Multi-stage winding core high-pressure-bearing brush type sealing device and design method thereof

Abstract

The invention relates to the field of aero-engine design, and discloses a multi-stage winding core high-pressure-bearing brush type sealing device and a design method thereof.The multi-stage winding core high-pressure-bearing brush type sealing device comprises a front baffle, a rear baffle and a sealing assembly, and the sealing assembly is clamped between the front baffle and the rear baffle; the sealing assembly comprises a brush wire bundle and at least two core wires, the outer wall of each core wire is sleeved with a U-shaped flow shielding elastic piece, and the middle of the brush wire bundle is wound around the outer walls of the flow shielding elastic pieces on one or more core wires to form a multi-stage brush type sealing structure. By means of the installation mode that the brush wire bundles wind the core wire, the multiple stages of brush wire bundles are clamped through the front baffle and the rear baffle to form the brush type sealing assembly, different winding installation modes can be customized according to different application scenes, the pressure bearing capacity is improved, and the service life of the brush type sealing assembly is prolonged; in addition, the outer wall of each core wire is sleeved with a U-shaped flow shielding elastic piece, the brush wire bundles can be pressed in the axial direction through the elasticity of the flow shielding elastic pieces, and therefore the swelling amount of the brush wires is reduced, and the sealing performance is further improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aero-engine design, and discloses a multi-stage winding core high-pressure brush seal device and a design method thereof. BACKGROUND

[0002] With the continuous improvement of the performance of aero-engines, the sealing performance of the sealing device as an important component of the aero-engine directly affects the performance of the aero-engine, and excellent dynamic sealing can significantly improve the working efficiency and reliability of the aero-engine. As a new type of contact dynamic sealing, the brush seal has become an excellent substitute for the labyrinth seal and is widely used in turbomachinery such as aero-engines and gas turbines. The use of advanced brush seals in key parts of the engine instead of traditional labyrinth seals can reduce the fuel consumption of the engine by 2% and increase the thrust-to-weight ratio by about 2%.

[0003] The traditional brush seal structure mainly consists of a front baffle, a rear baffle and a brush filament bundle, and the brush filament bundle is clamped and welded by the front and rear baffles to form an assembly. The German MTU company proposes a winding brush seal device, which clamps the brush filament bundle through a C-shaped ring, thereby eliminating the traditional welding process and having a smaller structure space. Some brush seal devices at home and abroad mainly focus on improving the performance and service life of the brush seal device by reducing the "hysteresis effect", "wear performance" and "blowdown effect". However, with the continuous development of aero-engines towards high parameters, the traditional brush seal is difficult to meet the requirements in terms of pressure-bearing capacity. For example, compared with a single-stage brush seal, the pressure-bearing capacity of a multi-stage brush seal is improved, but due to the difference in pressure-bearing capacity between the two stages, the second-stage brush seal is more prone to wear, resulting in reduced service life, and thus it is difficult to meet the use requirements. SUMMARY

[0004] The purpose of the present application is to provide a multi-stage winding core high-pressure brush seal device and a design method thereof, which can customize different winding installation methods according to different application scenarios, improve the pressure-bearing capacity and service life, and reduce the expansion of the brush filaments, thereby further improving the sealing performance.

[0005] In order to achieve the above technical effects, the technical solution adopted by the present application is as follows: A multi-stage winding core high-pressure brush seal device, comprising: a front baffle, the front baffle being fixed to an aero-engine stator assembly, and the front baffle being located on the side close to the incoming flow; a rear baffle, the rear baffle being fixed to the aero-engine stator assembly, and the rear baffle being located downstream of the front baffle; A sealing assembly is clamped between the front baffle and the rear baffle; the sealing assembly comprises a brush filament bundle and at least two core wires, each of the core wires is externally sleeved with a U-shaped flow shielding spring plate, the brush filament bundle is wound on the outer wall of the flow shielding spring plate of a single or multiple core wires at a middle position to form a multi-stage brush sealing structure, and the brush filament end of the sealing assembly is in contact with the outer wall of the rotor component of the aero-engine.

[0006] Further, the thickness of the flow shielding spring plate is 0.2-0.8 mm.

[0007] Further, a U-shaped clamping plate is further arranged between the front baffle and the rear baffle, and the core wires are clamped in the U-shaped clamping plate.

[0008] Further, an installation boss abutting against the rear baffle is arranged on the stator assembly, the front baffle is adjustably installed on the stator assembly through a compression nut to compress the sealing assembly between the front baffle and the rear baffle, and an elastic expansion sleeve is arranged between the front baffle and the rear baffle.

[0009] Further, the brush filament material of the brush filament bundle is metal or inorganic non-metal, and the cross section of the brush filament is an elliptical structure.

[0010] Further, the surface of the brush filament is processed with a wavy pattern.

[0011] To achieve the above technical effects, the application further provides a design method of a multi-stage winding core high-pressure brush sealing device for obtaining the brush sealing device, comprising: According to the geometric structure of the brush sealing device, a three-dimensional transient fluid-structure coupling analysis model of the multi-stage winding core high-pressure brush sealing device is constructed; The equivalent flow passage cross-sectional area of the last-stage brush filament bundle is simulated and obtained by using the three-dimensional transient fluid-structure coupling analysis model when the leakage amount is the preset leakage flow limit value of the brush sealing device; According to the preset differential pressure limit value of the last-stage brush filament bundle, the equivalent flow passage cross-sectional area of the last-stage brush filament bundle, the brush filament design diameter and the preset leakage flow limit value, the number of rows of the last-stage brush filament bundle is analyzed and obtained; Under the examination working condition, the leakage flow and the differential pressure value of each stage brush filament bundle upstream of the last-stage brush filament bundle under different row combinations are analyzed and obtained by using the three-dimensional transient fluid-structure coupling analysis model, and the row number of each stage brush filament bundle is selected, which satisfies the conditions that the leakage flow of the last-stage brush filament bundle is less than or equal to the preset leakage flow limit value and the differential pressure of the last-stage brush filament bundle is less than or equal to the preset differential pressure limit value of the last-stage brush filament bundle.

[0012] Further, the three-dimensional transient fluid-structure coupling analysis model is constructed by using The number of rows of the last-stage brush filament bundle is analyzed and obtained wherein is the dynamic viscosity of the incoming air under the working condition, is the porosity of the brush bundle, is the preset leakage flow limit value of the brush seal device, is the preset differential pressure limit value of the last-stage brush bundle, is the designed diameter of the brush wire in the brush bundle, is the equivalent flow cross-sectional area obtained by simulation.

[0013] Compared with the prior art, the present application has the beneficial effects that: The present application uses the installation mode of winding the core wire with the brush bundle, clamps the multi-stage brush bundle with the front baffle and the rear baffle to form a brush seal assembly, the number of stages of which can be in the range of 2-4, and different winding installation modes can be customized according to different application scenarios to improve the pressure-bearing capacity and service life. In addition, a U-shaped flow shielding spring plate is sleeved on the outer wall of each core wire, and the brush bundle can be pressed in the axial direction by the self-elastic force of the flow shielding spring plate, thereby reducing the expansion amount of the brush wire and further improving the sealing performance. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a structure schematic view of a multi-stage winding core high-pressure brush seal device in the embodiment; Figure 2 is a winding mode schematic view of a brush wire in the embodiment; 1, front baffle; 2, stator assembly; 201, mounting boss; 3, rear baffle; 4, brush bundle; 5, core wire; 6, flow shielding spring plate; 7, rotor; 8, U-shaped clamping plate; 9, compression nut; 10, elastic expansion sleeve. DETAILED DESCRIPTION

[0015] The present application will be further described in detail below in conjunction with the embodiments and the drawings. However, this should not be understood as limiting the scope of the above-mentioned subject matter of the present application to the following embodiments, and any technology realized based on the content of the present application falls within the scope of the present application.

[0016] EMBODIMENT Referring to Figure 1 A multi-stage winding core high-pressure brush seal device, comprising: A front baffle 1, which is fixed on an aero-engine stator assembly 2 and located on the side close to the incoming flow; A rear baffle 3, which is fixed on the aero-engine stator assembly 2 and located downstream of the front baffle 1; A sealing assembly is clamped between the front baffle 1 and the rear baffle 3; the sealing assembly comprises a brush filament bundle 4 and at least two core wires 5, the outer wall of each core wire 5 is sleeved with a U-shaped flow shielding spring 6, the brush filament bundle 4 is wound on the outer wall of the flow shielding spring 6 of the single or multiple core wires 5 at the middle position to form a multi-stage brush sealing structure, and the brush filament end of the sealing assembly is in contact with the outer wall of the aero-engine rotor 7.

[0017] In the embodiment, the multi-stage brush filament bundle 4 is clamped by the front baffle 1 and the rear baffle 3 through the installation mode of winding the core wire 5 by the brush filament bundle 4, a brush sealing assembly is formed, the number of stages can be in the range of 2-4, different winding installation modes can be customized according to different application scenarios, the pressure bearing capacity can be increased by 3-5 times, the number of brush filament rows can be increased step by step, and the pressure bearing capacity and service life are further improved; in addition, the outer wall of each core wire 5 is sleeved with a U-shaped flow shielding spring 6, the thickness of the flow shielding spring 6 is in the range of 0.2mm-0.8mm, has a certain elasticity, and can press the brush filament bundle 4 in the axial direction through the elastic force, so as to reduce the expansion amount of the brush filament and further improve the sealing performance.

[0018] In specific engineering applications, the number of brush filament rows can also be controlled by changing the winding mode of the brush filament, such as making the number of rows of each stage of brush filament the same. Figure 2 As shown in the figure, in some other embodiments, the brush filament can be wound in the mode of a, or in the direction of b, or in the mode of c across multiple core wires, and in the actual processing process, the number of brush filaments of a, b and c is controlled to control the number of rows of brush filaments of each stage, so that the number of rows of brush filaments of each stage is increased step by step, that is, the sealing performance can be met while higher pressure can be resisted, and the service life can also be prolonged.

[0019] The brush filament material in the brush filament bundle 4 in the embodiment can be selected from metal materials or inorganic non-metallic materials, and can also be selected according to the use scene, or both types of materials can be used, such as the front-stage brush filament bundle 4 which can adopt a metal material with a larger diameter to better resist high-pressure airflow, and the rear-stage brush filament bundle 4 which can adopt a non-metallic polymer material (such as aramid fiber, carbon fiber material, etc.) with a smaller diameter to increase the density of the rear-stage brush filament bundle 4 and better improve the sealing performance. Compared with metal materials, non-metallic materials generally have lighter weight, which can reduce the weight of the entire brush sealing assembly. In addition, the brush filament bundle 4 can select to use brush filaments with an elliptical cross-sectional diameter, which can better improve the pressure bearing capacity, reduce the blowdown effect of the brush filament, reduce wear, and thus prolong the service life.

[0020] In some other embodiments, the sealing performance can be improved by micro-structuring the surface of the brush filaments, for example, when using super-high-temperature-resistant materials (such as high-temperature-resistant ceramic ZTA fibers), the rigidity of the brush filaments can be changed by processing wavy lines on the surface of the brush filaments, thereby improving the flexibility; the temperature and wear resistance of the brush filaments can also be improved by spraying a temperature and wear resistant coating on the surface of the traditional brush filaments.

[0021] In the embodiment, the U-shaped clamping plate 8 is further arranged between the front baffle 1 and the rear baffle 3, and the core wire 5 is clamped in the U-shaped clamping plate 8. The brush bundle 4 is clamped by the clamping plate to form a brush seal assembly. The design of the U-shaped clamping plate 8 not only enhances the fixing effect between the brush bundle 4 and the core wire 5, but also ensures the stability of the brush bundle 4 during installation. Especially when the brush seal assembly is in a high-pressure environment, it can maintain the integrity of its structure and sealing performance.

[0022] In the embodiment, the stator assembly 2 is provided with a mounting boss 201 abutting against the rear baffle 3, and the front baffle 1 is adjustably mounted on the stator assembly 2 by a compression nut 9 to compress the seal assembly between the front baffle 1 and the rear baffle 3. An elastic expansion sleeve 10 is arranged between the front baffle 1 and the rear baffle 3. The elasticity of the elastic expansion sleeve 10 can compensate for certain installation errors, improve the reliability of installation, provide uniform radial pre-tightening force, adapt to small radial displacement during operation, and achieve the effect of vibration reduction, further improving the reliability of sealing.

[0023] Based on the same inventive concept, the embodiment also provides a design method of a multi-stage core-wound high-pressure-bearing brush seal device, for obtaining the brush seal device, comprising: Step one, constructing a three-dimensional transient fluid-structure coupling analysis model of the multi-stage core-wound high-pressure-bearing brush seal device according to the geometric structure of the brush seal device; Step two, simulating to obtain the equivalent flow cross-sectional area of the last-stage brush bundle 4 when the leakage amount is the preset leakage flow limit value of the brush seal device by using the three-dimensional transient fluid-structure coupling analysis model; Step three, analyzing to obtain the row number of the last-stage brush bundle 4 according to the preset differential pressure limit value of the last-stage brush bundle 4, the equivalent flow cross-sectional area of the last-stage brush bundle 4, the design diameter of the brush bundle 4, and the preset leakage flow limit value; In the embodiment, the row number of the last-stage brush bundle 4 is analyzed and obtained by using the following formula: The row number of the last-stage brush bundle 4 is analyzed and obtained by using the following formula: wherein is the dynamic viscosity of the downflowing air under the test condition, is the porosity of the brush bundle 4, is the preset leakage flow limit value of the brush seal device, a differential pressure limit value preset for the last-stage brush filament bundle 4, a designed diameter of the brush filament in the brush filament bundle 4, an equivalent flow cross-sectional area obtained through simulation.

[0024] Step four, taking the number of rows of each stage brush filament bundle 4 upstream of the last-stage brush filament bundle 4 as an input condition, the three-dimensional transient fluid-structure coupling analysis model is used to analyze the leakage flow and differential pressure of the last-stage brush filament bundle 4 under different row combinations of each stage brush filament bundle 4 upstream of the last-stage brush filament bundle 4 under the working condition, and the number of rows of each stage brush filament bundle 4 is selected, which is less than or equal to the preset leakage flow limit value and the differential pressure of the last-stage brush filament bundle 4 is less than or equal to the preset differential pressure limit value of the last-stage brush filament bundle 4.

[0025] In this embodiment, the three-dimensional transient fluid-structure coupling analysis model of the multi-stage winding core high-pressure brush seal device is used to analyze the equivalent flow cross-sectional area of the last-stage brush filament bundle 4 when the leakage is the preset leakage flow limit value of the brush seal device, and the number of rows of the last-stage brush filament bundle 4 is calculated; then the number of rows of the last-stage brush filament bundle 4, the preset leakage flow limit value, and the preset differential pressure limit value of the last-stage brush filament bundle 4 are used as constraint conditions to optimize the optimal row combination of each stage brush filament bundle 4, and the optimal row combination of each stage brush filament bundle 4 is obtained. The optimal row combination can ensure the sealing performance while further ensuring that the entire brush seal device has good pressure-bearing capacity under high differential pressure conditions. In addition, this method can also be flexibly adjusted according to actual needs to meet the sealing requirements under different working conditions, and provides an efficient and reliable solution for the design of the multi-stage winding core high-pressure brush seal device.

[0026] The above is only a preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A multi-stage core-wound high-pressure brush seal device, characterized in that: include: A front baffle, the front baffle being fixed to the aircraft engine stator assembly and being located close to the incoming flow; A rear baffle, the rear baffle being fixed to the aircraft engine stator assembly and located downstream of the front baffle; A sealing assembly is provided between the front baffle and the rear baffle; the sealing assembly comprises a brush bundle and at least two core wires, the outer wall of each core wire is provided with a U-shaped flow-blocking spring sheet, the middle portion of the brush bundle is wound around the outer wall of the flow-blocking spring sheet on a single or multiple core wires to form a multi-stage brush-type sealing structure, and the brush ends of the sealing assembly are in contact with the outer wall of the rotor component of the aircraft engine.

2. The brush seal device according to claim 1, characterized in that The thickness of the flow-blocking spring is 0.2-0.8 mm.

3. The brush seal device according to claim 1, characterized in that A U-shaped clamping plate is further provided between the front baffle and the rear baffle, and the core wires are all clamped in the U-shaped clamping plate.

4. The brush seal device according to claim 3, characterized in that The stator assembly is provided with a mounting boss that abuts against the rear baffle. The front baffle is adjustably mounted on the stator assembly through a clamping nut to compress the sealing assembly between the front baffle and the rear baffle. An elastic expansion sleeve is provided between the front baffle and the rear baffle.

5. The brush seal device according to claim 1, characterized in that The brush filaments of the brush filament bundle are made of metal or inorganic non-metal, and the cross-section of the brush filaments is an elliptical structure.

6. The brush seal device according to claim 5, characterized in that The surface of the brush filament is processed with wavy lines.

7. A design method for a multi-stage winding core high-pressure brush seal device, used to obtain the brush seal device according to any one of claims 1 to 6, characterized in that: include: Based on the geometric structure of the brush seal device, a three-dimensional transient fluid-solid coupling analysis model of a multi-stage core-wound high-pressure brush seal device is constructed; The three-dimensional transient fluid-solid coupling analysis model is used to simulate and obtain the equivalent flow cross-sectional area of ​​the final-stage brush bundle when the leakage amount is a preset leakage flow limit value of the brush seal device; The number of rows of the final-stage brush bundle is obtained by analysis based on the preset pressure difference limit value of the final-stage brush bundle, the equivalent flow cross-sectional area of ​​the final-stage brush bundle, the brush design diameter, and the preset leakage flow limit value; Taking the number of brush bundles at each level upstream of the last-stage brush bundle as the input condition, the leakage flow and pressure difference values ​​of the last-stage brush bundle at each level upstream of the last-stage brush bundle under different row number combinations are obtained through the three-dimensional transient fluid-solid coupling analysis model under the assessment working conditions, and the number of brush bundles at each level whose leakage flow of the last-stage brush bundle is less than or equal to the preset leakage flow limit value and whose pressure difference of the last-stage brush bundle is less than or equal to the preset pressure difference limit value of the last-stage brush bundle is selected.

8. The design method according to claim 7, characterized in that: use Analyze and obtain the number of rows of the final brush bundle ,in In order to evaluate the dynamic viscosity of the downflow air under working conditions, is the porosity of the brush bundle, is the preset leakage flow limit value of the brush seal device, The preset pressure difference limit value for the final brush bundle, is the design diameter of the brush filaments in the brush bundle, is the equivalent flow cross-sectional area obtained by simulation.

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