Turbine interstage support structure and gas turbine engine

Abstract

The present invention discloses a turbine interstage support structure and a gas turbine engine. The loads of the front fulcrum and the rear fulcrum are respectively transmitted to the interstage bearing seat through the front fulcrum bearing outer ring and the rear fulcrum bearing outer ring, and then transmitted to the elastic bracket through the second connecting member, and then transmitted to the interstage support guide through the first connecting member, and finally transmitted to the turbine casing. The entire support structure is compact, and the axial and radial dimensions are small, which can not only well meet the restriction requirements of the radial dimension of the turbine interstage, but also help to reduce the axial dimension and weight of the engine, thereby reducing the required lubricating oil cooling flow. A heat insulation cavity is arranged below the gas flow channel, and a heat insulation member is installed in the heat insulation cavity, which can effectively isolate the high-temperature gas in the gas flow channel from heat transfer and heat radiation to the support structure, thereby improving the stability, reliability and life of the dynamic characteristics of the support structure, and the lubricating oil is not easy to coke, reducing the risk of bearing lubrication nozzle blockage and lubricating oil failure.

Description

Technical Field

[0001] The present invention relates to the technical field of gas turbines, and in particular to a turbine interstage support structure. In addition, the present invention also relates to a gas turbine engine using the turbine interstage support structure. Background Art

[0002] With the development of aircraft engine technology, the configuration of gas turbine engines (especially small and medium-sized gas turbine engines) almost all include an interstage support structure 20 between the gas turbine 24 and the power turbine 21 (or between the high-pressure turbine and the low-pressure turbine). The temperature rise of the combustion chamber 23 of most gas turbine engines exceeds 1000°C, resulting in a gas temperature of about 900°C or even higher in the turbine interstage flow path. Figure 1 As shown. Due to the radial dimension limitation of the turbine stages of small and medium-sized gas turbine engines, the axial dimension of the interstage support structure 20 is relatively long, resulting in a larger axial dimension and heavier weight of the engine, which requires a larger lubricating oil cooling flow rate. However, the existing interstage support structure 20 does not adopt a cooling structure and a thermal isolation structure. The interstage support structure 20 is significantly affected by high-temperature combustion gas. The change in combustion gas temperature has a significant impact on the dynamic characteristics of the support structure, the lubricating oil cooling and lubrication flow rate, and the stability, reliability and life of the support structure. It is also easy to cause lubricating oil coking, which poses the risk of clogging the bearing lubrication nozzle and lubricating oil failure. Summary of the invention

[0003] The present invention provides a turbine interstage support structure and a gas turbine engine to solve the technical problems of poor structural stability and easy coking of lubricating oil in the existing bearing support structure under the influence of high-temperature combustion gas.

[0004] According to one aspect of the present invention, there is provided a turbine interstage support structure, comprising an interstage support guide, a heat insulating member, an interstage bearing seat, an elastic support, a first connecting member, a second connecting member, a front pivot bearing outer ring and a rear pivot bearing outer ring, wherein the upper end of the interstage support guide is connected to the turbine casing, and the lower end is connected to the upper end of the elastic support via a first connecting member, and the lower end of the elastic support is connected to the rear end of the interstage bearing seat via a second connecting member, the front pivot bearing outer ring and the rear pivot bearing outer ring are both mounted on the bottom of the interstage bearing seat, the front pivot bearing outer ring is a gas turbine rotor fulcrum, and the rear pivot bearing outer ring is a power turbine rotor fulcrum, and an insulation cavity is provided below the gas flow channel in the interstage support guide, the insulation member is mounted in the insulation cavity and is used to isolate the high-temperature gas in the gas flow channel from heat transfer and heat radiation to the support structure.

[0005] Furthermore, the interstage support guide includes an integrally cast mounting edge, a gas flow channel outer casing, guide vanes, a gas flow channel inner casing and a backward-bending elastic casing, the mounting edge is connected to the gas flow channel outer casing and is installed on the turbine casing, a gas flow channel is formed between the gas flow channel outer casing and the gas flow channel inner casing, the guide vanes are respectively connected to the gas flow channel outer casing and the gas flow channel inner casing, the backward-bending elastic casing is connected to the gas flow channel inner casing and an annular heat-insulating cavity is formed therebetween.

[0006] Furthermore, it also includes a front baffle ring, a front outer ring of the bearing seat, a front inner ring of the bearing seat and a front baffle plate, the front outer ring of the bearing seat and the front inner ring of the bearing seat are respectively connected to the front end of the interstage bearing seat, and the front outer ring of the bearing seat is respectively connected to the front baffle ring and the front baffle plate, and the front inner ring of the bearing seat is connected to the front baffle plate, and a first cooling cavity is formed by the front baffle ring, the front outer ring of the bearing seat, the front inner ring of the bearing seat, the front baffle plate, the rear bent elastic casing and the elastic bracket, and the upper part of the interstage bearing seat is located in the first cooling cavity, and the interstage support guide and the heat insulation member are provided with a lubricating oil inlet channel, and the lubricating oil inlet pipe passes through the lubricating oil inlet channel and is installed on the upper part of the interstage bearing seat, and the first cooling cavity is provided with an axial cooling air flow channel for introducing high-pressure cooling air from the compressor to efficiently cool the rear bent elastic casing and the interstage bearing seat.

[0007] Furthermore, a plurality of first pre-swirl holes are circumferentially provided on the front baffle ring for introducing high-pressure cooling air from the rear end of the compressor and performing pre-swirl expansion and acceleration on the high-pressure cooling air; a plurality of first air flow holes are circumferentially provided on the rearward-bending elastic casing; a second air flow hole is provided on the elastic bracket at a corresponding position of the first air flow hole; the high-pressure cooling air is introduced into the first cooling cavity through the first pre-swirl holes, and flows out of the first cooling cavity through the first air flow hole and the second air flow hole.

[0008] Furthermore, a sealing retaining ring is provided between the front retaining ring and the rearward-bending elastic casing, and a W sealing ring is provided between the elastic bracket and the upper part of the interstage bearing seat.

[0009] Furthermore, it also includes a rear guide plate and a rear baffle, the rear guide plate is connected to the elastic bracket and the rear-bent elastic casing through a first connecting piece, the rear baffle is installed on the elastic bracket, the rear guide plate, the rear baffle and the elastic bracket together form a second cooling cavity, a gap is left between the rear guide plate and the rear baffle, a plurality of second pre-swirl holes are opened in the circumferential direction along the upper edge of the rear guide plate, the second pre-swirl holes are connected with the second air flow holes, the high-pressure cooling air in the first cooling cavity flows into the second cooling cavity through the second pre-swirl holes, and the high-pressure cooling air cools the rear guide plate and then flows out from the gap between the rear guide plate and the rear baffle.

[0010] Furthermore, the angle between the opening direction of the first pre-rotating hole and / or the second pre-rotating hole and the cross-sectional plane is 15° to 50°.

[0011] Furthermore, a main lubricating oil flow channel, a front lubricating oil flow channel and a rear lubricating oil nozzle are provided in the interstage bearing seat. The front lubricating oil flow channel and the rear lubricating oil nozzle are both connected to the main lubricating oil flow channel. The front lubricating oil flow channel is used to form a squeeze oil film damper structure for the gas turbine rotor fulcrum, and the rear lubricating oil nozzle is used to lubricate the power turbine rotor fulcrum.

[0012] Furthermore, the outlet of the rear lubricating oil nozzle is aligned with the power turbine rotor fulcrum, a gap is left between the front fulcrum bearing outer ring and the interstage bearing seat, and the outlet of the front lubricating oil flow channel connects the gap between the two to form a squeeze film damper.

[0013] In addition, the present invention also provides a gas turbine engine, which adopts the turbine interstage support structure as described above.

[0014] The present invention has the following effects:

[0015] In the turbine interstage support structure of the present invention, the loads of the gas turbine rotor fulcrum and the power turbine rotor fulcrum are respectively transmitted to the interstage bearing seat through the front fulcrum bearing outer ring and the rear fulcrum bearing outer ring, and then transmitted to the elastic bracket through the second connecting member, and then transmitted to the interstage support guide through the first connecting member, and finally transmitted to the turbine casing. The entire support structure is compact, and the axial and radial dimensions are small, which can not only well meet the restriction requirements of the radial dimension of the turbine interstage, but also help to reduce the axial dimension and weight of the engine, thereby reducing the required lubricating oil cooling flow. More importantly, a heat insulation cavity is provided below the gas flow channel, and a heat insulation member is installed in the heat insulation cavity. A pre-rotation cooling structure is provided below the heat insulation cavity, which can effectively isolate the high-temperature gas in the gas flow channel from heat transfer and heat radiation to the support structure, greatly reducing the influence of the high-temperature gas on the support structure, greatly improving the stability, reliability and life of the dynamic characteristics of the support structure, and the lubricating oil is not easy to coke, which greatly reduces the risk of bearing lubrication nozzle blockage and lubricating oil failure.

[0016] In addition, the gas turbine engine of the present invention also has the above advantages.

[0017] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0019] Figure 1 It is a schematic diagram of the installation position of the interstage support structure in the gas turbine engine.

[0020] Figure 2 Schematic diagram of a turbine interstage support structure according to a preferred embodiment of the present invention.

[0021] Figure 3 It is a schematic structural diagram of a front baffle ring according to a preferred embodiment of the present invention.

[0022] Figure 4 It is a schematic diagram of the partial cross-sectional structure of the front baffle ring of the preferred embodiment of the present invention.

[0023] Figure 5 It is a partial structural schematic diagram of a turbine interstage support structure according to a preferred embodiment of the present invention.

[0024] Figure 6 It is a schematic structural diagram of an elastic bracket according to a preferred embodiment of the present invention.

[0025] Description of Reference Numerals

[0026] 20. Interstage support structure; 21. Power turbine; 23. Combustion chamber; 24. Gas turbine; 1. Interstage support guide; 2. Heat insulation; 3. Interstage bearing seat; 4. Elastic bracket; 5. First connecting piece; 6. Second connecting piece; 7. Front fulcrum bearing outer ring; 8. Rear fulcrum bearing outer ring; 9. Front baffle ring; 10. Bearing seat front section outer ring; 11. Bearing seat front section inner ring; 12. Front baffle plate; 13. Rear guide plate; 14. Rear baffle plate; 101. Mounting edge; 102 , outer casing of the gas flow channel; 103, guide vanes; 104, inner casing of the gas flow channel; 105, rearward-bending elastic casing; 106, first air flow hole; 107, first mounting hole; 91, first pre-swirl hole; 92, sealing retaining ring; 21, second mounting hole; 41, second air flow hole; 42, W sealing ring; 43, elastic hole; 131, second pre-swirl hole; 31, main lubricating oil flow channel; 32, front lubricating oil flow channel; 33, rear lubricating oil nozzle; 34, third mounting hole. DETAILED DESCRIPTION

[0027] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0028] like Figures 2 to 6 As shown, a preferred embodiment of the present invention provides a turbine interstage support structure, including an interstage support guide 1, a heat insulation member 2, an interstage bearing seat 3, an elastic support 4, a first connecting member 5, a second connecting member 6, a front pivot bearing outer ring 7 and a rear pivot bearing outer ring 8, the upper end of the interstage support guide 1 is fixedly connected to the turbine casing, and the lower end is fixedly connected to the upper end of the elastic support 4 through the first connecting member 5, the lower end of the elastic support 4 is fixedly connected to the rear end of the interstage bearing seat 3 through the second connecting member 6, the front pivot bearing outer ring 7 and the rear pivot bearing outer ring 8 are both installed at the bottom of the interstage bearing seat 3, wherein the front pivot bearing outer ring 7 is the fulcrum of the gas turbine rotor, and the rear pivot bearing outer ring 8 is the fulcrum of the power turbine rotor. The front and rear pivot loads are respectively transmitted to the interstage bearing seat 3 through the front pivot bearing outer ring 7 and the rear pivot bearing outer ring 8, and then transmitted to the elastic bracket 4 through the second connecting member 6, and then transmitted to the interstage support guide 1 through the first connecting member 5, and finally transmitted to the turbine casing. The entire support structure is compact, and the axial and radial dimensions are small. It can not only meet the restriction requirements of the radial dimension between the turbine stages, but also help to reduce the axial size and weight of the engine, thereby reducing the required lubricating oil cooling flow. The interstage support guide 1 is provided with an insulation cavity below the gas flow channel, and the insulation 2 is installed in the insulation cavity and used to isolate the high-temperature gas in the gas flow channel from heat transfer and heat radiation to the support structure. Among them, the material of the insulation 2 is preferably a ceramic fiber blanket or a more efficient insulation material.

[0029] It can be understood that in the turbine interstage support structure of this embodiment, the loads of the gas turbine rotor fulcrum and the power turbine rotor fulcrum are respectively transmitted to the interstage bearing seat 3 through the front fulcrum bearing outer ring 7 and the rear fulcrum bearing outer ring 8, and then transmitted to the elastic bracket 4 through the second connecting member 6, and then transmitted to the interstage support guide 1 through the first connecting member 5, and finally transmitted to the turbine casing. The entire support structure is compact, and the axial and radial dimensions are small, which can not only well meet the restriction requirements of the radial dimension of the turbine interstage, but also help to reduce the axial size and weight of the engine, thereby reducing the required lubricating oil cooling flow. More importantly, a heat insulation cavity is provided below the gas flow channel, and a heat insulation member 2 is installed in the heat insulation cavity, which can effectively isolate the high-temperature gas in the gas flow channel from heat transfer and heat radiation to the support structure, greatly reducing the influence of the high-temperature gas on the support structure, greatly improving the stability, reliability and life of the dynamic characteristics of the support structure, and the lubricating oil is not easy to coke, which greatly reduces the risk of bearing lubrication nozzle blockage and lubricating oil failure.

[0030] It can be understood that the interstage support guide 1 includes an integrally cast mounting edge 101, a gas flow channel outer casing 102, guide vanes 103, a gas flow channel inner casing 104 and a backward bending elastic casing 105, wherein the mounting edge 101 is connected to the gas flow channel outer casing 102 and fixedly mounted on the turbine casing by screws or bolts, a gas flow channel is formed between the gas flow channel outer casing 102 and the gas flow channel inner casing 104, the guide vanes 103 are respectively connected to the gas flow channel outer casing 102 and the gas flow channel inner casing 104, the backward bending elastic casing 105 is connected to the gas flow channel inner casing 104 and forms an annular heat insulation cavity between the two. The heat insulation component 2 is installed in the annular heat insulation cavity.

[0031] Optionally, the interstage support structure also includes a front block ring 9, a front outer ring 10 of the bearing seat, a front inner ring 11 of the bearing seat and a front baffle plate 12, the front outer ring 10 of the bearing seat and the front inner ring 11 of the bearing seat are respectively connected to the front end of the interstage bearing seat 3, and the front outer ring 10 of the bearing seat is respectively connected to the front block ring 9 and the front baffle plate 12, and the front inner ring 11 of the bearing seat is connected to the front baffle plate 12, and a first cooling chamber is formed by the front block ring 9, the front outer ring 10 of the bearing seat, the front inner ring 11 of the bearing seat, the front baffle plate 12, the backward bending elastic casing 105 and the elastic bracket 4, and the upper part of the interstage bearing seat 3 is located in the first cooling chamber. The interstage support guide 1 and the heat insulation 2 are provided with a lubricating oil inlet channel, and the lubricating oil inlet pipe passes through the lubricating oil inlet channel and is installed on the upper part of the interstage bearing seat 3. The first cooling cavity is provided with an axial cooling air flow channel for introducing high-pressure cooling air to efficiently cool the rearward bending elastic casing 105 and the interstage bearing seat 3. Specifically, the interstage support guide 1 is provided with a first mounting hole 107 in the radial direction, the heat insulation 2 is provided with a second mounting hole 21 in the radial direction, and the upper part of the interstage bearing seat 3 is provided with a third mounting hole 34. The first mounting hole 107, the second mounting hole 21 and the third mounting hole 34 are coaxially arranged, and the lubricating oil inlet pipe is installed in the lubricating oil inlet channel formed by the first mounting hole 107, the second mounting hole 21 and the third mounting hole 34. A first cooling cavity is formed by the front baffle ring 9, the front outer ring 10 of the bearing seat, the front inner ring 11 of the bearing seat, the front baffle plate 12, the rearward bent elastic casing 105 and the elastic bracket 4, and an axial cooling air flow channel is opened in the first cooling cavity, so that high-pressure cooling air can be introduced and injected into the first cooling cavity to efficiently cool the rearward bent elastic casing 105 and the interstage bearing seat 3, further isolating the high-temperature combustion gas in the combustion gas flow channel from heat transfer and heat radiation to the supporting structure, further reducing the influence of the high-temperature combustion gas on the supporting structure, further improving the stability, reliability and life of the dynamic characteristics of the supporting structure, and the lubricating oil basically will not coke, and the risk of bearing lubrication nozzle blockage and lubricating oil failure is basically eliminated.

[0032] Specifically, the front baffle ring 9 is provided with a plurality of first pre-swirl holes 91 along the circumferential direction, which are used to introduce high-pressure cooling air from the rear end of the compressor and perform pre-swirl expansion and acceleration on the high-pressure cooling air. The rearward bending elastic casing 105 is provided with a plurality of first air flow holes 106 along the circumferential direction, and the elastic bracket 4 is provided with a second air flow hole 41 at a corresponding position of the first air flow hole 106. The first pre-swirl hole 91 can increase the flow rate of the high-pressure cooling air and reduce its temperature, which is conducive to improving the cooling efficiency and cooling effect, and can reduce the air flow loss. The high-pressure cooling air is introduced into the first cooling cavity through the first pre-swirl hole 91, and flows out of the first cooling cavity through the first air flow hole 106 and the second air flow hole 41, which can realize efficient cooling of the rearward bending elastic casing 105 and the interstage bearing seat 3. Optionally, the angle between the opening direction of the first pre-swirl hole 91 and the cross-sectional plane is 20° to 50°, preferably 30°. Within this range, the pre-swirl effect of the first pre-swirl hole 91 is optimal. In addition, the first air flow holes 106 and the second air flow holes 41 have the same diameter, number and position.

[0033] Optionally, in order to ensure the airtightness of the first sealing cavity and guarantee a high flow rate of the cooling air, a sealing ring 92 is provided between the front retaining ring 9 and the rearward bent elastic casing 105, and a W sealing ring 42 is provided between the elastic bracket 4 and the upper part of the interstage bearing seat 3.

[0034] In addition, the interstage support structure also includes a rear guide plate 13 and a rear baffle plate 14. The rear guide plate 13 is fixedly connected to the elastic bracket 4 and the rearward bent elastic casing 105 through a first connecting member 5. The rear baffle plate 14 is fixedly mounted on the elastic bracket 4. The rear guide plate 13, the rear baffle plate 14 and the elastic bracket 4 together form a second cooling cavity. A gap is left between the rear guide plate 13 and the rear baffle plate 14. A plurality of second pre-swirl holes 131 are opened circumferentially on the rear guide plate 13. The second pre-swirl holes 131 are arranged one-to-one with the second air flow holes 41 and are connected. The high-pressure cooling air in the first cooling cavity flows into the second cooling cavity through the second pre-swirl holes 131. The high-pressure cooling air cools the rear guide plate 13 and then flows out from the gap between the rear guide plate 13 and the rear baffle plate 14. The aperture, number and position of the second pre-swirl holes 131 are the same as those of the second air flow holes 41. Optionally, the angle between the opening direction of the second pre-swirl hole 131 and the cross-sectional plane is 15° to 50°, preferably 30°. Within this range, the pre-swirl effect of the first pre-swirl hole 91 is optimal. The rear guide plate 13, the rear baffle plate 14 and the elastic bracket 4 are combined to form a second cooling cavity, and the high-pressure cooling air in the first cooling cavity is introduced into the second cooling cavity through the second pre-swirl hole 131. Since the rear guide plate 13 is adjacent to the lower part of the interstage support guide 1, its temperature is relatively high. By introducing high-pressure cooling air, the rear guide plate 13 is efficiently cooled, and the airflow finally flows out of the second cooling cavity from the gap between the rear guide plate 13 and the rear baffle plate 14, which can effectively isolate the heat transfer and heat radiation to the elastic bracket 4, further improving the stability and reliability of the support structure.

[0035] It can be understood that the structure of the elastic bracket 4 can adopt a cage bracket design, which is conducive to improving the elastic support effect of the support structure and has a simple structure. Among them, the rigidity and load-bearing requirements of the fulcrum can be controlled by adjusting the number and size of the elastic holes 43 on the elastic bracket 4. In addition, the backward bending elastic casing 105 can also adopt a similar design.

[0036] It can be understood that the interstage bearing seat 3 is provided with a main lubricating oil flow channel 31, a front lubricating oil flow channel 32 and a rear lubricating oil nozzle 33. The front lubricating oil flow channel 32 and the rear lubricating oil nozzle 33 are both connected to the main lubricating oil flow channel 31. The front lubricating oil flow channel 32 is used to lubricate the gas turbine rotor fulcrum, and the rear lubricating oil nozzle 33 is used to lubricate the power turbine rotor fulcrum. The lubricating oil flows through the main lubricating oil flow channel 31 in the interstage bearing seat 3 to the front lubricating oil flow channel 32 and the rear lubricating oil nozzle 33 at the same time, thereby lubricating the gas turbine rotor fulcrum and the power turbine rotor fulcrum. Optionally, the outlet of the rear lubricating oil nozzle 33 is aligned with the power turbine rotor fulcrum, that is, lubrication is performed by direct injection, and a gap is left between the front fulcrum bearing outer ring 7 and the interstage bearing seat 3, and the outlet of the front lubricating oil flow channel 32 is aligned with the gap between the two to form a squeeze film damper, which can play a vibration reduction role and further improve the anti-vibration performance of the support structure.

[0037] In addition, the present invention also provides a gas turbine engine, which preferably adopts the turbine interstage support structure as described above.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A turbine interstage support structure, characterized in that: The invention comprises an interstage support guide (1), a heat insulating member (2), an interstage bearing seat (3), an elastic support (4), a first connecting member (5), a second connecting member (6), a front pivot bearing outer ring (7) and a rear pivot bearing outer ring (8); the upper end of the interstage support guide (1) is connected to the turbine casing, and the lower end is connected to the upper end of the elastic support (4) through the first connecting member (5); the lower end of the elastic support (4) is connected to the rear end of the interstage bearing seat (3) through the second connecting member (6); the front pivot bearing outer ring (7) and the rear pivot bearing outer ring (8) are both mounted on the bottom of the interstage bearing seat (3); the front pivot bearing outer ring (7) is a gas turbine rotor fulcrum, and the rear pivot bearing outer ring (8) is a power turbine rotor fulcrum; an insulation cavity is arranged below the gas flow channel in the interstage support guide (1); the insulation member (2) is mounted in the insulation cavity and is used to isolate the high-temperature gas in the gas flow channel from heat transfer and heat radiation to the support structure; The interstage support guide (1) comprises an integrally cast mounting edge (101), a gas flow channel outer casing (102), guide vanes (103), a gas flow channel inner casing (104) and a backward-bending elastic casing (105); the mounting edge (101) is connected to the gas flow channel outer casing (102) and mounted on the turbine casing; a gas flow channel is formed between the gas flow channel outer casing (102) and the gas flow channel inner casing (104); the guide vanes (103) are respectively connected to the gas flow channel outer casing (102) and the gas flow channel inner casing (104); the backward-bending elastic casing (105) is connected to the gas flow channel inner casing (104) and an annular heat-insulating cavity is formed therebetween; The interstage support structure further comprises a front baffle ring (9), a front outer ring (10) of a bearing seat, a front inner ring (11) of a bearing seat and a front baffle plate (12); the front outer ring (10) of the bearing seat and the front inner ring (11) of the bearing seat are respectively connected to the front end of the interstage bearing seat (3); the front outer ring (10) of the bearing seat is respectively connected to the front baffle ring (9) and the front baffle plate (12); the front inner ring (11) of the bearing seat is connected to the front baffle plate (12); The plate (12), the rearward-bent elastic casing (105) and the elastic bracket (4) together form a first cooling cavity, and the upper part of the interstage bearing seat (3) is located in the first cooling cavity. The interstage support guide (1) and the heat insulation member (2) are provided with a lubricating oil inlet channel, and the lubricating oil inlet pipe passes through the lubricating oil inlet channel and is installed on the upper part of the interstage bearing seat (3). The first cooling cavity is provided with an axial cooling air flow channel for introducing high-pressure cooling air from the compressor to efficiently cool the rearward-bent elastic casing (105) and the interstage bearing seat (3).

2. The turbine interstage support structure according to claim 1, characterized in that: The front baffle ring (9) is provided with a plurality of first pre-swirl holes (91) along the circumferential direction for introducing high-pressure cooling air from the rear end of the compressor and performing pre-swirl expansion and acceleration on the high-pressure cooling air. The rearward-bending elastic casing (105) is provided with a plurality of first air flow holes (106) along the circumferential direction. The elastic bracket (4) is provided with second air flow holes (41) at positions corresponding to the first air flow holes (106). The high-pressure cooling air is introduced into the first cooling cavity through the first pre-swirl holes (91) and flows out of the first cooling cavity through the first air flow holes (106) and the second air flow holes (41).

3. The turbine interstage support structure according to claim 1, characterized in that: A sealing ring (92) is provided between the front retaining ring (9) and the rearward-bending elastic casing (105), and a W sealing ring (42) is provided between the elastic bracket (4) and the upper part of the interstage bearing seat (3).

4. The turbine interstage support structure according to claim 2, characterized in that: The invention also comprises a rear guide plate (13) and a rear baffle plate (14), wherein the rear guide plate (13) is connected to the elastic bracket (4) and the rearward-bending elastic casing (105) through a first connecting member (5), and the rear baffle plate (14) is installed on the elastic bracket (4). The rear guide plate (13), the rear baffle plate (14) and the elastic bracket (4) together form a second cooling cavity, and a gap is left between the rear guide plate (13) and the rear baffle plate (14). A plurality of second pre-swirl holes (131) are opened on the rear guide plate (13) along the circumferential direction, and the second pre-swirl holes (131) are connected with the second air flow holes (41). The high-pressure cooling air in the first cooling cavity flows into the second cooling cavity through the second pre-swirl holes (131), and the high-pressure cooling air cools the rear guide plate (13) and then flows out from the gap between the rear guide plate (13) and the rear baffle plate (14).

5. The turbine interstage support structure according to claim 4, characterized in that: The angle between the opening direction of the first pre-spinning hole (91) and / or the second pre-spinning hole (131) and the section plane is 15° to 50°.

6. The turbine interstage support structure according to claim 1, characterized in that: The interstage bearing seat (3) is provided with a main lubricating oil flow channel (31), a front lubricating oil flow channel (32) and a rear lubricating oil nozzle (33); the front lubricating oil flow channel (32) and the rear lubricating oil nozzle (33) are both connected to the main lubricating oil flow channel (31); the front lubricating oil flow channel (32) is used to form a squeeze film damper structure for the gas turbine rotor fulcrum; the rear lubricating oil nozzle (33) is used to lubricate the power turbine rotor fulcrum.

7. The turbine interstage support structure according to claim 6, characterized in that: The outlet of the rear lubricating oil nozzle (33) is aligned with the power turbine rotor fulcrum, a gap is left between the front fulcrum bearing outer ring (7) and the interstage bearing seat (3), and the outlet of the front lubricating oil flow channel (32) is connected to the gap between the two to form a squeeze film damper.

8. A gas turbine engine, characterized in that: A turbine interstage support structure as claimed in any one of claims 1 to 7 is adopted.

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