An air supply system for a gas turbine bearing sealing cavity

Abstract

The present invention provides an air supply system for a gas turbine bearing sealing cavity, comprising a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine, a low-pressure turbine, a power turbine, a low-pressure compressor front bearing cavity, a transition section bearing cavity, a high-pressure compressor rear bearing cavity, a low-pressure turbine support ring bearing cavity and a power turbine support ring bearing cavity. By adopting a cooling technology, the sealing air cooled by three gas-liquid air coolers flows through four bearing cavity flow channels, two cold air surround cavities, and an inner hole of the output shaft before flowing into the bearing sealing cavity, thereby reducing heat generation in the gas turbine bearing cavity. Due to the adoption of a reasonable air supply system, it is possible not only to effectively isolate the convective heat exchange between the high-temperature air outside the bearing cavity and the cavity wall, but also to effectively cool the bearing cavity wall temperature, thereby reducing the convective heat exchange between the bearing cavity wall and the lubricating oil and oil and gas in the cavity.

Description

Technical Field

[0001] The invention belongs to the technical field of gas turbines, and in particular relates to an air supply system for a bearing sealing cavity of a gas turbine. Background Art

[0002] A gas turbine is a high-speed rotating power machine that uses a continuously flowing gas as a working fluid to drive the impeller to rotate at high speed, converting the energy of the fuel into useful work. The gas turbine rotor is mostly supported by rolling bearings. As the temperature, speed and thermal load before the gas turbine turbine continue to increase, in order to ensure the normal operation of the rolling bearings, the lubricating oil system and main bearing cavity sealing technology are particularly important.

[0003] The existing three-shaft gas turbine device has a total of five bearing cavities, namely the low-pressure compressor front bearing cavity, the transition section bearing cavity, the high-pressure compressor rear bearing cavity, the low-pressure turbine support ring bearing cavity and the power turbine support ring bearing cavity. Since the high-pressure compressor rear bearing cavity, the low-pressure turbine support ring bearing cavity and the power turbine support ring bearing cavity are relatively small in size and are located in the high-temperature area of ​​the gas turbine, the oil inlet, sealing air and ambient temperature are relatively high. In order to prevent the lubricating oil in the bearing cavity from leaking, it is necessary to introduce compressed air from the transition section to the sealing cavity of the bearing cavity. Due to the air pressure The temperature after shrinkage is relatively high, and the high-temperature sealing air enters the bearing cavity through the sealing device to mix with the oil and gas, causing the lubricating oil in the cavity to heat up and evaporate to form an oil-gas mixture with a certain temperature and pressure. Since the sealing air has a relatively high temperature, when the high-temperature air flows through the bearing cavity flow channel, the cavity flow channel is wrapped by the hot air of the high-temperature air, and then this part of the air enters the bearing cavity from the sealing device, thereby bringing a certain amount of heat to the lubricating oil in the bearing cavity, causing the temperature of the lubricating oil and oil and gas in the bearing cavity to rise, and the wind resistance of the bearing rotation to increase, while also increasing the adverse effects of heat generation at the sealing device. Summary of the Invention

[0004] The purpose of the present invention is to provide an air supply system for a gas turbine bearing sealing cavity, aiming to solve the problems that the sealing air system does not have a simple system, good cooling effect, simple cavity structure, low lubricating oil return temperature and extended lubricating oil service life.

[0005] The present invention is achieved in this way: an air supply system for a gas turbine bearing sealing cavity includes a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine, a low-pressure turbine, a power turbine, a low-pressure compressor front bearing cavity, a transition section bearing cavity, a high-pressure compressor rear bearing cavity, a low-pressure turbine support ring bearing cavity and a power turbine support ring bearing cavity. The high-pressure compressor includes a transition section and a bearing casing, the low-pressure turbine includes a low-pressure turbine support ring, and the power turbine includes a power turbine support ring and an output shaft. Sealed air is extracted from the transition section. For the high-pressure compressor rear bearing cavity, the sealed air flows into an air-liquid air cooler through an external air pipe and flows to the bearing casing after cooling. The interface on the casing is introduced into the high-pressure compressor rear casing bearing cavity through the intermediate air supply pipe; for the low-pressure turbine support ring bearing cavity, the sealed air flows into the gas-liquid air cooler 2 through the external air pipe, and after cooling, flows to the interface on the low-pressure turbine support ring, and is introduced into the low-pressure turbine support ring bearing cavity through the intermediate air flow channel; for the power turbine support ring bearing cavity, the sealed air flows into the gas-liquid air cooler 3 through the external air pipe, and after cooling, flows to the pipe mouth on the power turbine support ring, and flows into the power turbine support ring bearing cavity through the intermediate air supply pipe. The cooling medium flows in from the inlet of gas-liquid air cooler 1, gas-liquid air cooler 2 and liquid air cooler 3, and flows out from the outlet.

[0006] Furthermore, the sealed air is drawn from the air pipe ports and supplied to the gas-liquid air cooler 1, the gas-liquid air cooler 2 and the gas-liquid air cooler 3 respectively through the external air pipe 1, the external air pipe 2 and the external air pipe 3.

[0007] Furthermore, after the sealed air is cooled from the gas-liquid air cooler 1, the gas-liquid air cooler 2 and the gas-liquid air cooler 3, it flows to the air pipe openings on the load-bearing casing, the low-pressure turbine support ring and the power turbine support ring through the external air pipe 1, the external air pipe 2 and the external air pipe 3 respectively to supply air.

[0008] Furthermore, the air pipe opening on the load-bearing casing flows into the high-pressure compressor rear bearing cavity through the intermediate air supply pipe, and the flow channel two flowing into the bearing cavity is divided into two paths, respectively entering the sealing cavity one and the sealing cavity two through the cold air surround cavity one and the cold air surround cavity two. Under the action of the pressure difference between the sealing cavity one and the sealing cavity two and the bearing cavity one, the lubricating oil is prevented from leaking outward from the sealing device one and the sealing device two. The grate sealing device one and the grate sealing device two play a role in preventing external high-temperature air from entering the sealing cavity one and the sealing cavity two. Since the temperature of the cooled sealing air is relatively low, it can play a role in cooling the high-pressure compressor rear bearing cavity one. Therefore, the thermal insulation coating layer one, the thermal insulation coating layer two and the thermal insulation coating layer three may not be provided.

[0009] Furthermore, the air pipe opening on the low-pressure turbine support ring flows into the low-pressure turbine support ring bearing cavity through the intermediate air supply pipe three, and flows into the sealing cavity three through the bearing cavity flow channel three. Under the action of the pressure difference between the sealing cavity three and the bearing cavity two, the lubricating oil is prevented from leaking outward from the sealing device three. The comb seal device three prevents external high-temperature air from entering the sealing cavity three. Since the temperature of the cooled sealing air is relatively low, it can cool the low-pressure turbine support ring bearing cavity. Therefore, the thermal insulation coating layer three may not be provided.

[0010] Furthermore, the air pipe opening on the power turbine support ring flows into the power turbine support ring bearing cavity through the intermediate air supply pipe 1, and flows into the sealing cavity 4 through the bearing cavity flow channel 1. The sealed air flows along the output shaft inner hole flow channel into the sealing cavity 5. Under the action of the pressure difference between the sealing cavity 4, the sealing cavity 5 and the bearing cavity 3, the lubricating oil is prevented from leaking outward from the sealing device 4 and the sealing device 5. The comb seal device 4 plays a role in preventing the sealing air from leaking outward. A part of the sealing air flows into the power turbine flow along the bearing cavity flow channel 4. Since the temperature of the sealing air after cooling is relatively low, the thermal insulation coating layer 5 and the thermal insulation coating layer 4 in the bearing cavity flow channel 4 may not be set.

[0011] Furthermore, the transition section bearing cavity contains a low-pressure compressor rear bearing and a high-pressure compressor front bearing.

[0012] The beneficial effects of the present invention are:

[0013] By adopting cooling technology, the sealed air cooled by the three gas-liquid air coolers flows through the four bearing cavity flow channels, two cold air surround cavities, and the inner hole of the output shaft and then flows into the bearing sealing cavity, which can reduce the heat generation in the gas turbine bearing cavity. Due to the adoption of a reasonable air supply system, it can not only effectively isolate the convective heat exchange between the high-temperature air outside the bearing cavity and the cavity wall, but also effectively cool the bearing cavity wall temperature, thereby reducing the convective heat exchange between the bearing cavity wall and the lubricating oil and oil and gas in the cavity. At the same time, the cooled sealed air enters the bearing cavity and exchanges heat with the high-temperature lubricating oil and oil and gas in the cavity, which can reduce the lubricating oil temperature and oil and gas temperature in the bearing cavity, and can also reduce the wind resistance of the main bearing rolling element, which can meet the requirements of the gas turbine air supply system for low lubricating oil leakage, good cooling effect, low lubricating oil return temperature, extended lubricating oil service life, and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic structural diagram of a three-shaft gas turbine according to the present invention;

[0015] Figure 2 Schematic diagram of the air bleed pipe distribution structure of the AA section of the transition section behind the low-pressure compressor of the present invention;

[0016] Figure 3 It is a schematic diagram of the air intake pipe distribution structure of the load-bearing casing BB section, the low-pressure turbine support ring CC section, and the power turbine support ring DD section of the present invention;

[0017] Figure 4 is an enlarged view of the rear bearing cavity of the high-pressure compressor of the present invention;

[0018] Figure 5 It is an enlarged view II of the bearing cavity of the low-pressure turbine support ring of the present invention;

[0019] Figure 6 It is an enlarged view of the bearing cavity of the power turbine support ring of the present invention.

[0020] In the figure: 1. low-pressure compressor; 2. high-pressure compressor; 3. combustion chamber; 4. high-pressure turbine; 5. low-pressure turbine; 6. power turbine; 7. low-pressure compressor front bearing cavity; 8. transition section bearing cavity; 9. high-pressure compressor rear bearing cavity 1; 10. high-pressure compressor rear bearing cavity 2; 11. power turbine support ring bearing cavity; 12. transition section; 13. load-bearing casing; 14. low-pressure turbine support ring; 15. low-pressure turbine support ring; 16. external air pipe 1; 17. external air pipe 2; 18. external air pipe 3; 19. output shaft; 20. gas-liquid air cooler 1; 21. gas-liquid air cooler 2; 22. gas-liquid air cooler 3; 23. intermediate air supply pipe 1; 24. intermediate air supply pipe 2; 25. cold air surround cavity 1; 26. cold air surround cavity 2; 27. thermal insulation coating 1; 28 29. Sealing chamber 1; 30. Sealing chamber 2; 31. Sealing device 1; 32. Sealing device 2; 33. Bearing chamber 1; 34. Grate seal device 1; 35. Grate seal device 2; 36. Intermediate air supply pipe 3; 37. Sealing chamber 3; 38. Bearing chamber 2; 39. Sealing device 3; 40. Grate seal device 3; 41. Thermal insulation coating 3; 42. Bearing chamber flow channel 1 ; 43. Sealing chamber four; 44. Sealing chamber five; 45. Sealing device four; 46. Sealing device five; 47. Bearing chamber three; 48. Comb sealing device four; 49. Comb sealing device five; 50. Thermal insulation coating layer four; 51. Thermal insulation coating layer five; 52. Bearing cavity flow channel two; 53. Bearing cavity flow channel three; 54. Bearing cavity flow channel four; 55. Thermal insulation coating layer six; 56. Inlet; 57. Outlet. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to the accompanying drawings.

[0022] The embodiment of the present invention provides a sealed air system, such as Figure 1-6As shown, it includes a low-pressure compressor 1, a high-pressure compressor 2, a combustion chamber 3, a high-pressure turbine 4, a low-pressure turbine 5, a power turbine 6, a low-pressure compressor front bearing cavity 7, a transition section bearing cavity 8, a high-pressure compressor rear bearing cavity 9, a low-pressure turbine support ring bearing cavity 10 and a power turbine support ring bearing cavity 11. The high-pressure compressor 2 includes a transition section 12 and a load-bearing casing 13, the low-pressure turbine 5 includes a low-pressure turbine support ring 14, and the power turbine 6 includes a power turbine support ring 15 and an output shaft 19. Sealed air is extracted from the transition section 12. For the high-pressure compressor rear bearing cavity 9, the sealed air flows into the gas-liquid air cooler 20 through the external air pipe 16, and after cooling, flows to the interface on the load-bearing casing 13 and is supplied through the intermediate air supply pipe. 24 is introduced into the high-pressure compressor rear casing bearing cavity 9; for the low-pressure turbine support ring bearing cavity 10, the sealed air flows into the gas-liquid air cooler 2 21 through the external air pipe 17, flows to the interface on the low-pressure turbine support ring 14 after cooling, and is introduced into the low-pressure turbine support ring bearing cavity 10 through the intermediate air flow channel; for the power turbine support ring bearing cavity 11, the sealed air flows into the gas-liquid air cooler 3 22 through the external air pipe 18, flows to the pipe mouth on the power turbine support ring 15 after cooling, flows to the power turbine support ring bearing cavity 11 through the intermediate air supply pipe, and the cooling medium flows in from the inlet 56 of the gas-liquid air cooler 1 20, the gas-liquid air cooler 21 and the gas-liquid air cooler 3 22, and flows out from the outlet 57.

[0023] It should be noted that, since the existing three-shaft gas turbine device has a total of five bearing cavities, namely the low-pressure compressor front bearing cavity, the transition section bearing cavity, the high-pressure compressor rear bearing cavity, the low-pressure turbine support ring bearing cavity and the power turbine support ring bearing cavity, etc., since the high-pressure compressor rear bearing cavity, the low-pressure turbine support ring bearing cavity and the power turbine support ring bearing cavity are relatively small in size and are located in the high-temperature area of ​​the gas turbine, the oil inlet, sealing air and ambient temperature are relatively high. In order to prevent the lubricating oil in the bearing cavity from leaking, it is necessary to lead compressed air from the transition section to the sealing of the bearing cavity. In the strict cavity, due to the high temperature of the air after compression, the high-temperature sealing air enters the bearing cavity through the sealing device to mix with the oil and gas, causing the lubricating oil in the cavity to heat up and volatilize to form an oil-gas mixture with a certain temperature and pressure. Since the sealing air has a high temperature, when the high-temperature air flows through the bearing cavity flow channel, the cavity flow channel is wrapped by the hot air of the high-temperature air, and then this part of the air enters the bearing cavity from the sealing device, thereby bringing a certain amount of heat to the lubricating oil in the bearing cavity, causing the temperature of the lubricating oil and oil and gas in the bearing cavity to rise, and the wind resistance of the bearing rotation to increase, while also increasing the sealing device. Therefore, in order to solve the problem that the existing sealing air system does not have the advantages of simple system, good cooling effect, simple cavity structure, low oil return temperature and extended oil service life, this solution adopts cooling technology. The sealing air cooled by the three gas-liquid air coolers flows through the four bearing cavity flow channels, two cold air surrounding cavities, and the inner hole of the output shaft 19 before flowing into the bearing sealing cavity, which can reduce the heat generation in the gas turbine bearing cavity. Due to the use of a reasonable air supply system, it can not only effectively isolate the outside of the bearing cavity The convective heat exchange between the high-temperature air and the cavity wall also effectively cools the bearing cavity wall temperature, thereby reducing the convective heat exchange between the bearing cavity wall and the lubricating oil and oil gas in the cavity. At the same time, the cooled sealed air enters the bearing cavity and exchanges heat with the high-temperature lubricating oil and oil gas in the cavity, which can reduce the lubricating oil temperature and oil gas temperature in the bearing cavity, and can also reduce the wind resistance of the main bearing rolling elements, which can meet the requirements of the gas turbine air supply system for low lubricating oil leakage, good cooling effect, low lubricating oil return temperature, extended lubricating oil service life, and high reliability.

[0024] Specifically, in this embodiment, this scheme mainly includes sealing air and drawing air from the air pipe openings, and supplying air to the gas-liquid air cooler 1 20, the gas-liquid air cooler 2 21 and the gas-liquid air cooler 3 22 respectively through the external air pipe 1 16, the external air pipe 2 17 and the external air pipe 3 18.

[0025] In a further preferred embodiment of the present invention, Figure 1-5As shown, after the sealed air is cooled by the gas-liquid air cooler 1 20, the gas-liquid air cooler 2 21 and the gas-liquid air cooler 3 22, it flows to the air pipe openings on the load-bearing casing 13, the low-pressure turbine support ring 14 and the power turbine support ring 15 through the external air pipe 1 16, the external air pipe 2 17 and the external air pipe 3 18 respectively for air supply.

[0026] In this embodiment, when the gas turbine is operating under all operating conditions, the main bearings supporting the high-pressure rotor, low-pressure rotor and power turbine rotor can operate normally at high speed. This is mainly due to the combined action of the oil supply system, oil return system, ventilation system and air supply system to keep the working pressure in the bearing cavity in a certain equilibrium state. The air supply system draws sealing air from the transition section, and then passes it into the bearing sealing cavity after passing through the gas-liquid air cooler 1 20, the gas-liquid air cooler 21 and the gas-liquid air cooler 3 22, ensuring that the positive pressure difference between the sealing cavity and the bearing cavity is within the normal operating range, thereby preventing the lubricating oil in the bearing cavity from leaking out from the sealing device. The cold air surround cavity is a flow channel arranged on the outer wall of the bearing cavity, and its interior is filled with cooled air, forming a cold air package here, which can achieve the effect of cooling the bearing cavity. The output shaft inner hole flow channel is a flow channel, and when the sealing air flows through the bearing cavity flow channel, it can play a certain cooling role.

[0027] In a further preferred embodiment of the present invention, Figure 1-5 As shown, the air pipe port on the load-bearing casing 13 flows into the high-pressure compressor rear bearing cavity 9 through the intermediate air supply pipe 24, and the air flowing into the bearing cavity flow channel 2 52 is divided into two paths, respectively entering the sealing cavity 1 29 and the sealing cavity 2 30 through the cold air surround cavity 1 25 and the cold air surround cavity 2 26. Under the action of the pressure difference between the sealing cavity 1 29 and the sealing cavity 2 30 and the bearing cavity 1 33, the lubricating oil is prevented from leaking outward from the sealing device 1 31 and the sealing device 2 32. The grate seal device 1 34 and the grate seal device 2 35 play a role in preventing external high-temperature air from entering the sealing cavity 1 29 and the sealing cavity 2 30. Since the temperature of the cooled sealing air is relatively low, it can play a role in cooling the high-pressure compressor rear bearing cavity 9. Therefore, the thermal insulation coating layer 1 27, the thermal insulation coating layer 2 28 and the thermal insulation coating layer 3 55 may not be provided.

[0028] In this embodiment, the lubricating oil can be prevented from leaking outward under the action of pressure difference, and the external high-temperature air can be prevented from entering the sealing cavity. Since the temperature of the sealed air after cooling is low, it can cool the bearing cavity 9.

[0029] In a further preferred embodiment of the present invention, Figure 1-5As shown, the air pipe port on the low-pressure turbine support ring 14 flows into the low-pressure turbine support ring bearing cavity 10 through the intermediate air supply pipe three 36, and flows into the sealing cavity three 37 through the bearing cavity flow channel three 53. Under the action of the pressure difference between the sealing cavity three 37 and the bearing cavity two 38, the lubricating oil is prevented from leaking outward from the sealing device three 39. The comb seal device three 40 prevents external high-temperature air from entering the sealing cavity three 37. Since the temperature of the cooled sealing air is relatively low, it can cool the low-pressure turbine support ring bearing cavity 10. Therefore, the thermal insulation coating layer three 41 may not be provided.

[0030] In this embodiment, the lubricating oil can be prevented from leaking outward under the action of the pressure difference, thereby preventing external high-temperature air from entering the sealing cavity 37.

[0031] In a further preferred embodiment of the present invention, Figure 1-5 As shown, the air pipe port on the power turbine support ring 15 flows into the power turbine support ring bearing cavity 11 through the intermediate air supply pipe 23, and flows into the sealing cavity 4 43 through the bearing cavity flow channel 42. The sealed air flows along the inner hole flow channel of the output shaft 19 into the sealing cavity 5 44. Under the action of the pressure difference between the sealing cavity 43, the sealing cavity 5 44 and the bearing cavity 3 47, the lubricating oil is prevented from leaking outward from the sealing device 4 45 and the sealing device 5 46. The comb seal device 4 48 plays a role in preventing the sealing air from leaking outward. A part of the sealing air flows into the power turbine flow along the bearing cavity flow channel 4 54. Since the temperature of the sealed air after cooling is relatively low, the thermal insulation coating layer 5 51 and the thermal insulation coating layer 4 50 in the bearing cavity flow channel 4 54 may not be provided.

[0032] In this embodiment, it plays a role in preventing the sealed air from leaking outward.

[0033] In a further preferred embodiment of the present invention, Figure 1 As shown, the transition section bearing cavity 8 contains the low-pressure compressor rear bearing and the high-pressure compressor front bearing.

[0034] In this embodiment, it can play the role of being able to carry out activities after positioning.

[0035] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An air supply system for a gas turbine bearing sealing cavity, characterized in that: The invention comprises a low-pressure compressor (1), a high-pressure compressor (2), a combustion chamber (3), a high-pressure turbine (4), a low-pressure turbine (5), a power turbine (6), a low-pressure compressor front bearing cavity (7), a transition section bearing cavity (8), a high-pressure compressor rear bearing cavity (9), a low-pressure turbine support ring bearing cavity (10) and a power turbine support ring bearing cavity (11), wherein the high-pressure compressor (2) comprises a transition section (12) and a bearing casing (13), the low-pressure turbine (5) comprises a low-pressure turbine support ring (14), and the power turbine (6) comprises a power turbine support ring (15) and an output shaft (19), and sealed air is extracted from the transition section (12). For the high-pressure compressor rear bearing cavity (9), the sealed air flows into an air-liquid air cooler (20) through an external air pipe (16), and flows to an interface on the bearing casing (13) after being cooled. The air is introduced into the high-pressure compressor rear casing bearing cavity (9) through the intermediate air supply pipe (24); for the low-pressure turbine support ring bearing cavity (10), the sealed air flows into the gas-liquid air cooler 2 (21) through the external air pipe 2 (17), flows to the interface on the low-pressure turbine support ring (14) after cooling, and is introduced into the low-pressure turbine support ring bearing cavity (10) through the intermediate air flow channel; for the power turbine support ring bearing cavity (11), the sealed air flows into the gas-liquid air cooler 3 (22) through the external air pipe 3 (18), flows to the pipe opening on the power turbine support ring (15) after cooling, flows into the power turbine support ring bearing cavity (11) through the intermediate air supply pipe, and the cooling medium flows into the gas-liquid air cooler 1 (20), the gas-liquid air cooler 2 (21) and the gas-liquid air cooler 3 (22) from the inlet (56), and flows out from the outlet (57).

2. The air supply system for the gas turbine bearing seal cavity according to claim 1, characterized in that: The sealed air is drawn from the air pipe ports and supplied to the gas-liquid air cooler 1 (20), the gas-liquid air cooler 2 (21) and the gas-liquid air cooler 3 (22) respectively through the external air pipe 1 (16), the external air pipe 2 (17) and the external air pipe 3 (18).

3. The air supply system for the gas turbine bearing sealing cavity according to claim 1, characterized in that: After being cooled by the gas-liquid air cooler 1 (20), the gas-liquid air cooler 2 (21) and the gas-liquid air cooler 3 (22), the sealed air flows through the external air pipe 1 (16), the external air pipe 2 (17) and the external air pipe 3 (18) to the air pipe openings on the load-bearing casing (13), the low-pressure turbine support ring (14) and the power turbine support ring (15) for air supply.

4. The air supply system for the gas turbine bearing sealing cavity according to claim 1, characterized in that: The air pipe port on the load-bearing casing (13) flows into the high-pressure compressor rear bearing cavity (9) through the intermediate air supply pipe (24), and flows into the bearing cavity flow channel 2 (52) and is divided into two paths, respectively entering the sealing cavity 1 (29) and the sealing cavity 2 (30) through the cold air surrounding cavity 1 (25) and the cold air surrounding cavity 2 (26). Under the action of the pressure difference between the sealing cavity 1 (29) and the sealing cavity 2 (30) and the bearing cavity 1 (33), the lubricating oil is prevented from flowing out of the sealing device. The first (31) and the second (32) sealing devices leak outwards, and the first (34) and the second (35) sealing devices prevent the external high-temperature air from entering the sealing chamber 1 (29) and the second (30) sealing chamber. Since the temperature of the cooled sealing air is relatively low, it can cool the high-pressure compressor rear bearing chamber (9). Therefore, the first (27), the second (28) and the third (55) thermal insulation coating layers are not provided.

5. The air supply system for the gas turbine bearing sealing cavity according to claim 1, characterized in that: The air pipe opening on the low-pressure turbine support ring (14) flows into the low-pressure turbine support ring bearing cavity (10) through the intermediate air supply pipe three (36), and flows into the sealing cavity three (37) through the bearing cavity flow channel three (53). Under the action of the pressure difference between the sealing cavity three (37) and the bearing cavity two (38), the lubricating oil is prevented from leaking outward from the sealing device three (39). The grate seal device three (40) plays a role in preventing external high-temperature air from entering the sealing cavity three (37). Since the temperature of the cooled sealing air is relatively low, it can play a role in cooling the low-pressure turbine support ring bearing cavity (10). Therefore, the heat insulation coating layer six (41) is not provided.

6. The air supply system for the gas turbine bearing seal cavity according to claim 1, characterized in that: The air pipe opening on the power turbine support ring (15) flows into the power turbine support ring bearing cavity (11) through the intermediate air supply pipe 1 (23), and flows into the sealing cavity 4 (43) through the bearing cavity flow channel 1 (42). The sealing air flows along the inner hole flow channel of the output shaft (19) into the sealing cavity 5 (44). Under the action of the pressure difference between the sealing cavity 4 (43), the sealing cavity 5 (44) and the bearing cavity 3 (47), the lubricating oil is prevented from leaking outward from the sealing device 4 (45) and the sealing device 5 (46). The grate seal device 4 (48) plays a role in preventing the sealing air from leaking outward. A part of the sealing air flows into the power turbine flow along the bearing cavity flow channel 4 (54). Since the temperature of the cooled sealing air is relatively low, the thermal insulation coating layer 5 (51) and the thermal insulation coating layer 4 (50) are not provided in the bearing cavity flow channel 4 (54).

7. The air supply system for the gas turbine bearing seal cavity according to claim 1, characterized in that: The transition section bearing cavity (8) contains a low-pressure compressor rear bearing and a high-pressure compressor front bearing.

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