Bearing cavity sealing air independent supercharging structure and engine thereof

Abstract

The application discloses a bearing cavity sealing air self-pressurization structure and an engine thereof, and belongs to the technical field of aero-engines and gas turbines. The structure comprises a casing, a sealing bush and a compression blade group. The sealing bush is a stepped cylinder and is arranged in the central hole of the casing to form an annular channel. The compression blade group comprises at least one axial compression unit and one centrifugal compression unit. The rectifying blades and rotor blades of the axial compression unit are arranged on the casing and the sealing bush respectively; the centrifugal rotor blades of the centrifugal compression unit are arranged on the radial section of the sealing bush. A sealing device is arranged downstream of the airflow outlet, and the other side of the sealing device is an oil cavity. The sealing bush rotates with the shaft to drive the rotor blades to compress and expand the bleed air, thereby greatly improving the static pressure before the sealing device. The application solves the problem of insufficient static pressure before the sealing in the prior art, does not need a bleed air conversion device, has small bleed air quantity and reliable sealing.

Description

Technical Field

[0001] This invention relates to the field of aero-engine and gas turbine technology, and in particular to a bearing cavity sealing and bleed air self-pressurization structure and its engine. Background Technology

[0002] In aero-engines and gas turbines, bearings are critical rotating support components, and their reliability and service life directly affect the overall performance and flight safety. Bearings typically operate under high temperature, high speed, and heavy load conditions, making proper lubrication essential for reducing friction, suppressing temperature rise, and preventing wear. However, while achieving efficient lubrication, preventing oil leakage from the bearing cavity remains another key challenge.

[0003] In existing technologies, structures such as grate seals, graphite seals, or brush seals are typically installed between the oil chamber and the air chamber. However, relying solely on the sealing structure is insufficient to completely prevent leakage. Therefore, the oil seal bleed air technology has been developed: a high-pressure air stream is introduced from the engine compression system (fan or compressor) and enters the air chamber outside the sealing structure, creating a pressure higher than that in the oil chamber, thereby preventing oil leakage.

[0004] However, the pressure differences between the various stages of the engine's compression system vary significantly under different operating conditions. At idle or high altitude, the pressure in the earlier stages is low, requiring bleed air from the later stages; at low altitude and high speed, the pressure and temperature in the later stages are too high, necessitating a switch back to the earlier stages. Traditional designs have therefore resorted to complex bleed air conversion devices. These devices not only increase the weight of accessories and the complexity of piping but also introduce the risk of conversion failure. More critically, even with a bleed air conversion device, the gas drawn from the compression system experiences significant static pressure loss after passing through long pipes and throttling elements, especially at low speeds. The static pressure of the sealing gas before entering the sealing device remains severely insufficient, making it difficult to establish a reliable and stable sealing pressure differential, resulting in a persistently high risk of lubricating oil leakage. Simultaneously, a large bleed air volume significantly impacts the efficiency of the compression system. Therefore, how to effectively increase the static pressure of the sealing gas before entering the sealing device without relying on complex bleed air conversion and without consuming large amounts of mainstream gas has become a pressing technical challenge in this field. Summary of the Invention

[0005] The main objective of this invention is to propose a bearing cavity sealing gas priming and pressurization structure to solve the technical problem of insufficient static pressure of sealing gas before entering the sealing device in the prior art, especially the difficulty in establishing a reliable sealing pressure difference under low-speed conditions.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention proposes a bearing cavity sealing bleed air self-pressurization structure, comprising: a casing; a sealing bushing, the sealing bushing being disposed in the central hole of the casing and coaxially arranged to form an annular airflow channel; the sealing bushing having a stepped cylindrical structure; and a compression blade assembly disposed within the annular airflow channel; the compression blade assembly comprising at least one axial-flow compression unit and one centrifugal compression unit; each axial-flow compression unit comprising rectifier blades and rotor blades arranged sequentially along the axial direction, the rectifier blades being mounted on the casing and the rotor blades being mounted on the sealing bushing; the centrifugal compression unit comprising centrifugal rotor blades, the centrifugal rotor blades being mounted on the radial section of the sealing bushing; a sealing device being disposed downstream of the airflow outlet of the compression blade assembly, the other side of the sealing device being an oil chamber; wherein, the sealing bushing rotates with the engine shaft, driving the rotor blades and centrifugal rotor blades to rotate, thereby compressing and diffused the sealing bleed air.

[0007] Furthermore, the compression blade assembly includes a two-stage axial flow compression unit and a one-stage centrifugal compression unit.

[0008] Furthermore, the number of rectifier blades and rotor blades in each stage of the axial flow compression unit is determined according to the diameter of the sealing bushing, and the blade consistency is 0.5 to 2.

[0009] Furthermore, the angle between the rectifier blade and the rotor blade relative to the axial direction is 30° to 60°; the angle between the outlet direction of the centrifugal rotor blade and the radial direction is 30° to 60°.

[0010] Furthermore, the sealing air intake originates from the fixed position of the fan, the fixed position of the compressor component, or the atmospheric environment.

[0011] Furthermore, the total boost ratio of the compression blade assembly in the engine idle state is not less than 5.

[0012] Furthermore, along the air intake direction, the sealing bushing sequentially includes a first cylindrical section, the radial section, and a second cylindrical section; the casing is also a stepped cylindrical structure, sequentially including a first cylindrical body, a first radial ring, a second cylindrical body, a second radial ring, and a third cylindrical body along the air intake direction; the two-stage axial flow compression unit includes a first-stage rectifier blade and a first-stage rotor blade; as well as a second-stage rectifier blade and a second-stage rotor blade; both the first-stage rectifier blade and the second-stage rectifier blade are mounted on the inner wall of the first cylindrical body of the casing; both the first-stage rotor blade and the second-stage rotor blade are mounted on the outer wall of the first cylindrical section of the sealing bushing.

[0013] Furthermore, the compression blade assembly also includes a third-stage rectifier blade, which is installed on the inner wall of the second cylinder of the casing; the third-stage rectifier blade has a rectangular blade shape and is parallel to the axial direction of the casing, which is used to stop the sealing bleed in the circumferential direction.

[0014] Furthermore, the sealing device is a graphite sealing structure; the sealing device is sleeved on the second cylindrical section of the sealing bushing and located in the third cylindrical body of the casing.

[0015] Secondly, the present invention also proposes an aero-engine or gas turbine, including the aforementioned bearing cavity sealing and bleed air self-pressurization structure.

[0016] By applying the technical solution of this invention, axial-centrifugal combined compression blades are arranged between the casing and the sealing bushing along the path of the bleed air in the bearing cavity sealing. The rotational energy of the engine shaft itself is used to perform multi-stage compression and diffusion of the bleed air, significantly increasing the static pressure of the sealing gas before it enters the sealing device. Compared with the prior art, this solution has the following beneficial technical effects: (1) Significantly improves the static pressure before sealing and ensures sealing reliability: Through the multi-stage compression and diffusion of the axial-centrifugal combined stage, especially the stagnation effect of the last stage axial parallel rectifier blades, the static pressure of the sealing gas before entering the sealing device is greatly improved. Even under low-speed conditions such as engine idle, the total pressure ratio can be guaranteed to be no less than 5, thereby forming a stable and sufficient sealing pressure difference on both sides of the sealing device, effectively solving the problem of insufficient sealing pressure under low-speed conditions.

[0017] (2) Simplify system structure and eliminate conversion risk: This self-pressurization structure no longer needs to draw air from the high-pressure stage of the compression system, nor does it need to set up a complex air bleed conversion device, which significantly reduces engine accessories and pipelines and fundamentally eliminates the risk of air bleed conversion function failure.

[0018] (3) Reduce bleed air volume and improve engine efficiency: The sealing bleed air position is flexible and can draw air directly from a fixed low-pressure stage or even the atmosphere. Only a small amount of bleed air is needed to establish the required pressure difference, which greatly reduces the bleed air flow to the engine's main flow path and reduces efficiency loss. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0020] Figure 1 This is a cross-sectional view of the bearing cavity sealing and induced air pressure boosting structure provided by the present invention.

[0021] Figure 2 This is a three-dimensional structural diagram of the sealing bushing and compression blade in this invention.

[0022] Explanation of reference numerals in the attached drawings: 1. Casing; 1a. First cylinder; 1b. First radial ring; 1c. Second cylinder; 1d. Second radial ring; 1e. Third cylinder; 2. Sealing bushing; 2a. Radial section; 2b. First cylinder section; 2c. Second cylinder section; 3. First-stage rectifier blade; 4. First-stage rotor blade; 5. Second-stage rectifier blade; 6. Second-stage rotor blade; 7. Centrifugal rotor blade; 8. Third-stage rectifier blade; 9. Sealing device. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that the terms "first," "second," etc., used in the specification and claims of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein.

[0025] Furthermore, in the technical solution of the present invention, "axial" refers to the direction parallel to the center line of the engine rotation axis; "radial" refers to the direction perpendicular to the center line of the engine rotation axis; and "circumferential" refers to the direction around the engine rotation axis.

[0026] Example 1 Reference Figure 1 and Figure 2 As shown, according to a specific embodiment of the present invention, a bearing cavity sealing bleed gas self-pressurization structure is provided. This structure is mainly used in the bearing cavity lubricating oil sealing system of aero-engines or gas turbines. Its core function is to significantly increase the static pressure of the sealing gas before entering the sealing device, thereby ensuring a reliable sealing pressure differential can be formed under any operating conditions.

[0027] I. Overall Structure and Assembly Relationship The bearing cavity sealing induced air intake self-pressurization structure mainly includes a casing 1, a sealing bushing 2, and a compression blade assembly composed of multi-stage blades. The casing 1 is the fixed part of the engine and has a stepped cylindrical structure. The sealing bushing 2 (also called the sealing runway) is located in the central hole of the casing 1, and the two are arranged coaxially, forming an annular airflow channel between them. The sealing bushing 2 itself is also a stepped cylindrical structure to match the airflow direction and the installation position of different blades.

[0028] Specifically, along the direction of airflow in the sealed venting ( Figure 1 From left to right, the sealing bushing 2 includes a first cylindrical section 2b, a radial section 2a, and a second cylindrical section 2c. The first cylindrical section 2b is located upstream and is the installation location of the axial flow compression unit; the radial section 2a extends outward radially to form an annular platform approximately perpendicular to the axis, used to install the centrifugal rotor blades 7; the second cylindrical section 2c extends downstream and is used to install the sealing device 9.

[0029] Correspondingly, the casing 1 is also constructed as a stepped cylindrical structure to match the shape of the sealing bushing 2, forming a complex yet smooth airflow channel. Along the air intake direction, the casing 1 sequentially includes a first cylindrical body 1a, a first radial ring 1b, a second cylindrical body 1c, a second radial ring 1d, and a third cylindrical body 1e. The first cylindrical body 1a is opposite to the first cylindrical section 2b of the sealing bushing 2, forming a first annular channel. The first radial ring 1b is opposite to the front end of the radial section 2a of the sealing bushing 2, guiding the airflow direction. The second cylindrical body 1c is opposite to the rear end of the radial section 2a of the sealing bushing 2 and the front end of the second cylindrical section 2c, forming a second annular channel. The second radial ring 1d and the third cylindrical body 1e further guide the airflow smoothly towards the sealing device 9.

[0030] II. Composition of the compression blade assembly The compression blade assembly is disposed within the annular airflow channel between the casing 1 and the sealing bushing 2. In this embodiment, the compression blade assembly includes a two-stage axial flow compression unit and a one-stage centrifugal compression unit.

[0031] (a) First-stage axial flow compression unit It consists of a first-stage rectifier blade 3 and a first-stage rotor blade 4.

[0032] First-stage rectifier blade 3: Installed on the inner wall of the first cylinder 1a of the casing 1. Its blade has a certain angle (relative to the axial direction). The function of this blade is to guide the incoming flow (sealing bleed air) into the next stage rotor blade at a predetermined angle of attack, thereby reducing flow losses.

[0033] The first-stage rotor blade 4 is mounted on the outer wall of the first cylindrical section 2b of the sealing bushing 2, and is located downstream of the first-stage rectifier blade 3. When the engine shaft rotates, the sealing bushing 2 drives the first-stage rotor blade 4 to rotate at high speed. The rotating first-stage rotor blade 4 cuts and performs work on the passing airflow, transferring mechanical energy to the gas and causing the total pressure of the gas to increase for the first time.

[0034] (ii) Second-stage axial flow compression unit It consists of a second-stage rectifier blade 5 and a second-stage rotor blade 6.

[0035] The second-stage rectifier blade 5 is also installed on the inner wall of the first cylinder 1a of the casing 1, located downstream of the first-stage rotor blade 4. It has two functions: first, as a diffuser, it converts the dynamic pressure portion of the high-speed airflow at the outlet of the first-stage rotor blade 4 into static pressure; second, it readjusts the direction angle of the airflow so that it enters the second-stage rotor blade 6 at a suitable angle.

[0036] The second-stage rotor blade 6 is mounted on the outer wall of the first cylindrical section 2b of the sealing bushing 2, downstream of the second-stage rectifier blade 5. It further performs work on the gas through rotation, resulting in a second significant increase in the total gas pressure.

[0037] (III) Centrifugal Compression Unit It consists of centrifugal rotor blades 7. These centrifugal rotor blades 7 are mounted on the radial section 2a of the sealing bushing 2. Due to the stepped design of the casing 1 and the sealing bushing 2, after two stages of axial flow compression, the airflow is guided by the first radial ring 1b and the radial section 2a, smoothly changing from axial flow to radial outward flow. The high-speed rotating centrifugal rotor blades 7 utilize powerful centrifugal force to compress the gas. The gas is accelerated and thrown to the outer edge in the flow channel of the centrifugal blades, resulting in a sharp increase in pressure and density. This is the stage with the most significant pressure rise in the entire pressurization process.

[0038] (iv) Final diffusion and stagnation structure In this embodiment, the compression blade assembly also includes a third-stage rectifier blade 8. This third-stage rectifier blade 8 is mounted on the inner wall of the second cylinder 1c of the casing 1, located at the radially outer end of the centrifugal rotor blade 7. The third-stage rectifier blade 8 has a rectangular blade shape and is parallel to the axial direction of the casing 1. The purpose of this special design is to completely halt the high-speed rotating airflow in the circumferential direction. When the high-speed rotating airflow passes through these axially parallel flat blades, its circumferential velocity component is forced to zero, and the absolute velocity direction of the airflow is adjusted to a purely axial direction. This process is equivalent to a powerful diffuser, converting most of the kinetic energy of the airflow into static pressure energy, so that the static pressure of the sealing gas before entering the sealing device reaches its maximum value. This is the key to solving the problem of "insufficient static pressure before sealing" mentioned in the background art.

[0039] III. Sealing device and lubricating oil chamber Following the third-stage rectifier blade 8 is the sealing device 9. (For example...) Figure 1 As shown, the sealing device 9 is fitted onto the second cylindrical section 2c of the sealing bushing 2 and located inside the third cylindrical body 1e of the casing 1. This sealing device 9 is a graphite sealing structure, capable of withstanding high pressure differentials and possessing good self-lubrication and wear resistance. The other side of the sealing device 9 (the side facing away from the airflow) is the lubricating oil chamber that needs to be protected. Graphite sealing structures are conventional existing technology and will not be described in detail here.

[0040] IV. Working Process and Principle The working process of the self-boosting structure of the present invention is described in detail below with reference to the above structure.

[0041] Once the aircraft engine or gas turbine is started and running, the sealing bushing 2 rotates synchronously with the engine main shaft. Bleed air supplied by an external air source enters the annular inlet between the casing 1 and the sealing bushing 2 at relatively low pressure and velocity. The source of the bleed air is very flexible; it can be drawn from fixed locations on fan or compressor components, or directly from the atmospheric environment.

[0042] First, the airflow enters the first annular channel and passes through the first-stage rectifier blades 3, where its angle of attack is adjusted to a suitable angle. Then, the rotating first-stage rotor blades 4 perform the first power compression on the airflow. Both the total pressure and velocity of the airflow are increased.

[0043] The high-speed airflow exiting the first-stage rotor blade 4 immediately enters the second-stage rectifier blade 5. The channel of the second-stage rectifier blade 5 is diffused, acting as a diffuser. Here, the airflow velocity decreases, while the static pressure increases. At the same time, the airflow angle is also readjusted to prepare for entry into the second-stage rotor blade 6.

[0044] Next, the airflow enters the second-stage rotor blades 6. This is the second axial-flow compression. The second-stage rotor blades 6 also do work on the airflow, further increasing the total pressure and velocity of the airflow. Thus, through two stages of axial-flow compression, the gas pressure has been significantly increased compared to the inlet.

[0045] Subsequently, guided by the turning channel formed by the first radial ring 1b of the casing 1 and the radial section 2a of the sealing bushing 2, the airflow turns radially and enters the centrifugal rotor blades 7. The high-speed rotation of the centrifugal rotor blades 7 exerts a strong centrifugal force on the airflow, "throwing" the gas radially outward. During this process, the gas is violently compressed, and its pressure and density increase sharply.

[0046] Finally, the high-speed, high-pressure airflow enters the third-stage rectifier blade 8. Since the third-stage rectifier blade 8 is a rectangular straight blade parallel to the axial direction, it forcibly eliminates the circumferential rotational velocity component of the airflow, achieving complete airflow stagnation. Almost all the kinetic energy of the airflow is converted into static pressure energy. At this point, the static pressure of the sealing gas reaches its highest point in the entire flow path, far exceeding the initial pressure before the first-stage rectifier blade 3. This extremely high static pressure is the key to solving the problem of insufficient sealing bleed pressure in existing technologies.

[0047] This high-pressure sealing gas then flows through the sealing device 9. Since the pressure in the lubricating oil chamber on the other side of the sealing device is relatively low, this high pressure, established by the invention's self-pressurizing structure and far exceeding the lubricating oil chamber pressure, forms a reliable and stable sealing pressure differential. Under this pressure differential, even the presence of minute gaps can effectively prevent lubricating oil from leaking from the lubricating oil chamber to the air chamber side.

[0048] V. Optimization of Structural Parameters To ensure that the aforementioned self-supercharging structure can meet sealing requirements under various extreme operating conditions (especially when the engine is running at idle, at which point the spindle speed is the lowest and the supercharging capacity requirement is the highest), this invention proposes an optimal range for key design parameters.

[0049] 1. Blade Consistency: The number of rectifier blades and rotor blades in each stage of the axial flow compressor unit is determined based on the diameter of the sealing bushing 2. The blade consistency (i.e., the ratio of blade chord length to blade spacing) is between 0.5 and 2. Insufficient consistency leads to insufficient airflow control and low compression efficiency; excessive consistency increases airflow friction and blade weight. A consistency range of 0.5 to 2 ensures good compression performance while balancing structural strength and weight.

[0050] 2. Blade Installation Angle: For axial-flow compressor blades and rotor blades, the angle between the blades and the engine axis is 30° to 60°. This angle range represents a favorable balance between work capacity, flow stability, and structural feasibility. Too small an angle results in blades that are too "flat," leading to high thrust but a tendency to stall; too large an angle results in blades that are too "steep," providing strong distortion tolerance but reducing work capacity. 30° to 60° is a typical design range for axial compressors. Simultaneously, the outlet direction of the centrifugal rotor blade 7 also has an angle of 30° to 60° relative to the radial direction. This angle determines the absolute velocity direction of the gas leaving the centrifugal impeller, directly impacting subsequent diffuser stagnation efficiency.

[0051] 3. Overall Pressure Ratio: The overall pressure ratio of the compression blade assembly at engine idle is not less than 5. This is to ensure that even at the engine's worst operating point—idle (when the rotor speed is lowest and the centrifugal force effect is weakest)—the static pressure before entering the sealing device remains sufficiently high to form an effective sealing pressure differential. This specification ensures that the sealing pressure differential is far greater than the critical value for lubricating oil leakage at any stage of flight, thereby completely solving the problem of insufficient sealing pressure under low-speed conditions mentioned in the background technology.

[0052] This embodiment achieves highly efficient autonomous pressurization of the sealing gas bleed by designing the casing 1 and sealing bushing 2 as a mutually matching stepped structure, and arranging a two-stage axial-flow-one-stage centrifugal combined compression blade between them. In particular, a third-stage rectifier blade 8 with axial parallel direction is set to stagnate the diffusion. Combined with reasonable blade consistency, installation angle, and an idle total pressure ratio of not less than 5, it achieves highly efficient autonomous pressurization of the sealing gas bleed. The static pressure of the sealing gas before entering the sealing device 9 is greatly improved, providing sufficient and stable sealing pressure differential even under extreme conditions such as idle, fundamentally solving the technical problem of insufficient static pressure before sealing in the prior art.

[0053] Example 2 Although the above embodiment 1 describes in detail a specific scheme including a two-stage axial flow compression unit and a one-stage centrifugal compression unit, the present invention is not limited thereto.

[0054] Depending on the engine model, bearing cavity size, and required sealing pressure differential level, the number of stages in the axial-centrifugal combined compressor blade can be freely combined. The compressor blade assembly includes at least one axial-flow compressor unit and one centrifugal compressor unit. This means that for some small gas turbines or applications with less stringent sealing requirements, a single-stage axial-flow compressor unit plus one-stage centrifugal compressor unit can be used. Although the overall pressure ratio may be relatively low (but still needs to meet the requirement of an overall pressure ratio of not less than 5 at idle, which can be achieved by increasing the single-stage load or optimizing the blade design), it is sufficient to meet its specific operating conditions, while also offering a simpler structure and lower cost.

[0055] Conversely, for very large aero engines or special applications requiring sealing under extremely high pressure, an additional axial or centrifugal stage can be added after the two-stage axial flow and one-stage centrifugal stage, forming a multi-stage combination scheme such as a three-stage axial flow and two-stage centrifugal stage. These variant schemes all remain true to the core concept of this invention: utilizing axial and centrifugal blades in series to autonomously pressurize the sealing bleed air by rotating the rotor itself.

[0056] Example 3 In this embodiment, the other structures are basically the same as in Embodiment 1, except for the selection of the type of sealing device 9.

[0057] Although a graphite sealing structure was selected in Example 1, other forms of sealing device 9 can be used in practical applications. For example, a grate seal can be used: it has a simple structure, is resistant to high temperatures, and is reliable in operation, suitable for situations with large pressure differentials but where leakage requirements are not extremely stringent. Alternatively, a brush seal can be used: its leakage rate is much lower than that of a grate seal, it has good flexibility, adapts to the transient radial runout of the rotor, and has extremely high sealing efficiency.

[0058] Regardless of the specific sealing structure chosen, as long as it is installed downstream of the compression blade assembly of the present invention and relies on the pressurized gas provided by the present invention for sealing, and satisfies the assembly relationship of "the sealing device is sleeved on the second cylindrical section of the sealing bushing and located in the third cylindrical body of the casing", it should fall within the protection scope of the present invention.

[0059] As can be seen from the detailed description of the above embodiments, the bearing cavity sealing and induced gas self-pressurization structure provided by the present invention has made significant progress compared with the prior art, especially providing a perfect solution to the technical problem of "insufficient static pressure of sealing gas before entering the sealing device".

[0060] Significantly increased static pressure before sealing: Through multi-stage compression using a combination of axial and centrifugal flow, especially the stagnant diffusion of the last stage's axial parallel rectifier blades, the static pressure before the sealing device reaches several times the inlet pressure (≥5 at idle). This is the core technical effect of the invention, directly solving the problem of establishing a sealing pressure differential in existing technologies and ensuring zero oil leakage.

[0061] System architecture innovation: It completely abandons the complex bleed air conversion device in the traditional design, simplifies the engine's external pipelines and accessories, and eliminates the risk of bleed air conversion function failure.

[0062] Improved energy efficiency: Only a very small amount of gas needs to be drawn from a fixed low-pressure stage or the atmosphere, and the energy comes from shaft work, so the impact on the thermal efficiency of the main cycle is negligible. At the same time, the amount of bleed air is reduced, which improves the overall fuel economy of the engine.

[0063] Strong adaptability to operating conditions: The boosting capacity changes automatically with the speed. It can still ensure a sufficient boost ratio at slow speeds and has a greater margin at high speeds, without the need for active control.

[0064] In summary, the technical solution provided by this invention is a major innovation in the field of aero-engine lubricating oil sealing, with extremely high industrial application value and commercial prospects.

[0065] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A bearing cavity sealing and bleed air self-pressurization structure, characterized in that, include: Casing (1); Sealing bushing (2), the sealing bushing (2) is disposed in the central hole of the casing (1), and the two are coaxially arranged to form an annular airflow channel; the sealing bushing (2) is a stepped cylindrical structure; And a set of compression blades disposed within the annular airflow channel; The compression blade assembly includes at least one axial flow compression unit and one centrifugal compression unit; Each stage of the axial flow compression unit includes rectifier blades and rotor blades arranged sequentially along the axial direction. The rectifier blades are mounted on the casing (1), and the rotor blades are mounted on the sealing bushing (2). The centrifugal compression unit includes centrifugal rotor blades (7), which are mounted on the radial section (2a) of the sealing bushing (2). A sealing device (9) is provided downstream of the airflow outlet of the compression blade assembly, and the other side of the sealing device (9) is a lubricating oil chamber; The sealing bushing (2) rotates with the engine shaft, which drives the rotor blades and centrifugal rotor blades (7) to rotate, thereby compressing and diffuses the sealing bleed air.

2. The bearing cavity sealing and induced air pressure boosting structure according to claim 1, characterized in that, The compression blade assembly includes a two-stage axial flow compression unit and a one-stage centrifugal compression unit.

3. The bearing cavity sealing and induced air pressure boosting structure according to claim 1 or 2, characterized in that, The number of rectifier blades and rotor blades in each stage of the axial flow compression unit is determined according to the diameter of the sealing bushing (2), and the blade consistency is 0.5 to 2.

4. The bearing cavity sealing and induced air purging self-pressurization structure according to claim 1 or 2, characterized in that, The included angle between the rectifier blade and the rotor blade and the axial direction is 30° to 60°. The exit direction of the centrifugal rotor blade (7) has an angle of 30° to 60° relative to the radial direction.

5. The bearing cavity sealing and induced air pressure boosting structure according to claim 1, characterized in that, The sealed air intake comes from the fixed position of the fan, the fixed position of the compressor component, or the atmospheric environment.

6. The bearing cavity sealing and induced air pressure boosting structure according to claim 1, characterized in that, The total boost ratio of the compression blade assembly is not less than 5 when the engine is running at idle.

7. The bearing cavity sealing and induced air pressure boosting structure according to claim 2, characterized in that, Along the air intake direction, the sealing bushing (2) sequentially includes a first cylindrical section (2b), a radial section (2a), and a second cylindrical section (2c). The casing (1) is also a stepped cylindrical structure, which includes a first cylindrical body (1a), a first radial ring (1b), a second cylindrical body (1c), a second radial ring (1d), and a third cylindrical body (1e) in sequence along the air intake direction. The two-stage axial flow compression unit includes a first-stage rectifier blade (3) and a first-stage rotor blade (4); as well as a second-stage rectifier blade (5) and a second-stage rotor blade (6); The first-stage rectifier blade (3) and the second-stage rectifier blade (5) are both installed on the inner wall of the first cylinder (1a) of the casing (1); The first stage rotor blade (4) and the second stage rotor blade (6) are both installed on the outer wall of the first cylindrical section (2b) of the sealing bushing (2).

8. The bearing cavity sealing and induced air pressurization structure according to claim 7, characterized in that, The compression blade assembly also includes a third-stage rectifier blade (8), which is installed on the inner wall of the second cylinder (1c) of the casing (1). The blade of the third-stage rectifier blade (8) is rectangular, and the third-stage rectifier blade (8) is parallel to the axial direction of the casing (1) to stop the sealing air in the circumferential direction.

9. The bearing cavity sealing and induced air pressure boosting structure according to claim 7, characterized in that, The sealing device (9) is a graphite sealing structure; the sealing device (9) is sleeved on the second cylindrical section (2c) of the sealing bushing (2) and located inside the third cylindrical body (1c) of the casing (1).

10. An aircraft engine or gas turbine, characterized in that, Includes the bearing cavity sealing and induced air pressure boosting structure as described in any one of claims 1 to 9.

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