Gas turbine engine

Abstract

To improve containment performance without increasing a weight.SOLUTION: A gas turbine engine 100 comprises: a turbine casing 51; an exhaust casing 52; a metal-made heat insulation shield 80 attached to an internal peripheral face of the turbine casing 51; and a connecting part 90 for connecting the turbine casing 51 and the exhaust casing 52. The turbine casing 51 has: a main body part 51a; and a salient part 51b salient toward an axial line from an internal peripheral face 51a1 of the main body part 51a, and extending toward the exhaust casing 52 along an axial line. The heat insulation shield 80 has a hook 81 locked to a tip part 51b1 of the salient part 51b at the exhaust casing 52 side. The tip part 51b1 of the salient part 51b at the exhaust casing 52 side is arranged in a position being inside of an end part 52a of the exhaust casing 52 at the turbine case 51 side in a radial direction RD, and being overlapped with the end part in an axial line direction AD.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to gas turbine engines. [Background technology]

[0002] Conventionally, gas turbine engines used in aircraft and the like are required to have containment performance that keeps rotors such as blades from flying out when they break. Patent Document 1 discloses that an oil tank that stores lubricating oil is installed on the outside of the fan case to prevent broken parts from flying out when fan blades arranged inside the fan case break. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-127732 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, the oil tank is disposed at an axial position corresponding to the fan blades, so the oil tank does not contribute to preventing broken parts from scattering to the outside when the high-pressure turbine and low-pressure turbine rotated by the combustion gas are damaged. The ability to prevent broken parts from scattering to the outside when the high-pressure turbine and low-pressure turbine are damaged depends on the strength of the outer case and inner case.

[0005] However, increasing the thickness of the outer case and the inner case to increase their strength results in increased weight, which, for example, leads to poor fuel economy in gas turbine engines used in aircraft. Furthermore, arranging a shatterproof ring in addition to the outer case and the inner case also results in increased weight.

[0006] The present disclosure has been made in consideration of the above circumstances, and has an object to provide a gas turbine engine that can improve containment performance, which prevents broken material from scattering to the outside in the event of damage to a turbine driven by combustion gas, without increasing weight. [Means for solving the problem]

[0007] In order to solve the above problems, a gas turbine engine according to one aspect of the present disclosure includes a compressor having a plurality of compressor blades rotating about an axis and compressing external air to generate compressed air, a combustor that burns the compressed air generated by the compressor together with fuel to generate combustion gas, a turbine having a plurality of turbine blades rotating about the axis and driven by the combustion gas generated by the combustor, a shaft that connects the compressor and the turbine and extends along the axis, a turbine casing that is formed in a cylindrical shape extending along the axis and is disposed on the outer periphery of the turbine with respect to the axis, The exhaust casing is provided with an exhaust casing formed in a cylindrical shape extending along the axis and directing combustion gas that has passed through the turbine to the outside, and a connecting portion that connects the turbine casing and the exhaust casing, wherein the turbine casing has a main body portion that forms the outer shell of the turbine casing, and a protrusion portion that protrudes from the inner surface of the main body portion toward the axis and extends along the axis toward the exhaust casing, and the tip portion of the protrusion portion on the exhaust casing side is positioned in contact with or close to the radially inner side perpendicular to the axis with respect to the end portion of the exhaust casing on the turbine casing side. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a gas turbine engine that can improve the containment performance, which prevents broken objects from scattering to the outside in the event of damage to a turbine driven by combustion gas, without increasing weight. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a longitudinal sectional view showing a gas turbine engine according to a first embodiment of the present disclosure. [Diagram 2] FIG. 2 is a partial enlarged view of part A of the gas turbine engine shown in FIG. [Diagram 3] FIG. 4 is a partial enlarged view of a gas turbine engine according to a second embodiment of the present disclosure. [Figure 4] FIG. 11 is a side view of a turbine casing of a gas turbine engine according to a third embodiment of the present disclosure, as viewed from the exhaust casing side. [Diagram 5] FIG. 11 is a partial enlarged view of a gas turbine engine according to a fourth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [First embodiment] A gas turbine engine 100 according to a first embodiment of the present disclosure will be described below with reference to the drawings. Fig. 1 is a vertical cross-sectional view showing the gas turbine engine 100 according to the first embodiment of the present disclosure. The gas turbine engine 100 of the present embodiment is used, for example, as a thrust generating device for an aircraft.

[0011] As shown in FIGS. 1 and 2, a gas turbine engine 100 includes a compressor 10, a combustor 20, a turbine 30, a supercharging fan 40, an inner casing 50, an outer casing 60, and a shaft 70.

[0012] The compressor 10 is a device that generates compressed air by compressing external air EA flowing in from the front in the aircraft's traveling direction. The compressor 10 has a plurality of rotor blades (compression rotor blades) 11 that rotate around an axis X and are connected to a shaft 70, and generates compressed air by passing the external air EA that has flowed in through the plurality of rotor blades 11.

[0013] The combustor 20 is a device that burns the compressed air generated by the compressor 10 together with fuel to generate high-temperature, high-pressure combustion gas CA. The combustor 20 supplies the high-temperature, high-pressure combustion gas CA to the turbine 30 to rotate the turbine 30 about the axis X. The combustors 20 are provided at multiple locations around the axis X.

[0014] The turbine 30 is a device driven by the combustion gas CA generated by the combustor 20. The turbine 30 has a high-pressure turbine 31 and a low-pressure turbine 32 arranged downstream of the high-pressure turbine 31 in the flow direction of the combustion gas CA. The high-pressure turbine 31 has a plurality of high-pressure turbine rotor blades 31a connected to a shaft 70. The low-pressure turbine 32 has a plurality of low-pressure turbine rotor blades 32a connected to the shaft 70.

[0015] The low-pressure turbine rotor blade 32a has a blade portion 32a1 and a platform portion 32a2 formed integrally with the blade portion 32a1. The blade portion 32a1 is connected to a disk 32a3 attached to a shaft 70 via the platform portion 32a2.

[0016] By introducing the combustion gas CA into the turbine 30, the multiple high-pressure turbine rotor blades 31a and the multiple low-pressure turbine rotor blades 32a rotate about the axis X. The driving force that rotates the high-pressure turbine rotor blades 31a and the low-pressure turbine rotor blades 32a about the axis X is transmitted to the compressor 10 via the shaft 70. The compressor 10 rotates the rotor blades 11 using the power obtained from the turbine 30 to generate compressed air.

[0017] The supercharging fan 40 is a device that supplies external air EA to both the internal space of the inner casing 50 and the space between the inner casing 50 and the outer casing 60 by rotating about the axis X. The supercharging fan 40 is connected to the turbine 30 via a shaft 70. The supercharging fan 40 is rotated about the axis X by being driven by the turbine 30, and guides the external air EA to the compressor 10.

[0018] Next, the structure of a portion that discharges the combustion gas CA that has passed through the low-pressure turbine 32 to the outside will be described with reference to Fig. 2. Fig. 2 is a partial enlarged view of portion A of the gas turbine engine 100 shown in Fig. 1. As shown in Fig. 2, the gas turbine engine 100 of this embodiment includes a turbine casing 51 that constitutes a part of the inner casing 50, an exhaust casing 52, a heat shield (heat shield) 80, and a connecting portion 90.

[0019] The turbine casing 51 is a structure formed in a cylindrical shape extending along the axis X and disposed on the outer periphery side of the turbine 30 with respect to the axis X. The turbine casing 51 is formed of a metal material such as a heat-resistant alloy. The turbine casing 51 has a main body 51a forming an outer shell of the turbine casing 51, a protruding portion 51b protruding inward from an inner circumferential surface 51a1 of the main body 51a toward the axis X, and a flange portion (first flange portion) 51c formed at an end portion on the exhaust casing 52 side. The turbine casing 51 is formed by integrally forming the main body 51a, the protruding portion 51b, and the flange portion 51c.

[0020] The protruding portion 51b is formed in a cylindrical shape around the axis X and is disposed along the inner circumferential surface 51a1 of the turbine casing 51. The protruding portion 51b has a tip portion 51b1 extending toward the exhaust casing 52 along an axial direction AD parallel to the axis X, and a connecting portion 51b2 connecting the inner circumferential surface 51a1 of the main body portion 51a of the turbine casing 51 and the tip portion 51b1. The connecting portion 51b2 is formed to extend inward from the inner circumferential surface 51a1 of the main body portion 51a.

[0021] The tip 51b1 of the protruding portion 51b is disposed at a position that is on the inside in the radial direction RD (the side closer to the axis X) of the end 52a of the exhaust casing 52 on the turbine casing 51 side. Moreover, the tip 51b1 of the protruding portion 51b is disposed at a position that overlaps with the end 52a of the exhaust casing 52 on the turbine casing 51 side in the axial direction AD. That is, the tip 51b1 of the protruding portion 51b is disposed at a position that transmits the impact of a collision to the end 52a of the exhaust casing 52 on the turbine casing 51 side when debris generated by damage (breakage) of the low-pressure turbine rotor blade 32a collides with the end 52a.

[0022] The tip 51b1 of the protrusion 51b is formed so that the thickness t1 in the radial direction RD is constant at each position in the axial direction AD from the position P1 of one end in the axial direction AD connected to the connecting portion 51b2 to the position P2 of the other end in the axial direction AD. The tip 51b1 is also formed so that the thickness t1 in the radial direction RD is constant at each position in the circumferential direction around the axis X. Here, "constant" includes not only those whose thickness is strictly consistent but also those whose thickness varies within a predetermined error range.

[0023] The flange portion 51c is formed at an end portion on the exhaust casing 52 side in the axial direction AD and protrudes outward in the radial direction RD beyond the main body portion 51a. The flange portion 51c is formed in an annular shape all around the axis X and has a contact surface (first contact surface) 51c1 perpendicular to the axial direction AD.

[0024] 2, the thickness in the radial direction RD of the main body 51a in the vicinity of the flange portion 51c is t2. The thickness in the radial direction RD of the tip portion 51b1 of the protrusion 51b is set to be ⅓ or more and ⅔ or less of the thickness in the radial direction RD of the main body 51a.

[0025] The exhaust casing 52 is a structure formed in a cylindrical shape extending along the axis X and directing the combustion gas CA that has passed through the turbine 30 to the outside. The exhaust casing 52 is formed of a metal material such as a heat-resistant alloy. The exhaust casing 52 has a main body portion 52b and a flange portion (second flange portion) 52c formed at an end portion on the turbine casing 51 side in the axial direction AD. The exhaust casing 52 is formed by integrally forming the main body portion 52b and the flange portion 52c.

[0026] The flange portion 52c is formed at an end portion on the turbine casing 51 side in the axial direction AD and protrudes outward in the radial direction RD beyond the main body portion 52b. The flange portion 52c is formed in an annular shape all around the axis X and has a contact surface (second contact surface) 52c1 perpendicular to the axial direction AD. The shaft 70 is formed to extend along the axis X and connects the compressor 10 and the turbine 30. The driving force of the turbine 30, which is rotated about the axis X by the combustion gas CA, is transmitted to the compressor 10 via the shaft 70.

[0027] The heat shield 80 is a structure formed in a cylindrical shape extending along the axis X and attached to the inner circumferential surface of the turbine casing 51. The heat shield 80 is a structure for suppressing the transfer of heat of the combustion gas CA to the turbine casing 51. The heat shield 80 is formed of a metal material such as a heat-resistant alloy.

[0028] The heat shield 80 has a hook 81 formed at an end portion on the exhaust casing 52 side in the axial direction AD. The heat shield 80 is disposed along the inner circumferential surface 51a1 of the turbine casing 51 by engaging the hook 81 with a tip portion 51b1 on the exhaust casing 52 side of the protrusion 51b.

[0029] 2, a hook 81 of a heat shield 80 is disposed between a tip 51b1 of the protruding portion 51b and an end 52a of the exhaust casing 52 on the turbine casing 51 side. The hook 81 may be disposed in a state of contact with the end 52a of the exhaust casing 52 on the turbine casing 51 side, or may be disposed in a state of closeness with a small gap provided along the radial direction RD between the hook 81 and the end 52a of the exhaust casing 52 on the turbine casing 51 side. Here, the closeness state refers to a state in which a gap is provided between the tip 51b1 and the end 52a so that the entire cross section of the position P1, which is the boundary of the connecting portion 51b2 of the tip 51b1, is not plastically deformed (fully plastic state) when the tip 51b1 is bent due to the impact of a broken piece of the low-pressure turbine rotor blade 32a colliding with the protruding portion 51b and the tip 51b1 comes into contact with the end 52a on the turbine casing 51 side.

[0030] The connecting portion 90 is a structure that connects the turbine casing 51 and the exhaust casing 52. The connecting portion 90 has a fastening bolt 91 and a fastening nut 92. The connecting portion 90 connects the flange portion 51c and the flange portion 52c with the contact surface 51c1 and the contact surface 52c1 in contact with each other.

[0031] Here, the reason why the protrusion 51b improves the containment performance that prevents broken objects from scattering to the outside when the turbine 30 driven by the combustion gas CA is damaged will be described. When the low-pressure turbine rotor blade 32a of the low-pressure turbine 32 shown in Fig. 1 is damaged (broken), broken objects smaller than the low-pressure turbine rotor blade 32a are scattered along the axial direction AD toward the downstream side in the flow direction of the combustion gas CA and toward the outer periphery side in the radial direction RD (the side moving away from the axis X along the radial direction RD).

[0032] The low-pressure turbine 32 is composed of a plurality of stages arranged in the axial direction AD, and each stage is configured such that a plurality of low-pressure turbine rotor blades 32a are arranged in a circle around the axis X with the shaft 70 at the center. If the low-pressure turbine rotor blade 32a arranged at the most downstream side in the flow direction of the combustion gas CA among the plurality of low-pressure turbine rotor blades 32a is damaged, there is a high possibility that the broken part included in the platform portion 32a2, which occupies a relatively larger proportion of the total weight of the low-pressure turbine rotor blade 32a than the blade portion 32a1, will collide with the protruding portion 51b. The turbine casing 51 and the exhaust casing 52 are connected by a connecting portion 90 in the vicinity of the protruding portion 51b.

[0033] Since the flange portion 51c and the flange portion 52c are connected by the connecting portion 90, and the rigidity against deformation in the radial direction RD is increased, the elastic deformation of the turbine casing 51 in the radial direction RD is hindered, and plastic strain occurs in the turbine casing 51 near the protruding portion 51b. If the impact that generates the plastic strain is not transmitted from the turbine casing 51 to other locations, the turbine casing 51 may be damaged by the plastic strain, and broken pieces of the low-pressure turbine rotor blades 32a may be scattered to the outside.

[0034] In order to ensure sufficient strength so that the turbine casing 51 is not damaged by plastic strain, it is effective to increase the thickness of the turbine casing 51, but this increases the weight of the turbine casing 51. In this embodiment, the tip 51b1 of the protrusion 51b is disposed at a position where it transmits the impact of the collision to the end 52a of the exhaust casing 52 on the turbine casing 51 side when debris generated by damage (breakage) of the low-pressure turbine rotor blades 32a collides with the turbine casing 51. Since the impact that generates plastic strain is transmitted from the turbine casing 51 to the exhaust casing 52, it is possible to improve the containment performance without increasing the weight of the gas turbine engine 100.

[0035] The actions and effects achieved by the gas turbine engine 100 of the present embodiment described above will be described below. According to the gas turbine engine 100 of this embodiment, the protruding portion 51b protruding from the inner peripheral surface 51a1 of the main body 51a forming the outer shell of the turbine casing 51 toward the axis X extends toward the exhaust casing 52 along the axis X. The heat shield 80 is attached to the inner peripheral surface 51a1 of the turbine casing 51 by a hook 81 engaged with a tip portion 51b1 of the protruding portion 51b on the exhaust casing 52 side. The tip portion 51b1 of the protruding portion 51b is disposed inward of the end portion 52a of the exhaust casing 52 on the turbine casing 51 side in the radial direction RD perpendicular to the axis X and overlaps with the end portion 52a in the axis X direction. When the low-pressure turbine rotor blade 32a is broken and the broken object collides with the protruding portion 51b, the impact caused by the collision of the broken object with the protruding portion 51b is transmitted from the tip portion 51b1 of the protruding portion 51b to the end portion 52a of the exhaust casing 52 on the turbine casing 51 side.

[0036] According to the gas turbine engine 100 of this embodiment, the impact caused by the collision of the broken part of the low-pressure turbine rotor blade 32a with the protruding part 51b is transmitted to the exhaust casing 52. Therefore, the impact load transmitted to the main body part 51a is reduced compared to the case where the impact is not transmitted to the exhaust casing 52, and the plastic strain generated in the main body part 51a is reduced. This prevents the broken part of the low-pressure turbine rotor blade 32a from destroying the turbine casing 51 and scattering to the outside, improving the containment performance. In addition, the containment performance is improved by devising the shape of the tip of the protruding part 51b for engaging the hook 81 of the heat shield 80. Therefore, the containment performance can be improved without increasing the weight by thickening the entire turbine casing 51, for example.

[0037] According to the gas turbine engine 100 of this embodiment, the thickness t1 in the radial direction RD of the tip portion 51b1 is ⅓ or more of the thickness t2 in the radial direction RD of the main body portion 51a in the vicinity of the flange portion 51c, so that the strength of the tip portion 51b1 can be sufficiently ensured. Also, the thickness t1 in the radial direction RD of the tip portion 51b1 is ⅔ or less of the thickness t2 in the axial direction AD of the flange portion 51c, so that the weight of the turbine casing 51 is not excessively increased.

[0038] Second Embodiment Next, a gas turbine engine 100A according to a second embodiment of the present disclosure will be described with reference to the drawings. This embodiment is a modified example of the first embodiment, and is the same as the first embodiment except where specifically described below, and therefore the description below will be omitted.

[0039] In the gas turbine engine 100 of the first embodiment, the thickness t1 in the radial direction RD of the tip portion 51b1 of the protrusion 51b is constant at each position along the axis X. In contrast, in the gas turbine engine 100A of the present embodiment, the thickness t1 in the radial direction RD of the tip portion 51b1 of the protrusion 51b decreases toward the exhaust casing 52 along the axis X.

[0040] 3 is a partially enlarged view of a gas turbine engine according to a second embodiment of the present disclosure. As shown in FIG. 3, a tip end 51b1 of the protruding portion 51b is formed such that a thickness t1 in a radial direction RD decreases from a position P1 of one end in the axial direction AD connected to the connecting portion 51b2 to a position P2 of the other end in the axial direction AD as the thickness approaches the exhaust casing 52 along the axis X.

[0041] According to the gas turbine engine 100A of the present embodiment, the thickness t1 in the radial direction RD of the tip 51b1 of the protrusion 51b decreases as it approaches the exhaust casing 52 along the axis X, and increases as it moves away from the exhaust casing 52 along the axial direction AD. Therefore, the thickness t1 in the radial direction RD of the tip 51b1 of the low-pressure turbine rotor blade 32a in the region likely to be hit by debris can be made thicker, thereby preventing the protrusion 51b from being damaged by the impact of the debris.

[0042] Third Embodiment Next, a gas turbine engine 100B according to a third embodiment of the present disclosure will be described with reference to the drawings. This embodiment is a modified example of the first embodiment, and is the same as the first embodiment except where specifically described below, and therefore the description below will be omitted.

[0043] In the gas turbine engine 100 of the first embodiment, the thickness t1 in the radial direction RD of the tip end 51b1 of the protrusion 51b is constant at each position along the axis X and is also constant at each position in the circumferential direction CD about the axis X. In contrast, in the gas turbine engine 100B of the present embodiment, the thickness t1 in the radial direction RD of the tip end 51b1 of the protrusion 51b changes periodically along the circumferential direction CD about the axis X.

[0044] Fig. 4 is a side view of the turbine casing 51 of a gas turbine engine 100B according to a third embodiment of the present disclosure, viewed from the exhaust casing 52 side. In Fig. 4, the heat shield 80 attached to the protruding portion 51b is omitted. As shown in Fig. 4, the tip portion 51b1 of the protruding portion 51b is formed so that the thickness t1 in the radial direction RD changes periodically along the circumferential direction CD about the axis line X.

[0045] The spacing W1 in the circumferential direction CD of the apex S, where the thickness t1 in the radial direction RD of the tip portion 51b1 is the thickest, is set to less than 2% of the outer diameter D1 (see Figure 1) relative to the axis X of the main body portion 51a at the position in the axial direction AD where the protrusion 51b is located.

[0046] According to the gas turbine engine 100B of this embodiment, the spacing W1 in the circumferential direction CD of the tops S is set to less than 2% of the outer diameter D1 relative to the axis X of the main body 51a. This appropriately prevents a broken piece of the low-pressure turbine blade 32a having a volume equal to or greater than a certain level that could destroy the main body 51a from colliding only with the valley portion V where the thickness t1 of the tip portion 51b1 in the radial direction RD is the thinnest, thereby preventing the protrusions 51b from being easily damaged.

[0047] 4, through holes 51b1A are formed in the circumferential direction CD at the positions of the multiple apexes S where the thickness t1 in the radial direction RD of the tip portion 51b1 is the thickest, penetrating along the axis X. According to the gas turbine engine 100B of this embodiment, the through holes 51b1A are formed in the positions of the multiple apexes S where the thickness t1 in the radial direction RD of the tip portion 51b1 is the thickest, so that it is possible to reduce the weight of the tip portion 51b1 while maintaining the strength of the tip portion 51b1.

[0048] This embodiment is a modification of the first embodiment, but may be a modification of the second embodiment. In this embodiment, which is a modification of the first embodiment, the tip portion 51b1 is formed so that the thickness t1 in the radial direction RD is constant at each position in the axial direction AD, and the thickness t1 in the radial direction RD changes periodically along the circumferential direction CD. On the other hand, in the case of a modification of the second embodiment, the tip portion 51b1 is formed so that the thickness t1 in the radial direction RD decreases as it approaches the exhaust casing 52 along the axial direction AD, and the thickness t1 in the radial direction RD changes periodically along the circumferential direction CD.

[0049] [Fourth embodiment] Next, a gas turbine engine 100C according to a fourth embodiment of the present disclosure will be described with reference to the drawings. This embodiment is a modified example of the first embodiment, and is the same as the first embodiment except where specifically described below, and therefore the description below will be omitted.

[0050] In the gas turbine engine 100 of the first embodiment, the tip portion 51b1 is disposed inward in the radial direction RD perpendicular to the axis X with respect to the end portion 52a of the exhaust casing 52 on the turbine casing 51 side at each position in the circumferential direction CD and overlaps with the end portion 52a in the axial direction AD. In contrast, in the gas turbine engine 100C of the present embodiment, the tip portion 51b1 has first portions 51b1B and second portions 51b1C alternately disposed along the circumferential direction CD.

[0051] Fig. 5 is a partial enlarged view of a gas turbine engine 100C according to a fourth embodiment of the present disclosure. As shown in Fig. 5, a tip portion 51b1 has a first portion 51b1B and a second portion 51b1C arranged alternately along a circumferential direction CD about the axis X. The first portion 51b1B is a portion arranged in a position that is on the inside of an end portion 52a of the exhaust casing 52 on the turbine casing 51 side in a radial direction RD perpendicular to the axis X and overlaps with the end portion 52a in the axial direction AD.

[0052] The second portion 51b1C is a portion that is disposed inward in a radial direction RD perpendicular to the axis X with respect to an end portion 52a of the exhaust casing 52 on the turbine casing 51 side, and at a position that does not overlap with the end portion 52a in the axial direction AD. As shown in Fig. 5, the hook 81 of the heat shield 80 is not engaged with the first portion 51b1B of the tip portion 51b1, but is engaged only with the second portion 51b1C.

[0053] According to the gas turbine engine 100C of this embodiment, the impact caused by the broken part of the low-pressure turbine blade 32a colliding with the protruding part 51b is transmitted to the exhaust casing 52 by the first part 51b1B of the tip part 51b1, so that the breakage of the protruding part 51b and the scattering of the broken part of the low-pressure turbine blade 32a to the outside are suppressed compared to the case where the impact is not transmitted to the exhaust casing 52, thereby improving containment performance.

[0054] Furthermore, the second portion 51b1C of the tip portion 51b1 positions the heat shield 80 along the inner circumferential surface 51a1 of the turbine casing 51. Therefore, the heat shield 80 can be easily attached to the inner circumferential surface 51a1 of the turbine casing 51 without positioning the hook 81 of the heat shield 80 between the first portion 51b1B of the tip portion 51b1 and the end portion 52a of the exhaust casing 52 on the turbine casing 51 side.

[0055] The gas turbine engine according to each of the above-described embodiments can be understood, for example, as follows. A gas turbine engine (100) according to a first aspect of the present disclosure includes a compressor (10) having a plurality of compression rotor blades (11) rotating about an axis (X) and compressing external air to generate compressed air, a combustor (20) burning the compressed air generated by the compressor together with fuel to generate combustion gas, a turbine (30) having a plurality of turbine rotor blades (31 a, 32 a) rotating about the axis and driven by the combustion gas generated by the combustor, a shaft (70) connecting the compressor and the turbine and extending along the axis, and a turbine casing formed in a cylindrical shape extending along the axis and disposed on the outer periphery of the turbine with respect to the axis. (51), an exhaust casing (52) formed in a cylindrical shape extending along the axis and directing combustion gas that has passed through the turbine to the outside, and a connecting portion (90) connecting the turbine casing and the exhaust casing, wherein the turbine casing has a main body portion (51a) forming the outer shell of the turbine casing, and a protrusion portion (51b) protruding from an inner surface of the main body portion toward the axis and extending along the axis toward the exhaust casing, and a tip portion of the protrusion on the exhaust casing side is arranged in contact with or close to the radially inner side perpendicular to the axis with respect to the turbine casing side end of the exhaust casing.

[0056] In a gas turbine engine according to a first aspect of the present disclosure, a protrusion protruding from an inner circumferential surface of a main body forming an outer shell of a turbine casing toward an axis extends along the axis toward an exhaust casing. A tip of the protrusion is disposed in contact with or in close proximity to an end of the exhaust casing on the turbine casing side, on the radially inner side perpendicular to the axis. When a turbine blade is broken and the broken object collides with the protrusion, the impact caused by the collision of the broken object with the protrusion is transmitted from the tip of the protrusion to the end of the exhaust casing on the turbine casing side.

[0057] According to the gas turbine engine of the first aspect of the present disclosure, the impact caused by the collision of the broken part of the turbine rotor blade with the protruding part is transmitted to the exhaust casing, so the impact load transmitted to the main body is reduced and the plastic strain generated in the main body is reduced compared to when the impact is not transmitted to the exhaust casing. This prevents the broken part of the turbine rotor blade from destroying the turbine casing and scattering to the outside, improving the containment performance. In addition, the containment performance can be improved by devising the shape of the tip of the protruding part without increasing the weight by thickening the entire turbine casing, for example.

[0058] A gas turbine engine according to a second aspect of the present disclosure is the first aspect, further comprising the following configuration: the protrusion has the tip portion and a connection portion (51b2) that connects an inner circumferential surface of the main body and the tip portion and extends inward along the radial direction, and the tip portion is formed such that the radial thickness is constant at each position in the axial direction.

[0059] According to the gas turbine engine according to the second aspect of the present disclosure, the radial thickness of the tip of the protrusion is constant at each position along the axis, thereby making the strength of the tip at each axial position uniform, thereby preventing the protrusion from being damaged by the impact of a breaking object.

[0060] A gas turbine engine according to a third aspect of the present disclosure is the first aspect, further comprising the following configuration: the protrusion has the tip portion and a connection portion that connects an inner circumferential surface of the main body and the tip portion and extends inward along the radial direction, and the tip portion is formed such that the radial thickness decreases toward the exhaust casing along the axis.

[0061] According to the gas turbine engine according to the third aspect of the present disclosure, the radial thickness of the tip of the protrusion decreases as it approaches the exhaust casing along the axis and increases as it moves away from the exhaust casing in the axial direction. Therefore, the radial thickness of the tip of the turbine rotor blade in the region where it is likely to collide with broken debris is increased, and the protrusion can be prevented from being damaged by the impact of broken debris.

[0062] The gas turbine according to a fourth aspect of the present disclosure is the first aspect, further comprising the following configuration: the protruding portion is formed in a cylindrical shape about the axis, and has the tip portion and a connection portion that connects the inner circumferential surface of the main body and the tip portion and extends inward along the radial direction, and the tip portion is formed such that the radial thickness changes periodically along the circumferential direction about the axis.

[0063] According to a gas turbine engine according to a fourth aspect of the present disclosure, the tip portion is formed such that the radial thickness changes periodically along the circumferential direction about the axis, and therefore, compared to a case in which the radial thickness of the tip portion is made thick over the entire circumferential area, it is possible to suppress an increase in the weight of the turbine casing while increasing the strength of the tip portion.

[0064] The gas turbine according to a fifth aspect of the present disclosure is the fourth aspect, further comprising the following configuration: A circumferential interval (W1) of a top portion where the radial thickness of the tip portion is the thickest is set to less than 2% of an outer diameter of the main body portion relative to the axis at a position in the axial direction where the protrusion is disposed.

[0065] In the gas turbine engine according to the fifth aspect of the present disclosure, the circumferential spacing of the tops is set to less than 2% of the outer diameter relative to the axis of the main body, thereby appropriately preventing turbine blade debris having a volume equal to or greater than a certain level that could destroy the main body from colliding only with the valley portion where the radial thickness of the tip is the thinnest, thereby easily damaging the protrusion.

[0066] A gas turbine according to a sixth aspect of the present disclosure is the fourth aspect, further comprising the following configuration: the turbine casing has a first flange portion (51c) formed at an end portion on the exhaust casing side in the axial direction and having a first contact surface perpendicular to the axis, the exhaust casing has a second flange portion (52c) formed at an end portion on the turbine casing side in the axial direction and having a second contact surface perpendicular to the axis, the connecting portion connects the first flange portion and the second flange portion with the first contact surface and the second contact surface in contact with each other, and the radial thickness of the tip portion is set to be equal to or greater than ⅓ and equal to or less than ⅔ of the radial thickness of the main body portion.

[0067] According to the gas turbine engine of the sixth aspect of the present disclosure, the radial thickness of the tip portion is ⅓ or more of the radial thickness of the main body, so that the strength of the tip portion can be sufficiently ensured. Also, the radial thickness of the tip portion is ⅔ or less of the radial thickness of the main body, so that the weight of the turbine casing is not excessively increased.

[0068] A gas turbine engine according to a seventh aspect of the present disclosure is the fourth aspect, further comprising the following configuration: That is, through holes (51b1A) penetrating along the axis are formed at a plurality of positions in the circumferential direction where the radial thickness of the tip portion is the thickest.

[0069] According to the gas turbine engine according to the seventh aspect of the present disclosure, through holes are formed at multiple positions where the radial thickness of the tip portion is at its thickest, thereby making it possible to reduce the weight of the tip portion while maintaining its strength.

[0070] The gas turbine engine according to an eighth aspect of the present disclosure is the gas turbine engine of any one of the first to third aspects, further comprising the following configuration: A metal heat shield (80) formed in a cylindrical shape extending along the axis and attached to an inner circumferential surface of the turbine casing, the heat shield having a hook (81) formed at an end portion on the exhaust casing side and engaged with a tip portion (51b1) of the protruding portion on the exhaust casing side.

[0071] According to the gas turbine engine of the eighth aspect of the present disclosure, a protrusion is used to engage a heat shield that suppresses the transfer of heat from the combustion gas to the turbine casing, so that the impact caused by a broken object colliding with the protrusion is transferred from the tip of the protrusion to the end of the exhaust casing on the turbine casing side, thereby improving containment performance.

[0072] A gas turbine engine according to a ninth aspect of the present disclosure is the eighth aspect, further including the following configuration: That is, the tip portion has a first portion (51b1B) that is located on the inside in a radial direction perpendicular to the axis with respect to an end portion of the exhaust casing on the turbine casing side and is arranged at a position overlapping in the axial direction, and a second portion (51b1C) that is located on the inside in a radial direction perpendicular to the axis with respect to an end portion of the exhaust casing on the turbine casing side and is arranged at a position not overlapping in the axial direction, the first portion and the second portion are arranged alternately along the circumferential direction, and the hook is engaged with the second portion.

[0073] According to the gas turbine engine of the ninth aspect of the present disclosure, the first part of the tip transmits the impact caused by the collision of the broken part of the turbine blade with the protruding part to the exhaust casing, which suppresses the broken part of the turbine blade from scattering to the outside due to the breakage of the protruding part, compared to the case where the impact is not transmitted to the exhaust casing, thereby improving the containment performance. Also, the second part of the tip positions the heat shield along the inner peripheral surface of the turbine casing. Therefore, the heat shield can be easily attached to the inner peripheral surface of the turbine casing without arranging the hook of the heat shield between the first part of the tip and the end of the exhaust casing on the turbine casing side. [Explanation of symbols]

[0074] 10 Compressor 20 Combustor 30 Turbine 31 High Pressure Turbine 31a High pressure turbine blade 32 Low Pressure Turbine 32a Low pressure turbine blade 32a1 wing section 32a2 Platform section 32a3 disk 40 Supercharged fan 50 Inner casing 51 Turbine casing 51a Main body 51a1 Inner surface 51b Protrusion 51b1 Tip 51b1A Through hole 51b1B Part 1 51b1C Part 2 51b2 Connection 51c Flange part 51c1 Contact surface 52 Exhaust casing 52a end 52b Main body 52c Flange 52c1 Contact surface 60 Outer casing 70 Shaft 80 Heat Shield 81 Hook 90 Connection part 91 Fastening bolt 92 Fastening nut 100, 100A, 100B, 100C Gas Turbine Engine AD Axial direction CA Combustion Gas CD circumferential direction D1 Outer diameter EA External Air RD radial direction S top V Tanibe X axis t1,t2 thickness

Claims

1. a compressor having a plurality of compression rotor blades that rotate around an axis and compresses external air to generate compressed air; a combustor that burns the compressed air generated by the compressor together with fuel to generate combustion gas; a turbine having a plurality of turbine blades rotating about the axis and driven by combustion gas generated by the combustor; a shaft connecting the compressor and the turbine and extending along the axis; a turbine casing formed in a cylindrical shape extending along the axis and disposed on an outer circumferential side of the turbine with respect to the axis; an exhaust casing that is formed in a cylindrical shape extending along the axis and that guides the combustion gas that has passed through the turbine to the outside; a connection portion that connects the turbine casing and the exhaust casing, The turbine casing comprises: a main body portion forming an outer shell of the turbine casing; a protrusion protruding from an inner circumferential surface of the main body toward the axis and extending along the axis toward the exhaust casing, A gas turbine engine, wherein a tip end of the protrusion on the exhaust casing side is arranged in contact with or in close proximity to an end of the exhaust casing on the turbine casing side, on the radially inner side in a direction perpendicular to the axis.

2. The protrusion has the tip portion and a connection portion that connects an inner circumferential surface of the main body and the tip portion and extends inward along the radial direction, 2. The gas turbine engine according to claim 1, wherein the tip portion is formed so that the radial thickness is constant at each position along the axis.

3. The protrusion has the tip portion and a connection portion that connects an inner circumferential surface of the main body and the tip portion and extends inward along the radial direction, 2. The gas turbine engine of claim 1, wherein said tip portion is formed such that said radial thickness decreases approaching said exhaust casing along said axis.

4. the protrusion is formed in a cylindrical shape around the axis, and has the tip portion and a connection portion that connects the inner circumferential surface of the main body and the tip portion and extends inward along the radial direction, 4. The gas turbine engine according to claim 1, wherein the tip portion is formed such that the radial thickness thereof changes periodically along a circumferential direction about the axis.

5. 5. The gas turbine engine according to claim 4, wherein the circumferential spacing of the apex portions where the radial thickness of the tip portion is greatest is set to less than 2% of an outer diameter of the main body portion relative to the axis at a position along the axis where the protrusion is disposed.

6. the turbine casing has a first flange portion formed at an end portion of the turbine casing on the exhaust casing side in a direction along the axis and having a first contact surface perpendicular to the axis, the exhaust casing has a second flange portion formed at an end portion of the exhaust casing on the turbine casing side in a direction along the axis and having a second contact surface perpendicular to the axis, the connecting portion connects the first flange portion and the second flange portion with the first contact surface and the second contact surface in contact with each other, 5. The gas turbine engine according to claim 4, wherein the radial thickness of the tip portion is set to be equal to or greater than 1 / 3 and equal to or less than 2 / 3 of the radial thickness of the main body portion.

7. 5. The gas turbine engine according to claim 4, wherein through holes are formed in a plurality of positions in the circumferential direction where the radial thickness of the tip portion is greatest, the through holes penetrating the tip portion along the axis.

8. a metallic heat shield formed in a cylindrical shape extending along the axis and attached to an inner circumferential surface of the turbine casing, 4. The gas turbine engine according to claim 1, wherein the heat shield is formed at an end portion on the exhaust casing side and has a hook that is engaged with a tip portion of the protrusion on the exhaust casing side.

9. The tip portion is a first portion disposed at a position that is radially inward with respect to an end portion of the exhaust casing on the turbine casing side and that overlaps with the end portion in a direction along the axis; a second portion disposed in a position that is radially inward with respect to an end portion of the exhaust casing on the turbine casing side and does not overlap with the end portion in a direction along the axis, The first portions and the second portions are alternately arranged along a circumferential direction around the axis, The gas turbine engine of claim 8 , wherein said hook is anchored to said second portion.

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