in the bellmouth first segment 211 facing radially inward is closed by the outer cylinder 41. This prevents air from flowing into the open space S while the combustor 30 is in operation. In other words, it is possible to suppress the occurrence of loss due to air flowing into the open space S.

[0092] In the second embodiment, the support member 7 is disposed at a position overlapping with the bellmouth first segment 211 in the circumferential direction of the combustor axis O. The bellmouth first segment 211 in which the open space S is formed makes it possible to install the first bellmouth 200 even when the support member 7 makes it difficult to perform work from inside the intermediate casing 20. Furthermore, the bellmouth first segment 211 is fixed to the intermediate casing 20 after the support member 7 is attached. This makes it possible to avoid interference between the bellmouth first segment 211 and installation tools, etc., when attaching the support member 7. Therefore, the bellmouth first segment 211 in which the open space S is formed can suppress a decrease in workability during attachment and detachment, even in a gas turbine 101 that is equipped with the support member 7.

[0093] Moreover, in the second embodiment, only the first bellmouth segment 211 of the bellmouth segments 210 has a structure that includes the open space S. That is, the second bellmouth segment 212 does not have an open space S. The first bellmouth segment 211 protrudes in the radial direction of the combustor axis O compared to the second bellmouth segment 212. Furthermore, the second bellmouth segment 212 is disposed at a location closer to the adjacent insertion holes than the first bellmouth segment 211. Therefore, since the second bellmouth segment 212 does not have an open space S, the intervals between the insertion holes 22 formed around the rotor axis A can be narrowed. That is, the intervals at which the multiple combustors 30 are disposed can be narrowed.

[0094] Furthermore, each bellmouth segment 210 is fixed to the intermediate casing 20 by a reamer bolt 242 and a through bolt 246. The reamer bolt 242 is inserted through the reamer bolt hole 224, leaving a first gap. The through bolt 246 is inserted through the through hole 226, leaving a second gap. In the second embodiment, the first gap is zero. That is, the reamer bolt 242 is in contact with the reamer bolt hole 224. Therefore, the bellmouth segment 210 is positioned by fixing the reamer bolt 242. After the bellmouth segment 210 is positioned by the reamer bolt 242, it is further fixed by the through bolt 246. Furthermore, the through bolt 246 is inserted through the through hole 226 without coming into contact with it. This allows the second gap to buffer thermal expansion of the bellmouth segment 210 and the through bolt 246. Therefore, by providing a second gap between through-bolt 246 and through-hole 226 that is larger than the first gap, it is possible to ensure a margin for thermal expansion.

[0095] Furthermore, the reamer bolt holes 224 and the through holes 226 are arranged side by side in the circumferential direction of the combustor axis O. The reamer bolt holes 224 are arranged at locations of the arranged fixing holes 222 (reamer bolt holes 224 and through holes 226) excluding both circumferential ends. In other words, the reamer bolt holes 224 are arranged at locations closer to the center of the multiple fixing holes 222 arranged side by side in the circumferential direction of the combustor axis O. According to this positional relationship, the bellmouth segments 210 can be positioned by the reamer bolts 242 and the reamer bolt holes 224 at a location closer to the center. In other words, the bellmouth segments 210 can be positioned with higher accuracy.

[0096] <Other embodiments> The above describes in detail the embodiments of the present disclosure with reference to the drawings, but the specific configuration is not limited to this embodiment, and design changes and the like are also included within the scope that does not deviate from the gist of the present disclosure.

[0097] For example, the insertion hole 22 in each embodiment is configured to include a first space M that has a true shape when viewed from the insertion hole 22 and a second space E that bulges out from the first space M, but this is not limited to this. For example, the insertion hole 22 may have a true circular shape when viewed from the insertion direction D1. In this case, the inner diameter of the insertion hole 22 may be set larger than the outer diameter of the outer cylinder 41 so that the second bell mouth 50 and the like can pass through.

[0098] Furthermore, the insertion hole 22 in each embodiment may have an elliptical or elongated hole shape of a minimum size, as viewed from the insertion direction D1, that allows the outer cylinder 41 and the second bell mouth 50 protruding from the outer peripheral surface 41 a of the outer cylinder 41 in the radial direction of the combustor axis O to pass through.

[0099] Furthermore, the angular ranges of the first circumferential range θ1 in which the first bell mouths 90, 200 are installed and the second circumferential range θ2 in which the second bell mouth 50 is installed in each embodiment may be changed as appropriate. The first circumferential range θ1 may be set to an angular range smaller than the second circumferential range θ2, and the circumferential dimension of the first bell mouths 90, 200 may be smaller than the circumferential dimension of the second bell mouth 50.

[0100] Furthermore, in each embodiment, the first end face 90a of the first bell mouth 90, 200 and the second end face 50a of the second bell mouth 50 were configured to face each other with a gap therebetween, but the first end face 90a and the second end face 50a may also be configured to abut against each other with no gap in the circumferential direction. This makes it possible to prevent air from leaking into the introduction flow path F through the gap.

[0101] Furthermore, the first bell mouths 90, 200 and second bell mouths 50 in each embodiment are not limited to the configurations in the embodiments, and various configurations can be adopted as long as they have the first guide surfaces 93a, 235 and the second guide surfaces 53a.

[0102] The configuration of the fastener 240 and fastening hole 222 of the second embodiment may also be applied to the other embodiments. Furthermore, the configuration of the fastener 240 and fastening hole 222 of the second embodiment may also be applied to the second bell mouth 50 according to each embodiment.

[0103] Furthermore, although the first bellmouth segment 211 and the second bellmouth segment 212 in the second embodiment are configured to face each other with a gap interposed therebetween in the circumferential direction of the combustor axis O, the present invention is not limited to this. That is, the first bellmouth segment 211 and the second bellmouth segment 212 may be configured to abut each other without a gap interposed therebetween in the circumferential direction. With such a configuration, it is possible to prevent air from leaking into the introduction flow path F through the gap.

[0104] Furthermore, the reamer bolt 242 and the reamer bolt hole 224 in the second embodiment are not limited to being formed to have a fit tolerance. The reamer bolt 242 and the reamer bolt hole 224 may be formed so as to enable positioning of the bell mouth first section 211. Specifically, the reamer bolt 242 may be formed so that the outer diameter of the shank 243 is the same as the inner diameter of the reamer bolt hole 224, or so that there is a slight gap between the shank 243 of the reamer bolt 242 and the reamer bolt hole 224.

[0105] Furthermore, the first gap and the second gap associated with fixing hole 222 and fixing device 240 in the second embodiment may be adjusted by either fixing hole 222 or fixing device 240. Specifically, reamer bolt hole 224 may be formed larger than through hole 226, or the inner diameters of reamer bolt hole 224 and through hole 226 may be formed to be the same and the outer diameter of shank 243 of reamer bolt 242 may be formed larger than the outer diameter of through bolt 246. Furthermore, reamer bolt hole 224 may be formed larger than through hole 226, and the outer diameter of shank 243 of reamer bolt 242 may be formed larger than the outer diameter of through bolt 246.

[0106] Furthermore, the bellmouth second segment 212 may have the same structure as the bellmouth first segment 211. Specifically, the bellmouth second segment 212 may have the same open space S as the bellmouth first segment 211. This makes it possible to attach and detach the bellmouth second segment 212 from the outside of the intermediate casing 20. Therefore, workability can also be improved for the bellmouth second segment 212. This type of structure may be applied as appropriate, for example, depending on the distance between adjacent insertion holes 22. Both of the two bellmouth second segments 212 may have the open space S, or only one of the bellmouth second segments 212 may have the open space S.

[0107] Furthermore, the first bell mouth 200 of the second embodiment is not limited to a form that can be divided into three bell mouth segments 210. The first bell mouth 200 may be divisible into two bell mouth segments, or may be divisible into four or more bell mouth segments.

[0108] Furthermore, the bellmouth second segment 212 in the second embodiment is not limited to being attached to the intermediate casing 20 at the same time as the bellmouth first segment 211. Because the bellmouth second segment 212 does not hinder the attachment of the support member 7, it may be fixed to the intermediate casing 20 before the support member 7 is attached, for example.

[0109] <Additional Notes> The gas turbines 1 and 101 described in the respective embodiments can be understood, for example, as follows.

[0110] (1) A gas turbine (1, 101) according to a first aspect includes a rotatable rotor, a casing (20) that surrounds the rotor from an outer periphery side and has an insertion hole (22) that penetrates from inside to outside, and a combustor (30) that is inserted into the insertion hole (22) from outside the rotor, wherein the combustor (30) includes an outer casing (41) that extends about a combustor axis (O) and has a tip that protrudes further into the casing (20) than the insertion hole (22), and an inner casing (70) that is disposed inside the outer casing (41) and forms an annular introduction flow path (F) that opens toward an insertion direction (D1) of the combustor (30) between the outer casing (41) and the inner casing (70), and a first bell mouth (90, 200) provided at a tip of the external cylinder (41) and extending over a second circumferential range (θ2) excluding the first circumferential range (θ1) in the circumferential range, and having a first guide surface (93 a, 235) that guides air to the introduction flow path (F); and a second bell mouth (50) provided at a tip of the external cylinder (41) and extending over a second circumferential range (θ2) excluding the first circumferential range (θ1) in the circumferential range, and having a second guide surface (53 a) that guides air to the introduction flow path (F). The first guide surface (93 a) and the second guide surface (53 a) are connected to each other in the circumferential direction, thereby forming an annular guide surface (100 a).

[0111] According to the gas turbines 1, 101, the air can be smoothly introduced into the introduction flow passage F over the entire circumference by the annular guide surface 100a formed by the first guide surfaces 93a, 235 and the second guide surface 53a. Furthermore, since the first bell mouths 90, 200 extend further in the insertion direction D1 than the inner surface 21 of the casing 20, air can be appropriately guided into the introduction flow path F of the combustor 30. Furthermore, due to the presence of the second bell mouth 50, it is sufficient that the first bell mouths 90, 200 are installed only partially, rather than over the entire circumferential range of the inner surface 21 of the casing 20. Therefore, the work of attaching the first bell mouths 90, 200 to the inner surface 21 of the casing 20 can be avoided from becoming complicated.

[0112] (2) A gas turbine (1, 101) according to a second aspect is the gas turbine (1, 101) described in (1), in which the insertion hole (22) includes: a first space M that is a space within an imaginary circle C centered on the combustor axis O; and a second space E that is a space formed by extending a portion of the imaginary circle C in the second circumferential range θ2 radially outward from the rotor, as viewed from the insertion direction (D1); the outer cylinder (41) has an outer diameter corresponding to the imaginary circle C and is disposed within the first space M as viewed from the insertion direction (D1); and the second bell mouth (50) is located within the second space E as viewed from the insertion direction (D1).

[0113] As a result, when the outer casing 41 of the combustor 30 is inserted into the first space M of the insertion hole 22, the second bell mouth 50 passes through the second space E of the insertion hole 22. Therefore, the combustor 30 can be easily inserted into the insertion hole 22.

[0114] (3) The gas turbine (1, 101) according to a third aspect is the gas turbine (1, 101) according to (2), further including an acoustic damper (80) that is provided in the second circumferential range θ2 on the outer peripheral surface 41 a of the outer casing (41), that protrudes radially outward from the combustor axis O more than the first bell mouth (90, 200), and that is located within the second space E as seen from the insertion direction (D1).

[0115] This makes it possible to prevent the acoustic damper 80 provided on the outer peripheral surface 41 a of the outer casing 41 from interfering with the insertion hole 22 when inserting the outer casing 41 of the combustor 30 into the insertion hole 22 .

[0116] (4) A gas turbine (1, 101) according to a fourth aspect is the gas turbine (1, 101) described in (3), in which the second bell mouth (50) includes: a second extension portion (52) that is integral with the external cylinder (41) and protrudes from a tip of the external cylinder (41) in the insertion direction (D1); and a second lip (53) that extends from the tip of the second extension portion (52) radially outwardly of the combustor axis (O) and forms the second guide surface (53 a), and at least a part of the acoustic damper (80) is provided on an outer peripheral surface (52 b) of the second extension portion (52).

[0117] By also installing the acoustic damper 80 on the outer peripheral surface 52b of the second extension portion 52, it is possible to secure a large installation space for the acoustic damper 80. However, the outer peripheral surface 52b of the second extension portion 52 is located radially inward of the outer peripheral end of the second lip 53. Therefore, the radial height of the acoustic damper 80 installed on the outer peripheral surface 52b can be reduced.

[0118] (5) A gas turbine (1, 101) according to a fifth aspect is the gas turbine (1, 101) of any one of (1) to (4), wherein the first bell mouth (90) has: an attachment portion (91) detachably fixed to a peripheral portion of the insertion hole (22) on the inner surface (21) of the casing (20); a first extension portion (92) protruding from the attachment portion (91) in the insertion direction (D1); and a first lip (93) extending from a tip of the first extension portion (92) radially outward from the combustor axis (O) and forming the first guide surface (93 a).

[0119] This allows the first bell mouth 90 to be easily attached to and detached from the inner surface 21 of the casing 20, and also allows the first guide surface 93a to be positioned appropriately in accordance with the position of the introduction flow path F.

[0120] (6) A gas turbine 1, 101 according to a sixth aspect is the gas turbine 1, 101 of any one of (1) to (5), wherein the first bell mouth 90, 200 and the second bell mouth 50 have circumferential end faces 50a, 90a that face each other in the circumferential direction with a gap between them, and the gap extends at an angle with respect to the radial direction of the combustor axis O as viewed from the insertion direction D1.

[0121] This makes it possible to reduce the amount of air that flows into the introduction flow path F by passing through the gap without passing through the annular guide surface 100a.

[0122] (7) A gas turbine 101 according to a seventh aspect is the gas turbine 101 of any one of (1) to (6), in which the first bell mouth 200 has a plurality of bell mouth segments 210 that are arranged side by side in the circumferential direction and can be separated from one another.

[0123] This allows the first bell mouth 200 to be separated and each section to be attached and detached. Therefore, since it can be attached and detached in a separated state with reduced weight, the first bell mouth 200 can be easily attached and detached.

[0124] (8) A gas turbine 101 according to an eighth aspect is the gas turbine 101 according to (7), wherein the bellmouth segment 210 includes: a first portion 220 in contact with the peripheral portion and extending in a radial direction about the combustor axis O; a second portion 230 disposed at a distance from the first portion 220 in the insertion direction D1 and extending in the radial direction; a blocking portion 232 connecting the first portion 220 and the second portion 230 to close an end portion thereof on an outer side in the radial direction of the combustor axis O; and a guide portion 234 extending from an end portion of the second portion 230 on an inner side in the radial direction of the combustor axis O in the insertion direction D1 and having the first guide surface 235 at an end portion thereof in the insertion direction D1, and wherein an opening space S that opens radially inward is formed by the first portion 220, the second portion 230, and the blocking portion 232.

[0125] This allows the bellmouth segment 210 to be attached and detached through the open space S from the radially inner side of the combustor axis O. Therefore, the bellmouth segment 210 can be attached and detached from the outside of the casing 20, improving workability.

[0126] (9) A ninth aspect of the gas turbine 1, 101 is the gas turbine 1, 101 of any one of (1) to (8), wherein the first bell mouth 90, 200 further has a plurality of fasteners 240 that fasten to the casing 20, the first bell mouth 90, 200 has a plurality of fastening holes 222 formed therein through which the fasteners 240 can be inserted, at least one of the plurality of fastening holes 222 has the fastener 240 inserted therethrough with a first gap between it and the fastener 240, and at least one of the plurality of fastening holes 222 has the fastener 240 inserted therethrough with a second gap between it and the fastener 240 that is larger than the first gap.

[0127] The first bell mouths 90, 200 are positioned by combining the fixing hole 222 having the first gap with the fixing device 240. Furthermore, the combination of the fixing hole 222 having the second gap with the fixing device 240 ensures a tolerance for thermal expansion.

[0128] (10) A gas turbine 1, 101 according to a tenth aspect is the gas turbine 1, 101 of (9), in which the plurality of fixing holes 222 are arranged in a row in the circumferential direction, and the fixing hole 222 through which the fixing device 240 is inserted with the first gap formed is arranged at a location of the plurality of fixing holes 222 arranged in the circumferential direction excluding both ends in the circumferential direction.

[0129] This allows the first bell mouths 90, 200 to be positioned more reliably while ensuring a margin for thermal expansion.

[0130] (11) A combustor 30 according to an eleventh aspect includes: an outer cylinder 41 that extends about a combustor axis O, has an insertion hole 22 penetrating from the inside to the outside of the casing, and has a tip that protrudes into the casing beyond the insertion hole; an inner cylinder 70 that is disposed inside the outer cylinder 41 and forms, between the outer cylinder 41 and the inner cylinder 70, an annular introduction flow passage F that opens toward an insertion direction D1 that is a direction in which the outer cylinder 41 is inserted into the casing 20; and an inner cylinder 70 that is provided on an inner surface 21 of the casing 20 so as to rise from a peripheral portion of the insertion hole 22 in the insertion direction D1 and that protrudes in the insertion direction D1 from the outer cylinder 41. and a second bell mouth 50 provided at the tip of the outer cylinder 41, extending over a second circumferential range θ2 excluding the first circumferential range θ1 in the circumferential range and having a second guide surface 53 a that guides air to the introduction flow path F, and the first guide surfaces 93 a, 235 and the second guide surface 53 a are connected to each other in the circumferential direction to form an annular guide surface 100 a. [Explanation of symbols]

[0131] 1. Gas turbine 2 Compressor 3 Compressor rotor 4 Compressor casing 5 Compressor rotor blade stage 6 Compressor stator stage 10 Turbine 11 Turbine rotor 12 Turbine casing 13 Turbine blade stage 14 Turbine stator stage 15 Gas turbine rotor 20 Intermediate casing (casing) 21 Inner 22 Insertion hole 23 First inner peripheral surface 24 Second inner peripheral surface 24a Opposing inner circumferential surface 24b Cylinder inner surface 25 Gas turbine casing 30 Combustor 40 Outer cylinder unit 41 Outer cylinder 41a Outer surface 41b Acoustic hole 42 Mounting flange 42a flange bolt 50 Second Bellmouth 50a Second end face 52 Second extension 52a Inner surface 52b Outer surface 53 Second Lip 53a Second guide surface 53b Second lip back 60 End cover 70 Inner cylinder 71 Strut 72 Combustion tube 73 Pilot nozzle 74 Main nozzle 75 Top Hat Nozzle 76 Pilot Port 77 Main Port 78 Top Hat Port 80 Acoustic damper 81 First Acoustic Cover 82 Second Acoustic Cover 83 Third Acoustic Cover 90 First Bellmouth 90a First end surface 91 Mounting part 91a Bolt 92 First extension section 92a Inner surface 93 First Lip 93a First guide surface 100 Annular Bell Mouth 100a Annular guide surface 101 Gas Turbine 7 Support material 200 First Bellmouth 210 Bell mouth division body 211 Bellmouth first division 212 Bellmouth second division 220 Part 1 222 Fixed hole 224 Reamer bolt hole 226 Through hole 230 Second part 232 Occlusion 234 Information Department 235 First guide surface 240 Fixtures 242 Reamer bolt 243 Shaft 244 Threaded part 245 Head 246 Through Bolt 250 washer A Rotor axis O Combustor axis F Inlet channel D1 Insertion direction D2 Extraction direction C Virtual circle L reference line M first space E Second space S opening space θ1 First circumferential range θ2 Second circumferential range

Claims

1. a rotatable rotor; a casing that surrounds the rotor from the outer periphery and has an insertion hole that penetrates from the inside to the outside; a combustor inserted into the insertion hole from the outside of the rotor; Equipped with The combustor includes: an outer cylinder extending about the combustor axis and having a tip end protruding into the casing beyond the insertion hole; an inner cylinder disposed inside the outer cylinder and forming an annular introduction flow passage between the inner cylinder and the outer cylinder, the introduction flow passage opening toward the insertion direction of the combustor; and a first bell mouth that is provided on an inner surface of the casing so as to rise from a peripheral edge portion of the insertion hole in the insertion direction, extends over a first circumferential range that is a part of the circumferential range of the combustor axis, and has a first guide surface that guides air to the introduction flow path; a second bell mouth provided at a tip end of the outer cylinder, extending over a second circumferential range excluding the first circumferential range in the circumferential range, and including a second guide surface that guides air to the introduction flow path; a gas turbine in which the first guide surface and the second guide surface are connected to each other in the circumferential direction to form an annular guide surface.

2. The insertion hole, as viewed from the insertion direction, a first space that is a space within an imaginary circle centered on the combustor axis; a second space formed by extending a portion of the imaginary circle in the second circumferential direction outward in the radial direction of the rotor; Including, the outer cylinder has an outer diameter corresponding to the imaginary circle and is disposed within the first space as viewed from the insertion direction, The gas turbine according to claim 1 , wherein the second bell mouth is located within the second space when viewed from the insertion direction.

3. 3. The gas turbine according to claim 2, further comprising: an acoustic damper that is provided in the second circumferential range on an outer circumferential surface of the outer casing, that protrudes radially outward beyond the first bell mouth in the combustor axis direction, and that is located within the second space as viewed from the insertion direction.

4. The second bell mouth is a second extension portion that is integrally formed with the outer cylinder and protrudes from a tip of the outer cylinder in the insertion direction; a second lip that extends from a tip of the second extension portion radially outward in the combustor axis direction and forms the second guide surface; and The gas turbine according to claim 3 , wherein at least a portion of the acoustic damper is provided on an outer circumferential surface of the second extension portion.

5. The first bell mouth is an attachment portion detachably fixed to a peripheral portion of the insertion hole on the inner surface of the casing; a first extending portion protruding from the mounting portion in the insertion direction; a first lip that extends from a tip of the first extension portion toward an outer side in a radial direction of the combustor axis and forms the first guide surface; A gas turbine according to any one of claims 1 to 4, comprising:

6. the first bell mouth and the second bell mouth have end faces in the circumferential direction opposed to each other with a gap therebetween, The gas turbine according to any one of claims 1 to 4, wherein the gap extends obliquely with respect to a radial direction of the combustor axis when viewed from the insertion direction.

7. The gas turbine according to any one of claims 1 to 4, wherein the first bell mouth has a plurality of bell mouth segments that are arranged side by side in the circumferential direction and that are separable from one another.

8. The bellmouth segment is a first portion extending in a radial direction of the combustor axis in contact with the peripheral edge portion; a second portion disposed spaced apart from the first portion in the insertion direction and extending in the radial direction; a blocking portion connecting the first portion and the second portion so as to block an end portion of the first portion and the second portion radially outward from the combustor axis; a guide portion extending in the insertion direction from an end of the second portion radially inward in the combustor axis direction, the guide portion having the first guide surface at an end in the insertion direction, The gas turbine according to claim 7 , wherein the first portion, the second portion, and the closing portion define an open space that opens toward the inside in the radial direction.

9. the first bell mouth further has a plurality of fasteners that are fixed to the casing, the first bell mouth is formed with a plurality of fixing holes through which the fixing devices can be inserted, the fixing tool is inserted through at least one of the plurality of fixing holes with a first gap between the fixing tool and the fixing tool; 8. The gas turbine according to claim 7, wherein the fastener is inserted through at least one of the plurality of fixing holes with a second gap between the fastener and at least one of the fixing holes being larger than the first gap.

10. The plurality of fixing holes are arranged side by side in the circumferential direction, 10. The gas turbine according to claim 9, wherein the fixing holes through which the fixing devices are inserted with the first gaps formed are arranged at locations among the plurality of fixing holes arranged in the circumferential direction, excluding both ends in the circumferential direction.

11. an outer cylinder that extends about the combustor axis, has an insertion hole that penetrates from the inside to the outside of the casing, and is inserted from the outside into the casing, with a tip end that protrudes into the casing beyond the insertion hole; an inner cylinder disposed inside the outer cylinder and forming, between the inner cylinder and the outer cylinder, an annular introduction flow path that opens toward an insertion direction, which is a direction in which the outer cylinder is inserted into the casing; a first bell mouth that is provided on an inner surface of the casing so as to rise from a peripheral edge portion of the insertion hole in the insertion direction, extends over a first circumferential range that is a part of the circumferential range of the combustor axis, and has a first guide surface that guides air to the introduction flow path; a second bell mouth provided at a tip end of the outer cylinder, extending over a second circumferential range excluding the first circumferential range in the circumferential range, and including a second guide surface that guides air to the introduction flow path; Equipped with The combustor has an annular guide surface formed by the first guide surface and the second guide surface being connected to each other in the circumferential direction.

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