Flow path system for coupling bearing cavity axis ventilation and turbine disc cavity ventilation

Abstract

The invention belongs to the field of gas turbine engines, relates to an engine ventilation and cooling flow path design technology, and discloses a bearing cavity axis ventilation and turbine disc cavity ventilation coupled flow path system which comprises a fan shaft, a turbine shaft, a gas compressor shaft, a front bearing cavity, a rear bearing cavity, a bearing cavity axis ventilation flow path and a turbine disc center ventilation flow path. And the air compressor shaft is sleeved on the fan shaft and the turbine shaft. The front bearing cavity and the rear bearing cavity are both communicated with the axis ventilation flow path, and the tail end of the bearing cavity axis ventilation flow path is communicated with the tail end of the turbine disc center ventilation flow path. An oil-gas mixture of the bearing cavity axis ventilation flow path and cooling air of the turbine disc center ventilation flow path are mixed and then discharged into the main flow path. According to the flow path system, the problems of coking and ignition of lubricating oil in the tail cone cavity can be solved through coupling of the bearing cavity axis ventilation flow path and the turbine disc cavity ventilation flow path, the ventilation effect is effectively improved, the pressure of the bearing cavity is reduced, and the problem that the consumption of the lubricating oil is large is solved.

Description

Technical Field

[0001] The present invention belongs to the field of gas turbine engines, and relates to engine ventilation and cooling flow path design technology, and in particular to a flow path system for coupling bearing cavity axial ventilation with turbine disc cavity ventilation. Background Art

[0002] Gas turbine engines usually draw air from the appropriate position of the compressor to establish a lubricating oil sealing environment with pressure and temperature that meet the requirements in the peripheral chamber of the bearing sealing device to prevent the lubricating oil from leaking from the bearing cavity sealing assembly to the engine disc cavity and protect the bearings and lubricating oil from damage by the high-temperature gas environment.

[0003] While effectively sealing the lubricating oil in the bearing cavity, it is inevitable that a certain amount of air will enter the bearing cavity from the gap between the sealing structures and mix with the lubricating oil to form an oil-air mixture. The presence of bubbles in the oil-air mixture in the bearing cavity will lead to a decrease in the bearing lubrication effect, an increase in the lubricating oil pressure in the bearing cavity, and a decrease in the sealing margin. Excessive air in the bearing cavity will lead to increased bearing wear and lubricating oil leakage, which seriously threatens the safe and reliable operation of the engine. Therefore, a ventilation system needs to be designed to ensure that the pressure in the bearing cavity meets the requirements.

[0004] Existing gas turbine engine oil system ventilation design Figure 1 As shown, the hollow engine shaft 101 is usually used to realize axial ventilation. Compared with the throttling ventilation and free ventilation systems, the axial ventilation can save external ventilation pipes, centrifugal ventilators and other accessories, which has a positive effect on reducing the weight and cost of the engine. However, the axial ventilation flow path A is usually designed as an independent flow path, and its exhaust outlet is set at the engine tail cone 105. When the oil-gas mixture in the bearing cavity flows through the tail cone cavity 28 surrounded by the baffle 102, the center cone 103 and the engine tail cone 105, it is easy to cause the lubricating oil to coke and catch fire in the tail cone cavity 28 due to the radiation of the high-temperature combustion gas heat B between the center cone 103 and the inner nozzle 104 and the heat conduction of the center cone 103; at the same time, the outlet of the independent axial ventilation flow path is located at the engine tail cone outlet, and the pressure fluctuation is large due to the influence of the unsteady mainstream of the nozzle outlet, resulting in a large error in the flow path design result, so that the actual ventilation flow path does not meet the design requirements and there is a problem of poor ventilation effect. Summary of the invention

[0005] In order to solve the technical problems of the existing axial ventilation system that lubricating oil is easily coked and ignited in the tail cavity and the ventilation effect is poor, the present invention discloses a flow path system for coupling the axial ventilation of the bearing cavity with the ventilation of the turbine disc cavity, and the flow path system comprises: A compressor shaft, one end of which is sleeved on the fan shaft, and the other end of which is sleeved on the turbine shaft; A front bearing cavity and a rear bearing cavity, wherein the front bearing cavity is surrounded by an intermediate casing, a fan shaft and the front end of the compressor shaft, and the rear bearing cavity is surrounded by a combustion chamber casing, a turbine shaft and the rear end of the compressor shaft, the front bearing cavity is communicated with the axial flow path of the fan shaft, and the rear bearing cavity is communicated with the axial flow path of the turbine shaft, an oil ventilation pipe is provided at the end of the axial flow path of the turbine shaft along the airflow direction, and the hollow axial inner wall of the compressor shaft, the hollow axial inner wall of the fan shaft, the hollow axial inner wall of the turbine shaft and the inner wall of the oil ventilation pipe form the axial ventilation flow path of the bearing cavity; The turbine shaft end journal, the outer wall of the lubricating oil ventilation pipe and the turbine wheel disk form a turbine disk center ventilation flow path. The oil-gas mixture in the bearing cavity shaft center ventilation flow path is mixed with the cooling air in the turbine disk center ventilation flow path and then discharged into the main flow channel.

[0006] Furthermore, a first through hole is provided on the fan shaft, and the first through hole radially penetrates the fan shaft to connect the front bearing cavity with the axial flow path of the fan shaft; a second through hole is provided on the turbine shaft, and the second through hole radially penetrates the turbine shaft to connect the rear bearing cavity with the axial flow path of the turbine shaft, and the fan shaft, the turbine shaft and the compressor shaft are all hollow structures and their axes coincide.

[0007] Furthermore, a fulcrum bearing seat, a fulcrum bearing and a fulcrum sealing assembly are provided between the compressor shaft and the intermediate casing and the combustion chamber casing.

[0008] Furthermore, a vent hole is provided on the shaft neck at the end of the turbine shaft, and cooling air flows into the turbine disk center ventilation flow path through the vent hole.

[0009] Furthermore, the turbine wheel disc includes a first-stage turbine disc and a second-stage turbine disc, a spacer ring is provided between the first-stage turbine disc and the second-stage turbine disc, a rotating cavity is formed between the first-stage turbine disc, the second-stage turbine disc and the spacer ring, and the rotating cavity is connected to the ventilation flow path in the center of the turbine disc.

[0010] Furthermore, a concave cavity is provided at a low radius on the front side of the second-stage turbine disc.

[0011] Furthermore, the lubricating oil ventilation pipe includes a front straight pipe, a middle tapered pipe and a rear straight pipe, the diameter of the front straight pipe is larger than the diameter of the rear straight pipe, thereby forming a tapered circular pipe structure along the airflow direction.

[0012] Furthermore, the front section straight pipe is located near the axis center of the front end of the turbine shaft end journal, and the rear section straight pipe is located at the axis center position below the center of the turbine wheel.

[0013] Furthermore, a disc-shaped air guide wheel is provided between the second-stage turbine disk and the tail cone cavity of the turbine disk. The oil-gas mixture of the axial ventilation flow path of the bearing cavity and the cooling air of the central ventilation flow path of the turbine disk are mixed at the root of the front side of the air guide wheel and then radially discharged into the main channel through the cavity between the air guide wheel and the rear side of the second-stage turbine disk.

[0014] Furthermore, an axial gap is provided between the end of the lubricating oil ventilation pipe and the guide wheel, and the cooling air entering the turbine disc center ventilation flow path guides the oil-gas mixture in the bearing cavity axial ventilation flow path out through the axial gap and mixes it.

[0015] Compared with the prior art, at least one of the above-mentioned technical solutions adopted in the embodiments of this specification can achieve the following beneficial effects at least: the flow path system of the present invention can effectively improve the ventilation effect of the axis of the bearing cavity, and the air in the ventilation path of the turbine disc cavity is used to induce the oil-gas mixture in the axial ventilation path. After the cooling air is mixed with the oil-gas mixture for cooling, it is discharged into the main flow channel through the low-temperature zone under the pressure difference and the centrifugal action of the turbine disc and the guide wheel, thereby avoiding the medium containing the oil-gas mixture from flowing through the high-temperature zone of the tail cavity, and solving the problems of lubricating oil coking and ignition.

[0016] Compared with the existing ventilation structure, the structure of the present invention is simple and the coupling design of the flow path system can realize different functions and has flexible adjustment methods. Through the flow path system that couples the bearing cavity axial ventilation and the turbine disk center ventilation, the high-speed turbine disk center flow draws the low-speed oil-gas mixture out from the axis through the induced suction effect, and then fully mixes with the cooling air, and after cooling, it flows into the main channel through the low-temperature zone under the pressure difference and the centrifugal action of the turbine disk, which not only effectively solves the problems of lubricating oil coking and ignition, but also improves the bearing cavity ventilation effect and solves the problem of large lubricating oil consumption. At the same time, after the two flow paths of different systems are coupled, the excellent ventilation effect can save components such as oil-gas separators and external ventilation pipes, and contribute to engine weight reduction and cost reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a schematic diagram of the ventilation flow diagram of an existing gas turbine engine; Figure 2 It is a schematic diagram of a flow path system for coupling the bearing cavity axial ventilation and the turbine disc cavity ventilation disclosed in an embodiment of the present invention; Among them, 101, engine shaft; 102, baffle; 103, center cone; 104, internal nozzle; 105, engine tail cone; 1, front bearing cavity; 2, rear bearing cavity; 3, fan shaft; 31, first through hole; 4, turbine shaft; 41, second through hole; 42, vent hole; 43, turbine shaft end journal; 5, tension bolt; 6, fan disk; 7, first fulcrum sealing assembly; 8, first fulcrum bearing; 9, first fulcrum bearing seat; 10, intermediate casing; 11, second fulcrum bearing seat; 12, second fulcrum bearing; 13, first Second fulcrum sealing assembly; 14, compressor shaft; 15, third fulcrum sealing assembly; 16, third fulcrum bearing seat; 17, third fulcrum bearing; 18, combustion chamber casing; 19, fourth fulcrum bearing seat; 20, fourth fulcrum bearing; 21, fourth fulcrum sealing assembly; 22, first-stage turbine disk; 23, spacer ring; 24, second-stage turbine disk; 25, guide wheel; 26, lubricating oil ventilation pipe; 27, rotating cavity; 28, tail cavity; 29, concave cavity; 100, bearing cavity axial ventilation flow path; 200, turbine disk center ventilation flow path. DETAILED DESCRIPTION

[0019] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0020] The following describes the implementation methods of the present application through specific specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and the features of the embodiments can be combined with each other in the absence of conflict. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0021] In the description of this embodiment, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the invention.

[0022] In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more features. In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0023] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present disclosure. The illustrations only show components related to the present disclosure rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0024] An embodiment of the present invention discloses a flow path system that couples the axial ventilation of a bearing cavity with the ventilation of a turbine disk cavity. The flow path system can solve the technical problems that the axial ventilation of the bearing cavity is easily exhausted from the tail cavity 28 of the tail cone and lubricating oil is easily coked and ignited, and the poor ventilation effect leads to a large consumption of lubricating oil. The flow path system mainly includes a front bearing cavity 1, a rear bearing cavity 2, a bearing cavity axial ventilation flow path 100 connecting the front bearing cavity 1 and the rear bearing cavity 2, and a turbine disk center ventilation flow path 200.

[0025] Specifically, see Figure 2 As shown, the flow path system includes a compressor shaft 14, a front bearing cavity 1 and a rear bearing cavity 2. The fan shaft 3, the turbine shaft 4 and the compressor shaft 14 are all hollow structures (i.e., the shaft center is hollow and has a flow path), and the outer diameter of the end of the fan shaft 3 and the outer diameter of the front end of the turbine shaft 4 are both smaller than the inner diameter of the front end of the compressor shaft 14, so that the rear end of the fan shaft 3 is sleeved on the front end of the compressor shaft 14, and the front end of the turbine shaft 4 is sleeved on the end of the compressor shaft 14.

[0026] The front bearing cavity 1 is surrounded by the intermediate casing 10, the fan shaft 3 and the front end of the compressor shaft 14, and the rear bearing cavity 2 is surrounded by the combustion chamber casing 18, the turbine shaft 4 and the rear end of the compressor shaft 14. The front bearing cavity 1 is connected to the fan shaft axial flow path, and the rear bearing cavity 2 is connected to the turbine shaft axial flow path. The end of the turbine shaft axial flow path along the airflow direction is provided with a lubricating oil ventilation pipe 26, and the inner wall of the compressor shaft axial inner wall, the fan shaft axial inner wall, the turbine shaft axial inner wall and the inner wall of the lubricating oil ventilation pipe 26 form a bearing cavity axial ventilation flow path 100.

[0027] Among them, see Figure 2 As shown, the turbine shaft end journal 43, the outer wall of the lubricating oil ventilation pipe 26, and the turbine wheel form a turbine wheel center ventilation flow path 200, and the oil-gas mixture of the bearing cavity axis ventilation flow path 100 is mixed with the cooling air of the turbine wheel center ventilation flow path 200 and discharged into the main flow channel.

[0028] Further, see Figure 2 As shown, the fan shaft 3 is provided with a first through hole 31, which penetrates the fan shaft 3 in a radial direction to connect the front bearing cavity 1 with the fan shaft axial flow path; the turbine shaft 4 is provided with a second through hole 41, which penetrates the turbine shaft 4 in a radial direction to connect the rear bearing cavity 2 with the turbine shaft axial flow path, and the axis of the fan shaft 3, the turbine shaft 4 and the compressor shaft 14 coincide. In specific implementation, the number, diameter and position of the first through hole 31 and the second through hole 41 can be designed according to requirements, for example, the diameter of the first through hole 31 can be set to 8mm, the diameter of the second through hole 41 can be set to 5mm, and the number thereof can be set to one or more in the circumferential direction, the position of the first through hole 31 can be set at the front end position, and the second through hole 41 can be set to the middle section.

[0029] Furthermore, a pivot bearing seat, a pivot bearing and a pivot sealing assembly are provided between the compressor shaft 14 and the intermediate casing 10 and the combustion chamber casing 18. Figure 2 As shown, a second fulcrum bearing seat 11, a second fulcrum bearing 12 and a second fulcrum sealing assembly 13 are provided between the front end of the compressor shaft 14 and the intermediate casing 10, and a third fulcrum bearing seat 16, a third fulcrum bearing 17 and a third fulcrum sealing assembly 15 are provided between the rear end of the compressor shaft 14 and the front end of the combustion chamber casing 18. At the same time, a first fulcrum sealing assembly 7, a first fulcrum bearing 8 and a first fulcrum bearing seat 9 are provided between the front end of the intermediate casing 10 and the front end of the fan shaft 3, and the front end of the fan shaft 3 is connected to the fan disk 6 via a tension bolt 5. At the same time, a fourth fulcrum bearing seat 19, a fourth fulcrum bearing 20 and a fourth fulcrum sealing assembly 21 are provided between the rear end of the combustion chamber casing 18 and the rear end of the turbine shaft 4.

[0030] Further, see Figure 2 As shown, a vent hole 42 is provided on the end journal 43 of the turbine shaft, and cooling air flows into the turbine disk center ventilation flow path through the vent hole 42. The turbine wheel comprises a first-stage turbine disk 22 and a second-stage turbine disk 24, a spacer ring 23 is provided between the first-stage turbine disk 22 and the second-stage turbine disk 24, and a rotating cavity 27 is formed between the first-stage turbine disk 22, the second-stage turbine disk 24 and the spacer ring 23, and the rotating cavity 27 is communicated with the turbine disk center ventilation flow path.

[0031] During specific implementation, the cooling air in the turbine disk center ventilation flow path 200 flows into the turbine disk cavity through the vent hole 42 on the journal 43 at the end of the turbine shaft, and then a part of the cooling air enters the rotating cavity 27 formed by the first-stage turbine disk 22, the spacer ring 23, and the second-stage turbine disk 24 under the centrifugal action caused by the rotation of the turbine disk. Under the action of the second-stage turbine disk 24, the cooling air in the rotating cavity 27 forms a larger vortex at the low radius of the rotating cavity; the other part of the cooling air is affected by the vortex at the low radius of the cavity, the actual flow area is reduced, the flow rate is accelerated, and it continues to flow backward along the center of the second-stage turbine disk 24. The oil-gas mixture in the lubricating oil ventilation pipe 26 is sucked out by the ejection effect at the outlet of the center of the second-stage turbine disk 24. After the cooling air is mixed with the oil-gas mixture and cooled, it flows to a high radius under the pressure difference and centrifugal action, and is finally discharged into the main channel through the low-temperature cavity area between the second-stage turbine disk 24 and the guide wheel 25.

[0032] In an improved embodiment, see Figure 2 As shown, a concave cavity 29 is provided at a low radius on the front side of the second-stage turbine disk 24. The airflow in the rotating cavity 27 forms a relatively large vortex under the disturbance of the concave cavity 29, squeezing the actual flow area of ​​the center of the second-stage turbine disk 24. The flow area of ​​the center of the turbine disk decreases along the flow direction of the airflow, and the actual flow channel is a contraction type, which accelerates the flow of the airflow at the center of the disk.

[0033] Further, see Figure 2 As shown, the lubricating oil ventilation pipe 26 includes a front straight pipe, a middle tapered pipe and a rear straight pipe, the diameter of the front straight pipe is larger than the diameter of the rear straight pipe, thereby forming a tapered circular pipe structure along the airflow direction. Specifically, the front straight pipe is located near the axis of the front end of the turbine shaft end journal 43, and the rear straight pipe is located at the axis position below the center of the turbine wheel.

[0034] Further, see Figure 2 As shown, a disc-shaped air guide wheel 25 is provided between the second-stage turbine disk 24 and the tail cone cavity 28 of the turbine disk. The radial middle section of the air guide wheel 25 is connected to the second-stage turbine disk 24 by circumferentially distributed bolts. The air guide wheel 25 can separate the tail cone cavity 28 from the bearing cavity axial ventilation flow path 100 and the turbine disk center ventilation flow path 200 at its front end to prevent the gas of the two flow paths from flowing into the tail cone cavity 28, so that the oil-gas mixture of the bearing cavity axial ventilation flow path 100 and the cooling air of the turbine disk center ventilation flow path 200 are mixed at the root of the front side of the air guide wheel 25 and then radially discharged into the main flow channel through the cavity between the air guide wheel 25 and the rear side of the second-stage turbine disk 24.

[0035] Furthermore, an axial gap is provided between the end of the lubricating oil ventilation pipe 26 and the guide wheel 25, and the cooling air entering the turbine disc center ventilation flow path guides the oil-gas mixture in the bearing cavity axial ventilation flow path out through the axial gap and mixes it.

[0036] When the above-mentioned flow path system is used, the fan shaft 3 and the turbine shaft 4 rotating at the same speed and high speed separate the air containing a small amount of lubricating oil in the front bearing cavity 1 and the rear bearing cavity 2 into the bearing cavity axial ventilation flow path 100 of the fan shaft 3, the compressor shaft 14 and the turbine shaft 4 through the first through hole 31 and the second through hole 41 respectively during operation; under the vortex extrusion at the low radius of the rotating cavity 27, the actual flow channel of the turbine disc center shrinks along the flow direction of the airflow, and the high-speed cooling air flowing in the turbine disc center ventilation flow path 200 guides and sucks the low-speed oil-gas mixture flowing in the bearing cavity axial ventilation flow path 100 to the outlet of the lubricating oil ventilation pipe 26 through momentum exchange at the end of the flow path. At this time, the two flow paths with different speeds, media and functions are coupled together, mixed and cooled, and then flow to the high radius under the pressure difference and centrifugal action, and finally discharged into the main flow channel through the low-temperature cavity area between the second-stage turbine disc 24 and the guide wheel 25, so as to achieve the purge cooling of the turbine disc cavity and the lubricating oil ventilation of the bearing cavity at the same time.

[0037] The flow path system of the present invention can effectively improve the ventilation effect of the axis of the bearing cavity. The air in the ventilation flow path of the turbine disk center is used to induce the oil-gas mixture in the ventilation flow path of the bearing cavity axis. After the cooling air is mixed with the oil-gas mixture for cooling, it is discharged into the main flow channel through the low-temperature zone under the pressure difference and the centrifugal action of the turbine disk and the guide wheel, thereby preventing the medium containing the oil-gas mixture from flowing through the high-temperature zone of the tail cavity, thereby solving the problems of lubricating oil coking and ignition.

[0038] Compared with the existing ventilation structure, the structure of the present invention is simple and the coupling design of the flow path system can realize different functions and has flexible adjustment methods. Through the flow path system that couples the bearing cavity axial ventilation and the turbine disk center ventilation, the high-speed turbine disk center flow draws the low-speed oil-gas mixture out from the axis through the induced suction effect, and after being fully mixed with the cooling air and cooled, it flows into the main channel through the low-temperature zone under the pressure difference and the centrifugal action of the turbine disk and the guide wheel, which not only effectively solves the problems of lubricating oil coking and ignition, but also improves the bearing cavity ventilation effect and solves the problem of large lubricating oil consumption. At the same time, after the two flow paths of different systems are coupled, the excellent ventilation effect can save components such as oil-gas separators and external ventilation pipes, and contribute to engine weight reduction and cost reduction.

[0039] Obviously, those skilled in the art should understand that 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 embodiments of the present invention may have various modifications and changes. 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.

[0040] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A flow path system for coupling the bearing cavity axial ventilation with the turbine disc cavity ventilation, characterized in that: The flow path system comprises: A compressor shaft (14), one end of the compressor shaft (14) being sleeved on the fan shaft (3) and the other end of the compressor shaft (14) being sleeved on the turbine shaft (4); A front bearing chamber (1) and a rear bearing chamber (2), wherein the front bearing chamber (1) is surrounded by an intermediate casing (10), a fan shaft (3) and a front end of the compressor shaft (14), and the rear bearing chamber (2) is surrounded by a combustion chamber casing (18), a turbine shaft (4) and a rear end of the compressor shaft (14), the front bearing chamber (1) is connected to an axial flow path of the fan shaft, and the rear bearing chamber (2) is connected to an axial flow path of the turbine shaft, an oil ventilation pipe (26) is provided at the end of the axial flow path of the turbine shaft along the airflow direction, and the hollow axial inner wall of the compressor shaft, the hollow axial inner wall of the fan shaft, the hollow axial inner wall of the turbine shaft and the inner wall of the oil ventilation pipe (26) form a bearing chamber axial ventilation flow path (100); The turbine shaft end journal (43), the outer wall of the lubricating oil ventilation pipe (26), and the turbine wheel disk form a turbine wheel disk central ventilation flow path (200), and the oil-gas mixture in the bearing cavity shaft central ventilation flow path (100) is mixed with the cooling air in the turbine wheel disk central ventilation flow path (200) and then discharged into the main flow channel.

2. The flow path system for coupling the bearing cavity axial ventilation and the turbine disc cavity ventilation according to claim 1 is characterized in that: The fan shaft (3) is provided with a first through hole (31), the first through hole (31) radially penetrating the fan shaft (3) to connect the front bearing cavity (1) with the axial flow path of the fan shaft; the turbine shaft (4) is provided with a second through hole (41), the second through hole (41) radially penetrating the turbine shaft (4) to connect the rear bearing cavity (2) with the axial flow path of the turbine shaft, the fan shaft (3), the turbine shaft (4) and the compressor shaft (14) are all hollow structures and their axes coincide.

3. The flow path system for coupling the bearing cavity axial ventilation and the turbine disc cavity ventilation according to claim 1 is characterized in that: A pivot bearing seat, a pivot bearing and a pivot sealing assembly are provided between the compressor shaft (14), the intermediate casing (10) and the combustion chamber casing (18).

4. The flow path system for coupling the bearing cavity axial ventilation and the turbine disc cavity ventilation according to claim 1 is characterized in that: A vent hole (42) is provided on the turbine shaft terminal journal (43), and cooling air flows into the turbine disk core ventilation flow path (200) through the vent hole (42).

5. The flow path system for coupling the bearing cavity axial ventilation and the turbine disc cavity ventilation according to claim 1 is characterized in that: The turbine wheel disc comprises a first-stage turbine disc (22) and a second-stage turbine disc (24); a spacer ring (23) is provided between the first-stage turbine disc (22) and the second-stage turbine disc (24); a rotating cavity (27) is enclosed between the first-stage turbine disc (22), the second-stage turbine disc (24) and the spacer ring (23); and the rotating cavity (27) is communicated with a ventilation flow path (200) at the center of the turbine disc.

6. The flow path system for coupling the bearing cavity axial ventilation and the turbine disc cavity ventilation according to claim 5 is characterized in that: A concave cavity (29) is provided at a low radius on the front side of the second-stage turbine disk (24).

7. The flow path system for coupling the bearing cavity axial ventilation and the turbine disc cavity ventilation according to claim 1 is characterized in that: The lubricating oil ventilation pipe (26) comprises a front straight pipe, a middle tapered pipe and a rear straight pipe, wherein the diameter of the front straight pipe is greater than the diameter of the rear straight pipe.

8. The flow path system for coupling the bearing cavity axial ventilation and the turbine disc cavity ventilation according to claim 7 is characterized in that: The front straight pipe is located near the axis center of the front end of the turbine shaft end journal (43), and the rear straight pipe is located at the axis center position below the turbine wheel disc center.

9. The flow path system for coupling the bearing cavity axial ventilation and the turbine disc cavity ventilation according to claim 1 is characterized in that: An air guide wheel (25) of a disc-shaped structure is provided between the second-stage turbine disk (24) of the turbine wheel disk and the tail cone cavity (28); the oil-gas mixture of the bearing cavity axial ventilation flow path (100) and the cooling air of the turbine disk center ventilation flow path (200) are mixed at the root of the front side of the air guide wheel (25) and then discharged radially into the main flow channel through the cavity between the air guide wheel (25) and the rear side of the second-stage turbine disk (24).

10. The flow path system for coupling the bearing cavity axial ventilation and the turbine disc cavity ventilation according to claim 9, characterized in that: An axial gap is provided between the end of the lubricating oil ventilation pipe (26) and the guide wheel (25), and the cooling air entering the turbine disc center ventilation flow path (200) guides the oil-gas mixture in the bearing cavity axial ventilation flow path (100) out through the axial gap and mixes the mixture.

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