A flow path system coupling the axial ventilation of the bearing cavity and the ventilation of the turbine disk cavity

Abstract

The present invention belongs to the field of gas turbine engines, relates to the technologies of engine ventilation and cooling flow path design, and discloses a flow path system for coupling the axial ventilation of a bearing chamber and the ventilation of a turbine disk chamber. The flow path system includes: a fan shaft, a turbine shaft, a compressor shaft, a front bearing chamber, a rear bearing chamber, an axial ventilation flow path of the bearing chamber, and a ventilation flow path of the turbine disk center. The compressor shaft is sleeved on the fan shaft and the turbine shaft. Both the front bearing chamber and the rear bearing chamber are communicated with the axial ventilation flow path, and the end of the axial ventilation flow path of the bearing chamber is communicated with the end of the ventilation flow path of the turbine disk center; the oil-gas mixture in the axial ventilation flow path of the bearing chamber is mixed with the cooling air in the ventilation flow path of the turbine disk center and then discharged into the main flow path. The flow path system of the present invention can solve the problems of lubricating oil coking and ignition in the tail cone chamber by coupling the axial ventilation of the bearing chamber and the ventilation flow path of the turbine disk chamber, effectively improve the ventilation effect, reduce the pressure in the bearing chamber, and solve the problem of large lubricating oil consumption.

Description

Technical Field

[0001] The present invention belongs to the field of gas turbine engines, and relates to the technologies of engine ventilation and cooling flow path design. Specifically, it relates to a flow path system that couples the axial ventilation of the bearing cavity and the ventilation of the turbine disk cavity. Background Art

[0002] Gas turbine engines usually bleed air from a suitable position of the compressor to establish a hermetic environment with appropriate pressure and temperature around the bearing seal device, so as to prevent the lubricating oil from leaking from the bearing cavity seal assembly into the engine disk cavity and protect the bearing and lubricating oil from the damage of the high-temperature gas environment.

[0003] While effectively sealing the lubricating oil in the bearing cavity, a certain amount of air will inevitably enter the bearing cavity through the gaps between the sealing structures and mix with the lubricating oil to form an oil-gas mixture. The oil-gas mixture in the bearing cavity containing bubbles will lead to a decrease in the bearing lubrication effect, an increase in the lubricating oil pressure in the bearing cavity, and a reduction in the sealing margin. Since too much air in the bearing cavity will cause increased bearing wear and lubricating oil leakage, seriously threatening the safe and reliable operation of the engine, a ventilation system needs to be designed to ensure that the pressure in the bearing cavity meets the requirements.

[0004] The existing ventilation design of the lubricating oil system of gas turbine engines is as Figure 1 shown. Usually, the axial ventilation is realized by using a hollow engine shaft 101. Compared with the throttle ventilation and free ventilation systems, axial ventilation can eliminate accessories such as external ventilation pipes and centrifugal ventilators, 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 arranged 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 central cone 103 and the engine tail cone 105, due to the heat radiation of the high-temperature gas B between the central cone 103 and the inner annulus nozzle 104 and the heat conduction of the central cone 103, problems such as lubricating oil coking and ignition are likely to occur in the tail cone cavity 28. At the same time, the outlet of the independent axial ventilation flow path is located at the engine tail cone outlet, and the pressure fluctuates greatly under the influence of the unsteady mainstream at the nozzle outlet, resulting in a large error in the flow path design result, making the actual ventilation flow path not meet the design requirements and having a poor ventilation effect. Summary of the Invention

[0005] In order to solve the technical problems that the existing axial ventilation system is prone to lubricating oil coking and ignition in the tail cone cavity and has a poor ventilation effect, the present invention discloses a flow path system that couples the axial ventilation of the bearing cavity and the ventilation of the turbine disk cavity. The flow path system includes:

[0006] A compressor shaft, one end of which is sleeved on the fan shaft and the other end is sleeved on the turbine shaft;

[0007] The front bearing cavity and the rear bearing cavity, where the front bearing cavity is formed by the intermediate casing, the fan shaft, and the front end of the compressor shaft, and the rear bearing cavity is formed by the combustion chamber casing, the turbine shaft, and the rear end of the compressor shaft. The front bearing cavity is in fluid communication with the axial flow path of the fan shaft, and the rear bearing cavity is in fluid communication with the axial flow path of the turbine shaft. At the end of the axial flow path of the turbine shaft in the airflow direction, there is an oil and gas ventilation pipe, and the inner walls of the hollow axial centers of the compressor shaft, the fan shaft, the turbine shaft, and the inner wall of the oil and gas ventilation pipe enclose an axial ventilation flow path for the bearing cavity;

[0008] The end journal of the turbine shaft, the outer wall of the oil and gas ventilation pipe, and the turbine disk enclose a ventilation flow path for the center of the turbine disk. The oil and gas mixture in the axial ventilation flow path of the bearing cavity is mixed with the cooling air in the ventilation flow path for the center of the turbine disk and then discharged into the main flow path.

[0009] Further, a first through hole is provided on the fan shaft. The first through hole penetrates the fan shaft radially 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. The second through hole penetrates the turbine shaft radially to connect the rear bearing cavity with the axial flow path of the turbine shaft. The fan shaft, the turbine shaft, and the compressor shaft are all hollow structures and their axes coincide.

[0010] Further, a fulcrum bearing seat, a fulcrum bearing, and a fulcrum seal assembly are provided between the compressor shaft and the intermediate casing and between the compressor shaft and the combustion chamber casing respectively.

[0011] Further, a ventilation hole is provided on the end journal of the turbine shaft, and cooling air flows into the ventilation flow path for the center of the turbine disk through the ventilation hole.

[0012] Further, the turbine disk includes a first-stage turbine disk and a second-stage turbine disk. An interval ring is provided between the first-stage turbine disk and the second-stage turbine disk. A rotating cavity is formed among the first-stage turbine disk, the second-stage turbine disk, and the interval ring, and the rotating cavity is in communication with the ventilation flow path for the center of the turbine disk.

[0013] Even further, a concave cavity is provided at a low radius on the front side of the second-stage turbine disk.

[0014] Further, the oil and gas ventilation pipe includes a front straight pipe section, a middle tapered pipe section, and a rear straight pipe section. The diameter of the front straight pipe section is larger than that of the rear straight pipe section, so as to form a tapered circular pipe structure along the airflow direction.

[0015] Even further, the front straight pipe section is located near the axial center on the front end of the end journal of the turbine shaft, and the rear straight pipe section is located at the axial center position below the center of the turbine disk.

[0016] Further, a blower wheel in the shape of a disc is provided between the second-stage turbine disc of the turbine disc and the tail cone cavity. The oil-gas mixture in the axial ventilation flow path of the bearing cavity and the cooling air in the ventilation flow path of the turbine disc center are mixed at the front root of the blower wheel and then discharged radially into the main flow path through the cavity between the blower wheel and the rear side of the second-stage turbine disc.

[0017] Further, an axial gap is provided between the end of the lubricating oil ventilation pipe and the blower wheel. The cooling air entering the ventilation flow path of the turbine disc center draws out the oil-gas mixture in the axial ventilation flow path of the bearing cavity through the axial gap and mixes them.

[0018] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above technical solutions adopted in the embodiments of this specification at least include: The flow path system of the present invention can effectively improve the ventilation effect of the bearing cavity axis. The air in the ventilation flow path of the turbine disc cavity draws the oil-gas mixture in the axial ventilation flow path, mixes the cooling air and the oil-gas mixture for cooling, and then discharges it into the main flow path through the low-temperature area under the action of pressure difference and the centrifugal force of the turbine disc and the blower wheel, avoiding the medium containing the oil-gas mixture from flowing through the high-temperature area of the tail cone cavity and solving the problems of lubricating oil coking and ignition.

[0019] Compared with the existing ventilation structure, the structure of the present invention is simple and the flow path system coupling design can achieve different functions and has a flexible adjustment method; through the flow path system coupling the axial ventilation of the bearing cavity and the ventilation of the turbine disc center, the high-speed flow in the turbine disc center draws out the low-speed oil-gas mixture from the axis through the entrainment suction effect, and then fully mixes and cools with the cooling air and flows into the main flow path through the low-temperature area under the action of pressure difference and the centrifugal force of the turbine disc, which not only effectively solves the problems of lubricating oil coking and ignition, but also improves the ventilation effect of the bearing cavity 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 eliminate components such as oil-gas separators and external ventilation pipes, contributing to the weight reduction and cost reduction of the engine. Description of the Drawings

[0020] 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 in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0021] Figure 1 It is a schematic diagram of the ventilation flow of an existing gas turbine engine;

[0022] Figure 2 It is a schematic diagram of the flow path system coupling the axial ventilation of the bearing cavity and the ventilation of the turbine disc cavity disclosed in the embodiments of the present invention;

[0023] Among them, 101 is the engine shaft; 102 is the baffle; 103 is the center cone; 104 is the inner nozzle; 105 is the engine tail cone; 1 is the front bearing cavity; 2 is the rear bearing cavity; 3 is the fan shaft; 31 is the first through hole; 4 is the turbine shaft; 41 is the second through hole; 42 is the ventilation hole; 43 is the end journal of the turbine shaft; 5 is the tension bolt; 6 is the fan disk; 7 is the first support seal assembly; 8 is the first support bearing; 9 is the first support bearing housing; 10 is the intermediate casing; 11 is the second support bearing housing; 12 is the second support bearing; 13 is the second support seal assembly; 14 is the compressor shaft; 15 is the third support seal assembly; 16 is the third support bearing housing; 17 is the third support bearing; 18 is the combustion chamber casing; 19 is the fourth support bearing housing; 20 is the fourth support bearing; 21 is the fourth support seal assembly; 22 is the first stage turbine disk; 23 is the spacer ring; 24 is the second stage turbine disk; 25 is the guide vane wheel; 26 is the lubricating oil ventilation pipe; 27 is the rotating cavity; 28 is the tail cone cavity; 29 is the concave cavity; 100 is the bearing cavity central ventilation flow path; 200 is the turbine disk central ventilation flow path. Specific implementation manners

[0024] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0025] The following uses specific specific examples to illustrate the implementation manners of the present application. 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 of the embodiments. The present application can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, without conflict, the following embodiments and the features of the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts fall within the scope of protection of the present application.

[0026] In the description of this embodiment, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0027] In addition, terms such as "first", "second", "third", etc. are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", etc. may explicitly or implicitly include one or more features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0028] It should also be noted that the diagrams provided in the following embodiments only schematically illustrate the basic concept of the present disclosure. The diagrams only show the components related to the present disclosure and are not drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and proportion of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0029] An embodiment of the present invention discloses a flow path system for coupling the axial ventilation of the bearing cavity and the ventilation of the turbine disk cavity. This flow path system can solve the technical problems that the axial ventilation of the bearing cavity is prone to lubricating oil coking and ignition when exhausting from the tail cone cavity 28 of the tail cone, and the large lubricating oil consumption due to poor ventilation effect. 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 core ventilation flow path 200, etc.

[0030] Specifically, referring to 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 axis is hollow and provided with a flow path channel). 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 rear end of the compressor shaft 14.

[0031] 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. 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 communicated with the axial flow path of the fan shaft. The rear bearing cavity 2 is communicated with the axial flow path of the turbine shaft. A lubricating oil ventilation pipe 26 is provided at the end of the axial flow path of the turbine shaft along the air flow direction. The inner walls of the axial center of the compressor shaft, the axial center of the fan shaft, the axial center of the turbine shaft, and the inner wall of the lubricating oil ventilation pipe 26 enclose the bearing cavity axial ventilation flow path 100.

[0032] Among them, referring to Figure 2 As shown, the end journal 43 of the turbine shaft, the outer wall of the lubricating oil ventilation pipe 26, and the turbine disk enclose the turbine disk core ventilation flow path 200. The oil-gas mixture in the bearing cavity axial ventilation flow path 100 is mixed with the cooling air in the turbine disk core ventilation flow path 200 and then discharged into the main flow path.

[0033] Further, referring to Figure 2 As shown, a first through hole 31 is provided on the fan shaft 3. The first through hole 31 penetrates the fan shaft 3 in the radial direction to communicate the front bearing cavity 1 with the axial flow path of the fan shaft. A second through hole 41 is provided on the turbine shaft 4. The second through hole 41 penetrates the turbine shaft 4 in the radial direction to communicate the rear bearing cavity 2 with the axial flow path of the turbine shaft. The axes 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 8 mm, the diameter of the second through hole 41 can be set to 5 mm, the number of them can be set to one or more along 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 in the middle section.

[0034] Further, a fulcrum bearing seat, a fulcrum bearing, and a fulcrum seal assembly are provided between the compressor shaft 14 and the intermediate casing 10 and the combustion chamber casing 18, respectively. Specifically, referring to Figure 2 As shown, a second fulcrum bearing seat 11, a second fulcrum bearing 12, and a second fulcrum seal assembly 13 are provided between the front end of the compressor shaft 14 and the intermediate casing 10. A third fulcrum bearing seat 16, a third fulcrum bearing 17, and a third fulcrum seal 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 seal 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. The front end of the fan shaft 3 is connected to the fan disk 6 through a tension bolt 5. At the same time, a fourth fulcrum bearing seat 19, a fourth fulcrum bearing 20, and a fourth fulcrum seal assembly 21 are provided between the rear end of the combustion chamber casing 18 and the rear end of the turbine shaft 4.

[0035] Further, referring to Figure 2 As shown, a ventilation hole 42 is provided on the end shaft neck 43 of the turbine shaft. Cooling air flows into the ventilation flow path of the turbine disk center through the ventilation hole 42. The turbine disk includes 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. A rotating cavity 27 is formed among the first-stage turbine disk 22, the second-stage turbine disk 24, and the spacer ring 23. The rotating cavity 27 is communicated with the ventilation flow path of the turbine disk center.

[0036] During specific implementation, the cooling air in the ventilation flow path 200 of the turbine disk core flows into the turbine disk cavity through the vent holes 42 on the journal 43 at the end of the turbine shaft. 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, a large vortex is formed in the cooling air in the rotating cavity 27 at the low radius of the rotating cavity. Another part of the cooling air is affected by the vortex at the low radius of the cavity, the actual flow area decreases, the flow velocity increases, and it continues to accelerate backward along the core of the second-stage turbine disk 24. At the outlet of the core of the second-stage turbine disk 24, the oil-gas mixture in the lubricating oil ventilation pipe 26 is sucked out through the entrainment effect. After the cooling air is mixed with the oil-gas mixture and cooled down, it flows towards the high radius under the pressure difference and centrifugal action, and finally is discharged into the main flow path through the low-temperature cavity area between the second-stage turbine disk 24 and the air guide wheel 25.

[0037] In an improved embodiment, referring to Figure 2 As shown, a concave cavity 29 is provided at the low radius on the front side of the second-stage turbine disk 24. The air flow in the rotating cavity 27 forms a large eddy under the disturbance of the concave cavity 29, squeezing the actual flow area of the core of the second-stage turbine disk 24. The flow area of the turbine disk core decreases along the air flow direction, and the actual flow channel is of a contraction type, so that the air flow in the core accelerates.

[0038] Further, referring to Figure 2 As shown, the lubricating oil ventilation pipe 26 includes a front straight pipe section, a middle gradually tapered pipe section, and a rear straight pipe section. The diameter of the front straight pipe section is larger than that of the rear straight pipe section, and thus a gradually tapered circular pipe structure along the air flow direction can be formed. Specifically, the front straight pipe section is located near the axis on the front end of the journal 43 at the end of the turbine shaft, and the rear straight pipe section is located at the axis position below the core of the turbine disk.

[0039] Further, referring to Figure 2 As shown, an air guide wheel 25 in the shape of a disk is provided between the second-stage turbine disk 24 of the turbine disk and the tail cone cavity 28. The middle part in the radial direction of the air guide wheel 25 is connected to the second-stage turbine disk 24 through circumferentially distributed bolts. The air guide wheel 25 can separate the tail cone cavity 28 from the axial ventilation flow path 100 of the bearing cavity and the ventilation flow path 200 of the turbine disk core in front of it, preventing the gas in the two flow paths from flowing into the tail cone cavity 28, so that the oil-gas mixture in the axial ventilation flow path 100 of the bearing cavity and the cooling air in the ventilation flow path 200 of the turbine disk core are mixed at the root on the front side of the air guide wheel 25 and then discharged into the main flow path radially through the cavity between the air guide wheel 25 and the rear side of the second-stage turbine disk 24.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] Obviously, those skilled in the art should understand that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, various changes and modifications can be made to the embodiments of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

[0045] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments 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; 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); the rotating cavity (27) is communicated with the turbine disc core ventilation flow path (200); a concave cavity (29) is provided at a low radius on the front side of the second-stage turbine disc (24); An air guide wheel (25) of a disc-shaped structure is provided between the second-stage turbine disk (24) 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 central 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); an axial gap is provided between the end of the lubricating oil ventilation pipe (26) and the air guide wheel (25); the cooling air entering the turbine disk central ventilation flow path (200) guides the oil-gas mixture of the bearing cavity axial ventilation flow path (100) out through the axial gap and mixes the mixture.

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 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.

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: 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.

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