Multistage winding core high-pressure brush seal device and design method thereof

Abstract

The application 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, which comprises a front baffle, a rear baffle and a sealing assembly, the sealing assembly is clamped between the front baffle and the rear baffle, the sealing assembly comprises brush filaments and at least two core wires, the outer wall of each core wire is sleeved with a U-shaped flow shielding spring plate, the outer wall of the flow shielding spring plate on the single or multiple core wires in the middle position of the brush filaments is wound to form a multi-stage brush type sealing structure. The multi-stage brush filaments are clamped by the front baffle and the rear baffle through the installation mode of winding the core wires by the brush filaments, a brush type sealing assembly is formed, different winding installation modes can be customized according to different application scenes, the pressure bearing capacity and the service life are improved, in addition, the outer wall of each core wire is sleeved with a U-shaped flow shielding spring plate, the brush filaments can be compressed in the axial direction through the self-elastic force of the flow shielding spring plate, the brush filament expansion amount is reduced, and the sealing performance is further improved.

Description

TECHNICAL FIELD

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

[0002] With the continuous improvement of the performance of an aero-engine, the sealing performance of a 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 currently become an excellent substitute for the labyrinth seal and is widely applied to turbomachinery such as aero-engines and gas turbines. The use of the advanced brush seal at a key position of the aero-engine instead of the traditional labyrinth seal can reduce the fuel consumption of the aero-engine by 2% and increase the thrust-to-weight ratio by about 2%.

[0003] The traditional brush seal structure mainly comprises 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-core brush seal device, which clamps the brush filament bundle through a C-shaped ring, thereby saving 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 "blow-down effect". However, with the continuous development of the aero-engine towards high parameters, the traditional brush seal is difficult to meet the requirements in terms of pressure-bearing capacity. For example, compared with the single-stage brush seal, the multi-stage brush seal has improved pressure-bearing capacity, but due to the difference in the pressure-bearing capacity of the two stages, the second-stage brush seal is more prone to wear, thereby reducing the service life and being difficult to meet the use requirements. SUMMARY

[0004] The application aims to provide a multi-stage winding-core high-pressure-bearing brush seal device and a design method thereof, which can customize different winding installation modes 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 scheme adopted by the application is as follows:

[0006] A multi-stage winding-core high-pressure-bearing brush seal device comprises:

[0007] A front baffle is fixed to the aero-engine stator assembly and located on the side close to the incoming flow.

[0008] A rear baffle is fixed to the aero-engine stator assembly and located downstream of the front baffle.

[0009] 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.

[0010] Further, the thickness of the flow shielding spring plate is 0.2-0.8 mm.

[0011] 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.

[0012] 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.

[0013] 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.

[0014] Further, the surface of the brush filament is processed with a wavy pattern.

[0015] To achieve the above technical effects, the application further provides a design method of a multi-stage winding core high-pressure-bearing brush sealing device for obtaining the brush sealing device, comprising:

[0016] 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-bearing brush sealing device is constructed;

[0017] The three-dimensional transient fluid-structure coupling analysis model is used to simulate the equivalent flow passage area of the last-stage brush filament bundle when the leakage amount is a preset leakage flow limit value of the brush sealing device;

[0018] According to the preset differential pressure limit value of the last-stage brush filament bundle, the equivalent flow passage area of the last-stage brush filament bundle, the design diameter of the brush filament, and the preset leakage flow limit value, the number of rows of the last-stage brush filament bundle is analyzed and obtained;

[0019] Taking the number of rows of each stage of the brush filament bundle upstream of the last-stage brush filament bundle as an input condition, the three-dimensional transient fluid-structure coupling analysis model is used to analyze the leakage flow and differential pressure value of each stage of the brush filament bundle upstream of the last-stage brush filament bundle under different row combinations under the examination working condition, and the number of rows of each stage of the 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.

[0020] Further, the method comprises the steps of: obtaining the number of rows of the final-stage brush wire bundle by analysis wherein viscosity of the downflow air under the working condition, porosity of the brush wire bundle, preset leakage flow limit value of the brush seal device, preset differential pressure limit value of the final-stage brush wire bundle, design diameter of the brush wire in the brush wire bundle, equivalent flow cross-sectional area obtained by simulation.

[0021] Compared with the prior art, the application has the beneficial effects that:

[0022] The multi-stage brush wire bundle is clamped by the front baffle and the rear baffle to form a brush seal assembly through the installation mode of winding the core wire, the number of stages can be in the range of 2-4, different winding installation modes can be customized according to different application scenarios, and the pressure-bearing capacity and service life are improved; in addition, the U-shaped flow shielding spring plate is sleeved on the outer wall of each core wire, the brush wire bundle is pressed in the axial direction through the self-elastic force of the flow shielding spring plate, so that the expansion amount of the brush wire is reduced, and the sealing performance is further improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 Fig. 1 is a structural schematic view of a multi-stage winding core high-pressure brush seal device in an embodiment;

[0024] Figure 2 Fig. 2 is a schematic view of a winding mode of a brush wire in an embodiment;

[0025] 1, front baffle; 2, stator assembly; 201, mounting boss; 3, rear baffle; 4, brush wire bundle; 5, core wire; 6, flow shielding spring plate; 7, rotor; 8, U-shaped clamping plate; 9, pressing nut; 10, elastic expansion sleeve. DETAILED DESCRIPTION

[0026] The application will be further described in detail below in combination with the embodiments and the drawings. However, it should not be understood that the scope of the above-mentioned subject matter of the application is limited to the following embodiments, and any technology realized based on the content of the application belongs to the scope of the application.

[0027] EMBODIMENT

[0028] Referring to Figure 1 A multi-stage winding core high-pressure brush seal device, comprising:

[0029] The front baffle 1 is fixed on the stator assembly 2 of the aero-engine, and the front baffle 1 is located close to the incoming flow side;

[0030] A rear baffle 3 is fixed to the aero-engine stator assembly 2, and the rear baffle 3 is located downstream of the front baffle 1.

[0031] A sealing assembly is clamped between the front baffle 1 and the rear baffle 3; the sealing assembly includes a brush filament bundle 4 and at least two core wires 5, each of which is externally sleeved with a U-shaped flow-blocking spring 6, and the brush filament bundle 4 is wound on the outer wall of the flow-blocking spring 6 of a single or multiple core wires 5 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 aero-engine rotor 7.

[0032] In this 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, to form a brush sealing 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, the pressure-bearing capacity of which can be increased by 3-5 times, and the number of brush filament rows can also be increased step by step to further improve the pressure-bearing capacity and service life; in addition, each of the core wires 5 is externally sleeved with a U-shaped flow-blocking spring 6, the thickness of the flow-blocking spring 6 ranges from 0.2mm to 0.8mm, and has a certain elasticity, which can press the brush filament bundle 4 in the axial direction through its own elastic force, thereby reducing the expansion amount of the brush filament and further improving the sealing performance.

[0033] 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 winding cores, and the number of brush filaments of a, b and c is controlled in the actual processing process to control the number of brush filament rows of each stage, so that the number of brush filament rows 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.

[0034] The brush filament material in the brush filament bundle 4 in this embodiment can be selected from metal materials or inorganic non-metallic materials, and can also be selected according to the use scenario, 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 brush filament blowdown effect, reduce wear, and thus prolong the service life.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] Based on the same inventive concept, the embodiment also provides a design method of a multi-stage winding core high-pressure-bearing brush seal device, for obtaining the brush seal device, comprising:

[0039] Step one, constructing a three-dimensional transient fluid-structure coupling analysis model of the multi-stage winding core high-pressure-bearing brush seal device according to the geometric structure of the brush seal device;

[0040] 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;

[0041] 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;

[0042] In the embodiment, the row number of the last-stage brush bundle 4 is analyzed and obtained by analyzing to obtain the row number of the last-stage brush bundle 4 wherein is the dynamic viscosity of the downflowing air under the test condition, is the porosity of the brush bundle 4, a preset leakage flow limit value of the brush seal device, a preset differential pressure limit value of the last-stage brush bundle 4, a designed diameter of the brush wire in the brush bundle 4, an equivalent flow cross-sectional area obtained by simulation.

[0043] Step four, taking the number of rows of each-stage brush bundle 4 upstream of the last-stage brush bundle 4 as an input condition, the leakage flow and the differential pressure of the last-stage brush bundle 4 under different row combinations of each-stage brush bundle 4 upstream of the last-stage brush bundle 4 are obtained by analyzing the three-dimensional transient fluid-structure coupling analysis model under the working condition, and the number of rows of each-stage brush bundle 4 is selected, which is that the leakage flow of the last-stage brush bundle 4 is less than or equal to the preset leakage flow limit value and the differential pressure of the last-stage brush bundle 4 is less than or equal to the preset differential pressure limit value of the last-stage brush bundle 4.

[0044] In the embodiment, the equivalent flow cross-sectional area of the last-stage brush bundle 4 when the leakage flow is the preset leakage flow limit value of the brush seal device is obtained by using the three-dimensional transient fluid-structure coupling analysis model of the multi-stage winding core high-pressure-bearing brush seal device, and the number of rows of the last-stage brush bundle 4 is calculated; then the optimal row combination of each-stage brush bundle 4 is obtained by taking the number of rows of the last-stage brush bundle 4, the preset leakage flow limit value, and the preset differential pressure limit value of the last-stage brush bundle 4 as constraint conditions. The optimal row combination can ensure the sealing performance and further ensure that the entire brush seal device has good pressure-bearing capacity under high differential pressure. In addition, the method can 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-bearing brush seal device.

[0045] 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 wound core high-pressure brush sealing device, characterized in that, include: A front baffle, the front baffle being fixed to the stator assembly of the aircraft engine, and the front baffle being located on the side closer to the incoming flow; A rear baffle, which is fixed to the stator assembly of the aircraft engine and is located downstream of the front baffle; A sealing assembly is disposed between the front baffle and the rear baffle; the sealing assembly includes a bristle bundle and at least two core wires, each core wire having a U-shaped baffle sleeve on its outer wall, the bristle bundle being wound around the outer wall of the baffle on one or more core wires to form a multi-stage brush-type sealing structure, the number of bristle rows increasing progressively, and the bristle ends of the sealing assembly contacting and engaging with the outer wall of the aero-engine rotor component; A U-shaped clamp is also provided between the front baffle and the rear baffle, and the core wires are all clamped in the U-shaped clamp.

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

3. The brush sealing device according to claim 1, characterized in that, The stator assembly is provided with a mounting boss that abuts against the rear baffle. The front baffle is adjustablely mounted on the stator assembly by means of a clamping nut to press 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.

4. The brush sealing device according to claim 1, characterized in that, The bristles of the bristle bundle are made of metal or non-metal, and the cross-section of the bristles is elliptical.

5. The brush sealing device according to claim 4, characterized in that, The surface of the brush bristles is processed with a wavy pattern.

6. A design method for a multi-stage wound core high-pressure brush seal device, used to obtain the brush seal device according to any one of claims 1-5, characterized in that, include: Based on the geometric structure of the brush sealing device, a three-dimensional transient fluid-structure interaction analysis model of the multi-stage core-wound high-pressure brush sealing device is constructed. The equivalent flow cross-sectional area of ​​the final-stage brush filament bundle when the leakage rate is the design leakage flow limit value of the brush sealing device is obtained by simulation using the three-dimensional transient fluid-structure interaction analysis model. Based on the design differential pressure limit of the final stage brush filament bundle, the equivalent flow cross-sectional area of ​​the final stage brush filament bundle, the design diameter of the brush filaments, and the design leakage flow limit, the number of rows of the final stage brush filament bundle is analyzed and obtained. ,in To assess the dynamic viscosity of the flowing air under operating conditions, The porosity of the brush filament bundle. This is the design leakage flow limit value for the brush seal device. Design differential pressure limit value for the final stage brush filament bundle. The design diameter of the bristles in the bristle bundle. The equivalent flow cross-sectional area obtained from the simulation; Using the number of rows of brush filaments upstream of the final stage brush filament bundle as input, the leakage flow rate and pressure difference of the final stage brush filament bundle are obtained through the three-dimensional transient fluid-structure interaction analysis model under the test conditions, under different combinations of row numbers. The number of rows of brush filament bundles upstream of the final stage brush filament bundle is selected such that the leakage flow rate of the final stage brush filament bundle is less than or equal to the design leakage flow rate limit and the pressure difference of the final stage brush filament bundle is less than or equal to the design pressure difference limit of the final stage brush filament bundle.

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