High pressure turbine area bearing cavity arrangement and method of cooling its vent tube

Abstract

The high-pressure turbine region bearing cavity arrangement facilitates reducing the temperature of the inner wall surface of the bearing cavity vent pipe, including a seal air cavity for the flow of seal air around the periphery of the bearing cavity, a vent pipe for venting seal air leaking into the bearing cavity to the outside of the bearing cavity, and a vent pipe mount for mounting the vent pipe and communicating the vent pipe with the bearing cavity; wherein the vent pipe mount passes through the seal air cavity, and the vent pipe mount is provided with vent holes around the junction of the vent pipe to vent the seal air flow from the vent holes. The vent pipe cooling method of the high-pressure turbine region bearing cavity arrangement can reduce the heating temperature of the vent pipe.

Description

TECHNICAL FIELD

[0001] The present application relates to a high-pressure turbine region bearing cavity device of an aero-engine or a gas turbine and a ventilation pipe cooling method thereof. BACKGROUND

[0002] The front and rear seals of the bearing cavity in the high-temperature region of the high-pressure turbine of an aero-engine or a gas turbine adopt a labyrinth seal, and a ventilation pipe needs to be arranged to discharge the seal gas leaked into the bearing cavity to the outside of the bearing cavity. The bearing cavity ventilation pipe is in a very hot environment.

[0003] The patent application with the publication number "CN 114294112 A" discloses that an aero-engine bearing cavity is generally composed of a bearing cavity shell, a bearing, a sealing device, a lubricating oil supply and return pipe, and a ventilation pipe, etc. The bearing cavity pipeline is a single-layer structure, and the outer wall thereof is wrapped with a thermal insulation material and a skin, but such a bearing cavity pipeline thermal insulation structure is difficult to effectively meet the increasingly high peripheral working environment of the bearing cavity, and thus a double-channel pipeline device with a switching sealing structure is proposed to achieve the purposes of pipeline thermal insulation and rapid cooling.

[0004] The inner wall surface temperature can be reduced by designing the ventilation pipe into a double-layer pipe wall and injecting cooling lubricating oil into the ventilation pipe. However, only these two methods cannot reduce the inner wall surface temperature of the ventilation pipe to below 204℃, and the lubricating oil in the ventilation pipe will be severely coked or even ignited, affecting the performance of the lubricating oil, so it is still necessary to continue to reduce the inner wall surface temperature of the ventilation pipe. SUMMARY

[0005] The present application aims to provide a high-pressure turbine region bearing cavity device which is beneficial to reduce the temperature of the inner wall surface of the bearing cavity ventilation pipe.

[0006] Another object of the present application is to provide a ventilation pipe cooling method of a high-pressure turbine region bearing cavity device.

[0007] According to the high-pressure turbine region bearing cavity device of one aspect of the present application, a seal gas flow for the peripheral bearing cavity is provided with a seal gas inducing cavity, a ventilation pipe for discharging the seal gas leaked into the bearing cavity to the outside of the bearing cavity, and a ventilation pipe mounting seat for mounting the ventilation pipe and connecting the ventilation pipe with the bearing cavity; wherein the ventilation pipe mounting seat penetrates through the seal gas inducing cavity, and ventilation holes are arranged around the connection of the ventilation pipe on the ventilation pipe mounting seat to discharge the seal gas flow from the ventilation holes.

[0008] In one embodiment, the ventilation holes are annular holes around the connection of the ventilation pipe on the mounting seat.

[0009] In one embodiment, the connection of the ventilation pipe on the mounting base is provided by a boss, and the mounting base further comprises a ring wall surrounding the boss, and the ventilation hole is arranged between the ring wall and the boss.

[0010] In one embodiment, the ring wall is higher than the boss.

[0011] In one embodiment, the sealing air flow in the sealing air flow cavity is arranged to be discharged only through the ventilation hole.

[0012] In one embodiment, the flow passage cross-sectional area of at least a part of the ventilation pipe gradually decreases from inside to outside on the engine.

[0013] In one embodiment, the ventilation pipe is a double-layer pipe wall.

[0014] In one embodiment, the cross section of any layer of the pipe wall has a long axis.

[0015] According to another aspect of the high-pressure turbine area bearing cavity device ventilation pipe cooling method of the present application, the sealing air flow of the sealing air flow cavity is used to cool the connection of the ventilation pipe on the mounting base, so that the temperature of the connection of the ventilation pipe on the mounting base is 80-100 degrees Celsius lower than the temperature of the peripheral cavity of the sealing air flow cavity.

[0016] In one embodiment, the cross section of at least a part of the inner wall of the ventilation pipe is designed to be tapered, i.e., gradually decreases from inside to outside on the engine, so that the flow rate of the oil-gas mixture in the ventilation pipe gradually increases, accelerating convective heat transfer, thereby reducing the inner wall surface temperature of the ventilation pipe.

[0017] According to the embodiment of the present application, by reducing the wall surface temperature of the ventilation pipe connection, conducting heat transfer, and increasing the flow rate of the oil-gas mixture in the ventilation pipe to accelerate heat exchange, the inner wall surface temperature of the ventilation pipe is reduced, thereby avoiding coking or ignition of the lubricating oil in the ventilation pipe, and reducing the risk of spontaneous combustion of the lubricating oil pipeline. BRIEF DESCRIPTION OF DRAWINGS

[0018] The above and other features, properties, and advantages of the present application will become more apparent by describing in detail the following embodiments with reference to the accompanying drawings and examples, in which:

[0019] Figure 1 is a sectional view of a high-pressure turbine area bearing cavity device as a comparative example;

[0020] Figure 2 is a partial view of a high-pressure turbine area bearing cavity device as a comparative example;

[0021] Figure 3 is a flow direction schematic diagram of a sealing air flow of a high-pressure turbine area bearing cavity device as a comparative example;

[0022] Figure 4 is a cross-sectional view of a high-pressure turbine region bearing cavity device according to an embodiment of the present application;

[0023] Figure 5 is a partial view of a high-pressure turbine region bearing cavity device according to an embodiment of the present application;

[0024] Figure 6 is a cross-sectional view of a ventilation pipe of a high-pressure turbine region bearing cavity device as a pair of alternatives;

[0025] Figure 7 is a cross-sectional view of a ventilation pipe of a high-pressure turbine region bearing cavity device according to an embodiment of the present application;

[0026] Figure 8 is a cross-sectional view of a ventilation pipe according to an embodiment of the present application. DETAILED DESCRIPTION

[0027] Reference will now be made in detail to embodiments of the application, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the application, not limitation of the application. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present application without departing from the scope or spirit of the application. For instance, features illustrated or described as part of one embodiment, can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present application covers modifications and variations of this application provided they come within the scope of the appended claims and their equivalents.

[0028] As used herein, the terms "first", "second" and "third" can be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components.

[0029] The terms "upstream" and "downstream" refer to the relative direction with respect to fluid flow in a fluid path. For example, "upstream" refers to the direction from which the fluid flows, and "downstream" refers to the direction to which the fluid flows.

[0030] corresponding Figure 1 the cut position of Figure 2 the ventilation pipe 11 in Figure 3 the cut position of Figure 2 the ventilation hole 12 in

[0031] As Figure 1As shown, the high-pressure turbine area bearing cavity assembly includes a bearing housing 1, a front gas seal 2, a front oil seal 3, a front oil grate 4, a bearing 5, an oil catch ring 6, an oil supply assembly 7, a rear oil grate 8, and a rear seal seat 9. These components surround and form a bearing cavity 40, outside of which is a sealed bleed chamber 30. Ventilation pipes 11 are connected at the upper part of the bearing cavity 40. In one example, there are ventilation pipes 11 at the 2 o'clock and 10 o'clock positions along the heading, each connected to a ventilation pipe mounting base 20 on the rear seal seat 9 by bolts 10.

[0032] The sealing air duct 30 is used to supply the sealing airflow around the bearing cavity. Figure 3 As shown more specifically, the areas through which the sealing airflow indicated by the arrows flows are all included in the sealing venting chamber 30. The ventilation duct 11 in the high-pressure turbine bearing cavity assembly is used to vent the sealing air that leaks into the bearing cavity 40 to the outside of the bearing cavity 40, and the ventilation duct mounting base 20 is used to install the ventilation duct 11 and connect the ventilation duct 11 to the bearing cavity 40.

[0033] In this comparative example, in order to reduce the temperature inside the bearing cavity, multiple ordinary ventilation holes 12 are opened on the rear seal seat 9 to accelerate the flow rate of the sealing gas. Figure 3 The middle arrow indicates the direction of airflow. Part of the air inside the sealed venting chamber enters the outer cavity through the ordinary ventilation hole 12. Figure 1 It can be understood that the connection of the ventilation pipe 11 on the ventilation pipe mounting base 20 is actually located in the outer cavity.

[0034] The embodiments of the present invention are improvements based on this comparative example. Figure 4 , Figure 5 , and 7 and Figure 8 Such an embodiment is shown. Corresponding Figure 4 The cutting position passes laterally. Figure 5 The ventilation duct 11 is shown. (As shown) Figure 4 As shown, the ventilation duct mounting base 20 passes through the sealed air intake chamber 30, and a ventilation hole 13 is provided on the ventilation duct mounting base 20 around the connection 21 of the ventilation duct 11, so that the sealed airflow can be discharged from the ventilation hole 13. The ventilation hole 13 at the connection 21 of the ventilation duct not only realizes the function of the ordinary ventilation hole 12 to accelerate the sealed airflow velocity, but also reduces the wall temperature at the connection of the ventilation duct 11. The thermal analysis boundary condition of the wall at the connection of the ventilation duct 11 changes from the temperature of the outer cavity to the temperature of the sealed air intake chamber, which can usually reduce the temperature by 80℃ to 100℃. This reduces the wall temperature at the connection of the ventilation duct, and through heat conduction, it can reduce the temperature of the inner wall of the ventilation duct.

[0035] In one embodiment, the vent 13 is an annular hole surrounding the connection 21 of the vent duct 11 on the mounting base 20. This allows for further cooling at every point around the connection 21.

[0036] like Figure 4 As shown, the connection 21 of the ventilation duct 11 on the mounting base 20 is provided by a boss 201. The mounting base 20 also includes an annular wall 202 surrounding the boss, and a ventilation hole 13 is provided between the annular wall 202 and the boss 201. The annular wall 202 can further isolate the outer cavity and seal the air duct cavity, thereby increasing the cooling effect.

[0037] like Figure 4 As shown, the annular wall 202 should be higher than the boss 201 so that the connection 21 is completely in the sealed air duct, thus fully reducing its heating temperature.

[0038] Optionally, the sealed air duct is configured such that the sealed airflow can only be discharged through the ventilation hole 13, and apart from the ventilation hole 13, there are almost no ventilation holes 12 as described in the comparative example. This further enhances the airflow and cooling effect of the ventilation hole 13, reduces the ventilation area of ​​ordinary ventilation holes in other locations at the top of the sealed air duct, and prevents thermal stress concentration.

[0039] The outer wall of the ventilation pipe is directly under the radiation of the high-temperature support plate. When the engine or gas turbine is normally running, the temperature of the high-temperature support plate after the turbine can be as high as 1000°C or above. The ventilation pipe around the center is directly under the strong thermal radiation of the high-temperature support plate, causing the outer surface temperature of the ventilation pipe to be nearly 500-600°C. At the same time, the engine case wall connected to the ventilation pipe will also directly transfer heat to the local surface of the ventilation pipe through heat conduction, thereby causing the local overheating of the pipe. Therefore, under the action of high-temperature support plate thermal radiation and engine case heat conduction, the outer surface of the ventilation pipe always maintains a relatively high temperature. The high temperature of the outer surface of the ventilation pipe will further be transferred to the inner layer of the ventilation pipe, causing the temperature of the inner wall of the pipe to rise sharply. After the oil-gas mixture in the ventilation pipe of the bearing cavity flows through the high-temperature wall, the oil-gas mixture may cause the wall to coke, and even may cause the oil-gas mixture to self-ignite in the pipe, causing damage to the engine or gas turbine. The flow pattern of the oil-gas mixture in the ventilation pipe of the bearing cavity is an upward annular flow pattern. In this flow pattern, the liquid film on the pipe wall is thick and contains oil bubbles, and the core part of the pipe is still mainly gas. Therefore, the heat exchange capacity of the pipe based on this flow pattern is closely related to the proportion of the oil-gas mixture in the pipe, the flow rate of the oil-gas mixture, and the gas content in the oil. From the aspect of the flow rate of the oil-gas mixture, when the flow rate in the pipe is fast, the heat in the inner wall of the pipe can be effectively taken away, thereby reducing the temperature of the inner wall of the pipe, and thus reducing the risk of oil coking, but at the same time, a large amount of heat is transferred to the oil, causing the thermal load of the entire oil system to rise. When the flow rate in the pipe is slow, the heat exchange capacity in the pipe is weakened, causing the temperature of the wall of the pipe to rise, the possibility of oil coking to increase, and even the risk of self-ignition of the oil pipe to exist. In addition, the bearing cavity inlet conditions such as the oil supply amount and the air leakage amount also affect the proportion of the oil-gas mixture in the pipe. Further, these factors also affect the heat exchange in the pipe.

[0040] As shown in Figure 7 , at least a portion 15 of the flow passage cross-sectional area of the ventilation pipe gradually decreases from the inside to the outside of the engine. In comparison, as shown in Figure 6 , at least a portion 14 of the flow passage cross-sectional area of the ventilation pipe remains almost unchanged from the inside to the outside of the engine. According to embodiments of the present application, the flow rate of the oil in the ventilation pipe gradually increases, so the convective heat transfer can be accelerated, thereby reducing the temperature of the inner wall of the ventilation pipe, reducing the risk of oil coking and pipe natural risk.

[0041] As shown in Figure 8 , the ventilation pipe is a double-layer pipe wall. Alternatively, either layer 15a, 15b of the pipe wall has an elongated cross-section. In other embodiments, the cross-section of the inner wall of the ventilation pipe can be various shapes, such as a waist shape, a circular shape, etc.

[0042] In combination with the foregoing embodiments, it can be understood that the ventilation pipe cooling method uses the sealing air flow of the sealing air cavity to cool the connection of the ventilation pipe on the mounting seat, so that the temperature of the connection of the ventilation pipe on the mounting seat is 80-100 degrees Celsius lower than the temperature of the peripheral cavity of the sealing air cavity.

[0043] Further, at least a portion of the cross section of the inner wall of the ventilation pipe is designed to be tapered, that is, gradually reduced from inside to outside on the engine, so that the flow rate of the oil gas mixture in the ventilation pipe is gradually increased, the convective heat transfer is accelerated, and the inner wall surface temperature of the ventilation pipe is reduced.

[0044] Although the present application is disclosed with the preferred embodiments as above, it is not intended to limit the present application, and any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, which does not deviate from the technical solutions of the present application, falls within the protection scope defined by the claims of the present application.

Claims

1. A high pressure turbine area bearing cavity arrangement comprising: a seal air cavity for a seal air flow around a bearing cavity, a vent tube for venting seal air leaking into the bearing cavity out of the bearing cavity, and a vent tube mount for mounting the vent tube and communicating the vent tube with the bearing cavity; characterized in that the vent tube mount passes through the seal air cavity and the vent tube mount is provided with vent holes around the junction of the vent tube on the vent tube mount to vent the seal air flow from the vent holes.

2. The high pressure turbine area bearing cavity arrangement of claim 1, wherein, the vent holes are annular holes around the junction of the vent tube on the mount.

3. A high pressure turbine area bearing cavity arrangement according to claim 1 or 2, characterised in that, the junction of the vent tube on the mount is provided by a boss and the mount further comprises an annular wall around the boss with the vent holes between the annular wall and the boss.

4. The high pressure turbine area bearing cavity arrangement of claim 3, wherein, the annular wall is higher than the boss.

5. The high pressure turbine area bearing cavity arrangement of claim 1, wherein, the seal air cavity is arranged so that the seal air flow therein can only be vented through the vent holes.

6. The high pressure turbine area bearing cavity arrangement of claim 1, wherein, the flow passage cross sectional area of at least a portion of the vent tube tapers from inside to outside on the engine.

7. The high pressure turbine area bearing cavity arrangement of claim 1 or 5, wherein the vent tube is a double walled tube.

8. The high pressure turbine area bearing cavity arrangement of claim 7, wherein, the cross section of either wall of the tube has a major axis.

9. The method of vent tube cooling of a high pressure turbine area bearing cavity arrangement according to any one of claims 1 to 8, characterized in that, the seal air flow of the seal air cavity is used to cool the junction of the vent tube on the mount so that the junction of the vent tube on the mount is 80-100 degrees Celsius cooler than the temperature of the outer cavity of the seal air cavity.

10. The method of duct cooling of claim 9, wherein, the cross section of at least a portion of the inner wall of the vent tube is tapered, i.e. tapers from inside to outside on the engine, so that the flow velocity of the oil gas mixture in the vent tube increases, increasing convective heat transfer and thus reducing the temperature of the inner wall of the vent tube.

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