A brush seal flow-solid-thermal-abrasion multi-physical field efficient coupling method

Abstract

The application discloses a brush seal flow-solid-thermal-abrasion multi-physical field efficient coupling method, and particularly relates to the field of aero-engine sealing. The method comprises the following steps: an entity model of a staggered tube bundle is established, the entity model of the staggered tube bundle is taken as a first model, and a division step is executed; CFD simulation is performed on the first model after grid division, and a flow field distribution is obtained; three-dimensional aerodynamic loads of brush wires are determined based on the flow field distribution; three-dimensional aerodynamic deformation results of the brush wires are determined according to the three-dimensional aerodynamic loads, and the abrasion volume of each brush wire is determined; the entity model of the staggered tube bundle is updated according to the aerodynamic deformation results of the brush wires and the abrasion volume of each brush wire, and a deformation geometry model under aerodynamic force is obtained; the deformation geometry model is taken as the first model, and the division step is executed, until the three-dimensional aerodynamic deformation results of the brush wires reach a first condition, the iteration is stopped, and the accurate simulation of the coupling effect of flow-solid-thermal-abrasion is completed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aero-engine sealing, in particular to a brush seal flow-solid-thermal-abrasion multi-physical field efficient coupling method. BACKGROUND

[0002] With the development of aero-engine / gas turbine towards high thrust-to-weight ratio, high cycle temperature and long service life, the sealing performance of key parts such as high-pressure turbine and inter-stage compressor has become the bottleneck of the overall efficiency and safe service life. Brush seal has become the preferred solution to replace traditional labyrinth seal due to its flexible brush wire self-adaptive deformation and low leakage capacity. However, in the real service environment, the working state of brush seal system is very complex: the deformation of brush wire under the action of high temperature and high pressure aerodynamic load will reconfigure the internal flow passage structure of brush wire bundle in real time, and this geometric change continuously feedbacks to the flow field distribution through the fluid-solid coupling mechanism; at the same time, the heat flow generated by the friction between brush wire and rotor will cause local temperature rise and material softening, and the thermal expansion of rotor aggravates the material wear, which further leads to the change of sealing gap. These flow-solid-thermal-abrasion multi-physical field interaction behaviors form a closed loop feedback, which will continuously affect the sealing performance and service life of brush seal. Since the traditional single physical field analysis method cannot accurately predict the sealing performance degradation trajectory and its internal dynamic behavior, and the traditional strong coupling calculation method has the problems of difficult to converge and long calculation time. SUMMARY

[0003] The main purpose of the present application is to provide a brush seal flow-solid-thermal-abrasion multi-physical field efficient coupling method, which aims to solve the problem that the existing method cannot accurately predict the sealing performance degradation trajectory while ensuring low calculation time.

[0004] To achieve the above object, the application provides a brush seal flow-solid-thermal-abrasion multi-physical field efficient coupling method, comprising: establishing a staggered tube bundle entity model, the staggered tube bundle entity model comprising a baffle, a brush filament bundle and a fluid domain; determining a contact normal pressure of the brush filament and the rotor according to parameters of the staggered tube bundle entity model, taking the contact normal pressure of the brush filament and the rotor as a first contact normal pressure; wherein the parameters comprise an interference amount of the brush filament and the rotor; taking the staggered tube bundle entity model as a first model and performing a division step; the division step comprises: performing mesh division on the first model to obtain a mesh-divided first model; determining a friction heat flux density of a contact bottom surface of the brush filament and the rotor according to the first contact normal pressure, a heat flow distribution coefficient, a friction coefficient, a rotor surface linear velocity and an area of the contact bottom surface; taking the friction heat flux density of the contact bottom surface of the brush filament and the rotor as a boundary condition to perform CFD simulation on the mesh-divided first model to obtain a static pressure; determining a three-dimensional aerodynamic load of the deformed brush filament based on the static pressure, and re-determining the contact normal pressure of the brush filament and the rotor according to the three-dimensional aerodynamic load of the deformed brush filament; determining a three-dimensional aerodynamic deformation result of the brush filament according to an elastic modulus of the brush filament and the three-dimensional aerodynamic load; determining an abrasion volume of each brush filament according to an abrasion coefficient of the brush filament, the re-determined contact normal pressure of the brush filament and the rotor, a rotor surface linear velocity, an abrasion time and a hardness of the brush filament; updating the staggered tube bundle entity model according to the aerodynamic deformation result of the brush filament and the abrasion volume of each brush filament to obtain a deformed geometric model under aerodynamic force; taking the deformed geometric model as the first model and taking the re-determined contact normal pressure of the brush filament and the rotor as the first contact normal pressure, and starting to perform the division step until the three-dimensional aerodynamic deformation result of the brush filament reaches a first condition, stopping iteration and completing the flow-solid-thermal-abrasion coupling.

[0005] Optionally, the mesh division on the first model comprises: dividing a brush filament bundle area into a plurality of sub-domains along a radial direction of the brush filament, performing mesh division on each sub-domain to obtain a mesh model of each sub-domain; and mapping and splicing nodes or elements of adjacent contact surfaces in the mesh models of all the sub-domains one by one to obtain the mesh-divided first model; wherein the brush filament bundle area comprises the fluid domain and a brush filament solid domain.

[0006] Optionally, the determination of the contact normal pressure of the brush filament and the rotor according to the parameters of the staggered tube bundle entity model comprises: determining the contact normal pressure of the brush filament and the rotor according to the interference amount of the brush filament and the rotor, the elastic modulus, the diameter, the length and the installation inclination angle of the brush filament, and a first preset relationship between an aerodynamic force component borne by the brush filament in the radial direction of the rotor and the contact normal pressure.

[0007] Optionally, the frictional heat flux density of the brush filaments and the rotor contact bottom surface is determined according to the first contact normal pressure, the heat flow distribution coefficient, the friction coefficient, the rotor surface linear velocity, and the product of the friction coefficient and the heat flow distribution coefficient, and the quotient of the product and the area of the brush filaments and the rotor contact bottom surface.

[0008] Optionally, the three-dimensional aerodynamic load includes the aerodynamic force components of the brush filaments in the circumferential direction, the axial direction, and the radial direction of the rotor; and the three-dimensional aerodynamic load of the deformed brush filaments is determined based on the static pressure, including: determining the aerodynamic force components of the brush filaments in each direction of the rotor according to the components of the static pressure in the corresponding direction and the length of the brush filaments, to obtain the three-dimensional aerodynamic load of the brush filaments.

[0009] Optionally, the three-dimensional aerodynamic deformation result includes a three-dimensional aerodynamic deformation amount and a deformed position; the three-dimensional aerodynamic deformation result of the brush filaments is determined according to the elastic modulus of the brush filaments and the three-dimensional aerodynamic load; the three-dimensional aerodynamic deformation amount of the brush filaments is determined according to the elastic modulus of the brush filaments, the length of the brush filaments, and the installation inclination angle of the brush filaments, with the three-dimensional aerodynamic load as a boundary condition; and the deformed position of the brush filaments is determined according to the sum of the three-dimensional aerodynamic deformation amount of the brush filaments and the initial position of the brush filaments.

[0010] Optionally, the entity model of the staggered tube bundle is updated according to the aerodynamic deformation result of the brush filaments and the wear volume of each brush filament, to obtain a deformed geometric model under the aerodynamic force, including: generating the solid domains of each row of brush filaments after deformation according to the aerodynamic deformation result of the brush filaments and the wear volume of each brush filament; establishing an envelope body with the deformed brush filaments as a skeleton, and removing the solid domains of the brush filaments and the baffle solid domains by using Boolean operation to obtain a fluid domain after deformation; and updating the entity model of the staggered tube bundle by using the fluid domain after deformation and the solid domains of each row of brush filaments, to obtain the deformed geometric model under the aerodynamic force.

[0011] Optionally, the first condition is that the three-dimensional aerodynamic deformation amount is less than 0.2% of the diameter of the brush filaments.

[0012] Optionally, after the wear volume of each brush filament is determined, the method further includes: determining that the wear of the current brush filament ends when the wear volume of any brush filament reaches a preset volume; and determining that the wear of the brush filament bundle ends when the wear volume of each row of brush filaments in the brush filament bundle reaches the preset volume.

[0013] To achieve the above object, the application also provides a brush seal flow-solid-thermal-abrasion multi-physical field efficient coupling device, comprising: a model establishing module, used for establishing a staggered tube bundle entity model, the staggered tube bundle entity model comprising a baffle, a brush filament bundle and a fluid domain; determining a parameter of a contact normal pressure of the brush filament and the rotor according to the staggered tube bundle entity model, taking the contact normal pressure of the brush filament and the rotor as a first contact normal pressure; wherein the parameter comprises an interference amount of the brush filament and the rotor; a dividing module, used for taking the staggered tube bundle entity model as a first model and performing a dividing step; the dividing step is to perform mesh division on the first model to obtain a mesh-divided first model; a simulation module, used for determining a friction heat flux density of a brush filament and rotor contact bottom surface according to the first contact normal pressure, a friction coefficient, a rotor surface linear velocity and an area of the brush filament and rotor contact bottom surface; taking the friction heat flux density of the brush filament and rotor contact bottom surface as a boundary condition, performing CFD simulation on the mesh-divided first model to obtain a static pressure; an aerodynamic load determining module, used for determining a three-dimensional aerodynamic load of the deformed brush filament based on the static pressure, and re-determining the contact normal pressure of the brush filament and the rotor according to the three-dimensional aerodynamic load of the deformed brush filament; a deformation result determining module, used for determining a three-dimensional aerodynamic deformation result of the brush filament according to an elastic modulus of the brush filament and the three-dimensional aerodynamic load; an abrasion volume determining module, used for determining an abrasion volume of each brush filament according to an abrasion coefficient of the brush filament and the rotor, the re-determined contact normal pressure of the brush filament and the rotor, a rotor surface linear velocity, an abrasion time and a hardness of the brush filament; a model updating module, used for updating the staggered tube bundle entity model according to the aerodynamic deformation result of the brush filament and the abrasion volume of each brush filament to obtain a deformed geometric model under aerodynamic force; and an iteration module, used for taking the deformed geometric model as the first model and taking the re-determined contact normal pressure of the brush filament and the rotor as the first contact normal pressure, starting to perform the dividing step until the three-dimensional aerodynamic deformation result of the brush filament reaches a first condition, stopping iteration and completing flow-solid-thermal-abrasion coupling.

[0014] Compared with the prior art, the application has the following beneficial effects:

[0015] The brush seal flow-solid-thermal-abrasion multi-physical field efficient coupling method of the application realizes flow-thermal two-field coupling solution by establishing a staggered tube bundle entity model, setting a friction heat flux density of a brush filament and rotor contact bottom surface, performing CFD numerical simulation on the staggered tube bundle entity model, determining a three-dimensional aerodynamic load of the brush filament according to flow field distribution, calculating a contact normal pressure of the deformed brush filament and the rotor and a deformation result, determining a deformed geometry of the brush filament under aerodynamic force, and rapidly realizing information mapping and transmission of flow-solid two fields; determining abrasion volumes of each row of brush filaments according to the contact normal pressure of the deformed brush filament and the rotor, updating the staggered tube bundle entity model according to the abrasion volumes and the deformation result, and completing flow-solid-thermal-abrasion two-way data feedback, so as to realize accurate simulation of the flow-solid-thermal-abrasion coupling effect of the brush seal;

[0016] At each CFD simulation, the frictional heat flux density between the brush wire and the rotor is revised by using the heat flux distribution coefficient, the nonlinear correction factor is calculated by the interference amount of the brush wire and the rotor, the length and the angle of the brush wire, the interference amount of the brush wire and the rotor is corrected, and then the contact normal pressure of the brush wire and the rotor is accurately solved; meanwhile, the material hardness is corrected, so as to realize the correction of the wear formula; the real three-dimensional deformation, heat transfer and wear process of the multiple rows of brush wires under the operating condition of the brush seal can be efficiently and accurately reflected, that is, the internal dynamic behavior of the brush seal system, so as to obtain reliable heat flow field information and structure information, and then the accuracy of predicting the seal life is improved;

[0017] Without relying on a complex experimental process, a single-period cross-row tube bundle entity model is established, the sealing performance under different designs and working conditions can be quickly evaluated through multi-physical field coupling numerical simulation, after each iteration is completed, the model is updated, and the CFD simulation calculation is performed by using the updated model, so that the calculation time is reduced, and the model converges quickly. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 FIG. 1 is a flowchart of the flow-solid-thermal-wear multi-physical field efficient coupling method of the brush seal of the present application;

[0019] Figure 2 FIG. 2 is a structural diagram of the cross-row tube bundle entity model in the flow-solid-thermal-wear multi-physical field efficient coupling method of the brush seal of the present application;

[0020] Figure 3 FIG. 3 is a structural diagram of the single-period cross-row tube bundle entity model established in the embodiment of the present application;

[0021] Figure 4 FIG. 4 is a schematic diagram of the grid division in the embodiment of the present application; Figure 3 FIG. 5 is an enlarged view of B in FIG. 4;

[0022] Figure 5 FIG. 6 is a schematic diagram of the grid division in the embodiment of the present application;

[0023] Figure 6 FIG. 7 is an enlarged view of A in FIG. 6; Figure 5 FIG. 8 is an enlarged view of B in FIG. 6;

[0024] Figure 7 FIG. 9 is a deformation result diagram of the brush wire center line in the axial-radial section in the embodiment of the present application;

[0025] Figure 8 FIG. 10 is a schematic diagram of the coupling deformation grid of the brush wire tip in each row in the embodiment of the present application.

[0026] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be clearly and completely described below in combination with the drawings in the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0028] It can be understood that the brush seal system is a high-performance dynamic sealing technology for rotary machines (such as gas turbines, steam turbines, aeroengines and centrifugal compressors), and the core is to realize the low-leakage sealing of gas / liquid medium through the flexible contact between the dense elastic brush filament bundle and the rotor.

[0029] The first embodiment of the present application provides a brush seal flow-solid-thermal-abrasion multi-physical field efficient coupling method, as shown in the figure, specifically comprising the following steps: Figure 1 As shown in the figure, the forked tube bundle entity model includes a baffle, a brush filament bundle 3 and a fluid domain.

[0030] Step S1, establishing a forked tube bundle entity model, as shown in the figure, the forked tube bundle entity model includes a baffle, a brush filament bundle 3 and a fluid domain; Figure 2

[0031] It can be understood that the baffle includes a front baffle 1 and a rear baffle 2, which are respectively located on both sides of the brush filament bundle 3 composed of a plurality of brush filaments 31, and the pressure enters from the front baffle side and is discharged from the rear baffle side. The geometric tolerance during model establishment is kept within 10 -6 m, to ensure the zero error connection of the subsequent mesh and physical field. The three-dimensional aerodynamic load of the brush filament 31 is the aerodynamic force component of the brush filament 31 in the circumferential, axial and radial directions of the rotor 4. Taking the aerodynamic force component of the brush filament 31 in the circumferential direction of the rotor 4 as an example, it is simply referred to as the aerodynamic force component of the brush filament 31 in the circumferential direction below.

[0032] Step S2, determining the contact normal pressure of the brush filament 31 and the rotor 4 according to the parameters of the forked tube bundle entity model, taking the contact normal pressure of the brush filament 31 and the rotor 4 as the first contact normal pressure; wherein the parameters include the interference amount of the brush filament and the rotor;

[0033] Specifically, the parameters further include the elastic modulus, diameter, length and installation angle of the brush filament 31, and the contact normal pressure of the brush filament 31 and the rotor 4 is determined according to the interference amount of the brush filament 31 and the rotor 4, the elastic modulus, diameter, length and installation angle of the brush filament 31, and the aerodynamic force component of the brush filament 31 in the radial direction and the first preset relationship. The first preset relationship is as follows:

[0034] (1);

[0035] In the formula, F ​n is the contact normal pressure of the brush wire 31 and the rotor 4, is the interference amount of the brush wire 31 and the rotor 4, d is the diameter of the brush wire 31, L is the length of the brush wire 31, is the radial aerodynamic force component of the brush wire 31 in the initial state, is 0, is the installation angle of the brush wire 31, E is the elastic modulus of the brush wire 31, I is the moment of inertia;

[0036] In the embodiment, the nonlinear correction factor is The nonlinear correction factor is calculated by the interference amount of the brush wire 31 and the rotor 4, the length and the angle of the brush wire 31, the interference amount of the brush wire 31 and the rotor 4 is corrected, and then the contact normal pressure of the brush wire 31 and the rotor 4 is accurately solved.

[0037] In step S3, the forked tube bundle entity model is taken as a first model, and a division step is performed; the division step is to perform mesh division on the first model;

[0038] Specifically, the brush wire bundle 3 region is divided into a plurality of sub-regions along the radial direction of the brush wire 31, and each sub-region is mesh-divided in a hexahedral structure to obtain a mesh model of each sub-region; the nodes or elements of the adjacent contact surfaces in the mesh models of all sub-regions are one-to-one mapped and spliced through interface or coupling boundaries to obtain the first model after mesh division; wherein the brush wire bundle 3 region includes the brush wire 31 solid domain and the fluid domain between each brush wire 31. In the splicing process, the total number of nodes is compressed to save computing resources under the premise of ensuring accuracy.

[0039] In step S4, the frictional heat flux density of the contact bottom surface of the brush wire 31 and the rotor 4 is determined according to the first contact normal pressure, the heat flow distribution coefficient, the friction coefficient, the surface linear velocity of the rotor 4, and the area of the contact bottom surface of the brush wire 31 and the rotor 4;

[0040] Specifically, the frictional heat flux density of the contact bottom surface of the brush wire 31 and the rotor 4 is determined according to the quotient of the product of the first contact normal pressure, the heat flow distribution coefficient, the friction coefficient, and the surface linear velocity of the rotor 4, and the heat flow distribution coefficient, and the area of the contact bottom surface of the brush wire 31 and the rotor 4 q The calculation formula is as follows:

[0041] (2);

[0042] In the formula, is the heat flow distribution coefficient, which represents the proportion of the friction heat flow into the brush wire 31; Friction coefficient of brush filaments 31 and rotor 4, A Area of contact bottom surface of brush filaments 31 and rotor 4; brush filaments 31 are usually made of Haynes 25 high-temperature alloy, and the rotor 4 surface is usually coated with chromium carbide to inhibit the wear of the rotor shaft. The measured friction coefficient of the two is between 0.23 and 0.35; v Surface linear velocity of rotor 4;

[0043] (3);

[0044] In the formula, Thermal conductivity of brush filaments 31, Thermal conductivity of rotor 4, Density of brush filaments 31, Density of the coating of rotor 4, Constant-pressure specific heat capacity of brush filaments 31, Constant-pressure specific heat capacity of the coating of rotor 4;

[0045] (4);

[0046] In the formula, D Diameter of rotor 4, n Rotational speed of rotor 4;

[0047] (5);

[0048] According to formulas (3)-(5), formula (2) is converted to obtain the final formula of the frictional heat flux density of the contact bottom surface of brush filaments 31 and rotor 4:

[0049] (6);

[0050] Step S5, taking the frictional heat flux density of the contact bottom surface of brush filaments 31 and rotor 4 as a boundary condition, CFD simulation is performed on the first model after grid division to obtain the static pressure;

[0051] Specifically, the boundary conditions are set, including the inlet total pressure, total temperature, and outlet static pressure and total temperature, as well as the frictional heat flux density of the contact bottom surface of brush filaments 31 and rotor 4. According to the inlet total temperature, the physical parameters such as the baffle heat conductivity coefficient and the constant-pressure specific heat capacity at the corresponding temperature are set. Considering the temperature change characteristics of the baffle, CFD simulation is performed on the first model after grid division to obtain the static pressure, specifically the components of the static pressure in the circumferential direction, axial direction and radial direction.

[0052] In the single numerical simulation, when the residuals of the continuity equation, energy equation and turbulence equation are all reduced to 10 -5 and the monitoring quantities (pressure, velocity, flow) remain constant, it is determined that the current flow-heat transfer field coupling calculation converges.

[0053] In this embodiment, the frictional heat flow density between the brush wire 31 and the rotor 4 is revised by using the heat flow distribution coefficient at each CFD simulation, and the contact normal pressure of the brush wire 31 and the rotor 4 is determined by using the interference amount of the brush wire 31 and the rotor 4, so as to correct the wear volume formula, so that the heat transfer and wear process of the multi-row brush wire 31 under the running condition can be simulated and solved efficiently and the real three-dimensional deformation condition is reflected, that is, the internal dynamic behavior of the brush seal system is reflected, and then the wear life of the multi-row brush wire 31 is predicted with high precision.

[0054] Step S6, determining the three-dimensional aerodynamic load of the deformed brush wire 31 based on the static pressure, and re-determining the contact normal pressure of the brush wire 31 and the rotor 4 according to the three-dimensional aerodynamic load of the deformed brush wire 31;

[0055] Specifically, based on the three-dimensional vector analysis method, the aerodynamic force component of the brush wire 31 in each direction is determined according to the component of the static pressure in the corresponding direction and the length of the brush wire 31, and the three-dimensional aerodynamic load of the deformed brush wire 31 is obtained, and the expression is as follows:

[0056] (7);

[0057] In the formula, , , are the aerodynamic force components of the deformed brush wire 31 in the circumferential direction, the axial direction and the radial direction respectively, , , are the components of the static pressure in the circumferential direction, the axial direction and the radial direction respectively, L is the length of the brush wire 31.

[0058] Step S7, determining the three-dimensional aerodynamic deformation result of the brush wire 31 according to the elastic modulus of the brush wire 31 and the three-dimensional aerodynamic load; wherein the three-dimensional aerodynamic deformation result includes the three-dimensional aerodynamic deformation amount and the deformed position;

[0059] Specifically, based on the nonlinear beam bending theory, the three-dimensional aerodynamic load is taken as the boundary condition, the three-dimensional aerodynamic deformation amount of the brush wire 31 is determined according to the elastic modulus, the length of the brush wire 31 and the installation inclination angle of the brush wire 31, and the deformed position of the brush wire 31 is determined according to the sum of the three-dimensional aerodynamic deformation amount of the brush wire 31 and the initial position of the brush wire 31, and the expression is as follows:

[0060] (8);

[0061] In the formula, , , is the deformed position of the brush wire 31, x 0, y 0,z 0 represents the initial position of brush bristles 31. , , These represent the deformation of the brush bristles 31 in the circumferential, axial, and radial directions, respectively. F cx , F cy 、F cz The components of the contact force between brush bristles 31 in the circumferential, axial, and radial directions of the rotor 4 are given. F px , F py 、F pz The components of the contact force between the rear baffle and the brush bristles 31 in the circumferential, axial, and radial directions of the rotor 4 are given. The contact force is determined by the real-time contact state between brush bristles 31 and between brush bristles 31 and the baffle, and is obtained by iterative solution using a line-to-line Hertzian contact model and the theory of elastic foundation beams. The corresponding frictional force can be solved using Coulomb's law of friction. To fit the correction function;

[0062] Step S8: Based on the wear coefficient between the brush bristles 31 and the rotor 4, the redefined contact normal force between the brush bristles 31 and the rotor 4, the surface linear velocity of the rotor 4, the wear time, and the hardness of the brush bristles 31, determine the wear volume of each brush bristle 31; the formula for calculating the wear volume is as follows:

[0063] (9);

[0064] In the formula, K ad The wear coefficients of brush filament 31 and rotor 4 are given. According to experimental results, the wear of brush filament 31 is mainly adhesive wear, and its measured coefficient ranges from 10. -9 -10 -5 between; F n The contact force between the brush bristles 31 and the rotor 4. t i For bristle wear time 31, K fat The fatigue wear coefficient is... for N The fatigue index under cyclic loading; H represents the hardness of brush bristles 31. The calculation needs to consider the influence of the temperature distribution at the tip of brush bristles 31. The expression is:

[0065] (10);

[0066] In the formula, H0 is the material hardness at room temperature. k This is an empirical coefficient representing the change in material hardness with temperature.T 0 is the room temperature value. For example, experimental data for Haynes 25 alloy shows that the specific hardness value ranges from 405 MPa to 722 MPa in the temperature range of 25°C to 760°C.

[0067] In this embodiment, the nonlinear beam bending theory is used to comprehensively consider various forces (including three-dimensional aerodynamic load of the airflow on the brush wire 31, contact force and friction force (fatigue wear coefficient) between the brush wires 31, contact normal pressure and friction force (wear coefficient) between the brush wire 31 and the rotor 4, and contact force and friction force between the brush wire and the back plate) borne by the brush wire, to realize full coupling analysis of the deformation of the brush wire, obtain real-time results of the aerodynamic deformation of the brush wire, and further improve the accuracy of the simulation of the performance degradation of the sealing system.

[0068] In step S9, the deformed geometry model under the aerodynamic force is obtained by updating the interlaced tube bundle entity model according to the aerodynamic deformation results of the brush wire 31 and the wear volume of each brush wire 31.

[0069] Specifically, the solid domain of each row of brush wires 31 after deformation is generated according to the aerodynamic deformation results of the brush wire 31 and the wear volume of each brush wire 31. The brush wire bundle 3 includes multiple rows, and each row is composed of multiple brush wires 31. The solid domain of each row of brush wires 31 after deformation is generated according to the position and wear volume of each row of brush wires 31 after deformation. An envelope is established by taking the brush wire 31 after deformation as a skeleton, and the solid domain of the brush wire 31 and the solid domain of the back plate are removed by using Boolean operation to obtain the fluid domain after deformation. The fluid domain after deformation and the solid domain of each row of brush wires 31 are used to update the fluid domain and the solid domain of the brush wire 31 in the interlaced tube bundle entity model, to obtain the deformed geometry model under the aerodynamic force.

[0070] In step S10, the deformed geometry model is taken as the first model, and the re-determined contact normal pressure between the brush wire 31 and the rotor 4 is taken as the first contact normal pressure, and the division step is started, that is, the mesh of the first model is divided in step S3, until the three-dimensional aerodynamic deformation result of the brush wire 31 reaches the first condition, the iteration is stopped, and the fluid-solid-thermal-wear coupling is completed. The first condition is that the three-dimensional aerodynamic deformation is less than 0.2% of the diameter of the brush wire 31.

[0071] In this embodiment, the single-cycle interlaced tube bundle entity model is established without relying on a complex experimental process, and the sealing performance under different designs and working conditions can be quickly evaluated through multi-physical field coupling numerical simulation. After each iteration is completed, the model is updated, and the CFD simulation calculation is performed by using the updated model, which can reduce the calculation time.

[0072] Further, the coupling method of the application can also track the whole wear process. Specifically, based on the Archard wear theory, whether the wear between the brush filaments 31 and the rotor 4 is ended is determined according to the wear volume of each brush filament 31, so as to realize tracking of the whole wear process. The method for judging whether the wear is ended is that when the wear volume of any brush filament 31 reaches a preset volume, it is determined that the wear of the current brush filament 31 is ended, at this time, the wear termination time of the brush filament 31 is locked as ; when the wear volume of each row of brush filaments 31 in the brush bundle 3 reaches the preset volume, the wear of the brush bundle 3 is ended. This criterion can realize high-precision tracking of the whole wear process through only one scalar comparison. The preset volume is calculated according to the preset interference amount between the brush filaments 31 and the rotor 4.

[0073] The second embodiment of the application provides a brush seal flow-solid-thermal-wear multi-physical field efficient coupling device, comprising:

[0074] The model establishing module is used to establish a staggered tube bundle entity model, the staggered tube bundle entity model comprising a baffle, the brush bundle 3 and a fluid domain; according to parameters of the staggered tube bundle entity model, the contact normal pressure between the brush filaments 31 and the rotor 4 is determined, and the contact normal pressure between the brush filaments 31 and the rotor 4 is taken as a first contact normal pressure; the parameters comprising an interference amount between the brush filaments 31 and the rotor 4;

[0075] The dividing module is used to take the staggered tube bundle entity model as a first model and perform a dividing step; the dividing step is that the first model is mesh-divided to obtain a mesh-divided first model;

[0076] The simulation module is used to determine a frictional heat flux density of a contact bottom surface between the brush filaments 31 and the rotor 4 according to the first contact normal pressure, a heat flow distribution coefficient, a friction coefficient, a surface linear velocity of the rotor 4 and an area of the contact bottom surface between the brush filaments 31 and the rotor 4; the frictional heat flux density of the contact bottom surface between the brush filaments 31 and the rotor 4 is taken as a boundary condition, and the mesh-divided first model is subjected to CFD simulation to obtain a static pressure;

[0077] The aerodynamic load determining module is used to determine a three-dimensional aerodynamic load of the deformed brush filaments 31 based on the static pressure, and to re-determine the contact normal pressure between the brush filaments 31 and the rotor 4 according to the three-dimensional aerodynamic load of the deformed brush filaments 31;

[0078] The deformation result determining module is used to determine a three-dimensional aerodynamic deformation result of the brush filaments 31 according to the elastic modulus of the brush filaments 31 and the three-dimensional aerodynamic load;

[0079] The wear volume determining module is used to determine a wear volume of each brush filament 31 according to a wear coefficient between the brush filaments 31 and the rotor 4, the re-determined contact normal pressure between the brush filaments 31 and the rotor 4, a surface linear velocity of the rotor 4, a wear time and a hardness of the brush filaments 31;

[0080] a model updating module for updating the entity model of the brush tube bundle according to the pneumatic deformation result of the brush wire 31 and the wear volume of each brush wire 31 to obtain a deformation geometry model under the aerodynamic force;

[0081] an iteration module for taking the deformation geometry model as a first model and taking the re-determined contact normal pressure of the brush wire 31 and the rotor 4 as a first contact normal pressure, starting to perform the division step until the three-dimensional pneumatic deformation result of the brush wire 31 reaches a first condition, stopping iteration, and completing the fluid-solid-thermal-abrasive coupling.

[0082] Embodiment

[0083] Step S100, in order to improve the calculation efficiency, a single-row minimum cycle period model is established, as shown in Figures 3-4 , the interference amount of the brush wire 31 and the rotor 4 in the model = 0.1 mm; first, the model is divided into several sub-domains in the radial direction, and the fluid domain and the solid domain are uniformly hexahedronally structured to divide the grid, as shown in Figures 5-6 ; after setting the friction heat flux density of the contact bottom surface of the brush wire 31 and the rotor 4, the CFD numerical simulation is started.

[0084] Step S110, processing the CFD numerical simulation result to obtain the static pressure and extracting the three-dimensional pneumatic load of each brush wire 31; taking the three-dimensional pneumatic load as a boundary condition, calculating the deformation amount of the brush wire 31 and the position of the brush wire 31 after deformation, and the deformation result of the brush wire 31 is as shown in Figure 7 , the axial deformation amount of the tip of the first-row brush wire 31 is 4.8 x 10 -5 m, and the axial deformation amount of the tip of the last-row brush wire 31 is 9.78 x 10 -6 m. It is shown that the multi-field coupling model established in this embodiment can accurately capture the micro-deformation behavior of the brush wire 31 under the combined action of the aerodynamic force, thermal load and contact force, and provide a reliable basis for the sealing gap prediction.

[0085] Step S120, the material of the brush wire 31 in this embodiment is Haynes 25 high-temperature resistant alloy, and the CrMoV steel is selected as the material of the rotor 4. Therefore, the friction coefficient of the brush wire 31 and the rotor 4 is 0.3, the thermal partition index is 0.5; the adhesive wear coefficient Kad is 10 -5 , and the fatigue wear effect is ignored; according to the average temperature of the tip of the brush wire 31, the hardness H is determined as 550 MPa, and the wear volume of the brush wire 31 is calculated.

[0086] Step S130, the distribution of the brush wire 31 before deformation is as shown in Figure 8In the middle (a), the fluid domain and the solid domain of each row of bristles 31 after deformation are used to update the fluid domain and the solid domain of the brush bundle entity model, and a deformed geometric model under aerodynamic force is obtained; the deformed geometric model is taken as the first model to perform the division step, that is, the first model is meshed in step S2 until the three-dimensional aerodynamic deformation result of the bristles 31 reaches the first condition, the iteration is stopped, and the fluid-solid-thermal-abrasive coupling is completed. In the process, the pressure ratio of the inlet and outlet is 3, and the working time is 20 minutes, as shown in Figure 8 In the middle (b), the arrangement mode of the bottom of the bristles 31 is deformed seriously, and then interferes with the main flow direction to form a real feedback of flow-deformation.

[0087] The above is only a preferred embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation using the content of the specification and drawings, or direct or indirect application in other related technical fields, is also included in the patent protection scope of the present application.

Claims

1. A method for efficiently coupling flow, solid, heat and grinding multi-physical fields by brush seal, characterized in that, The method comprises the following steps: establishing a staggered tube bundle entity model, the staggered tube bundle entity model comprising a baffle, a wire bundle and a fluid domain; determining a contact normal pressure of the wire and the rotor according to parameters of the staggered tube bundle entity model, taking the contact normal pressure of the wire and the rotor as a first contact normal pressure; wherein the parameters comprise an interference amount of the wire and the rotor; taking the staggered tube bundle entity model as a first model, performing a division step; the division step comprises meshing the first model to obtain a meshed first model; determining a frictional heat flux density of a contact bottom surface of the wire and the rotor according to the first contact normal pressure, a heat flow distribution coefficient, a friction coefficient, a surface linear velocity of the rotor and an area of the contact bottom surface of the wire and the rotor; taking the frictional heat flux density of the contact bottom surface of the wire and the rotor as a boundary condition, performing a CFD simulation on the meshed first model to obtain a static pressure; determining a three-dimensional aerodynamic load of the deformed wire based on the static pressure, and re-determining the contact normal pressure of the wire and the rotor according to the three-dimensional aerodynamic load of the deformed wire; determining a three-dimensional aerodynamic deformation result of the wire according to an elastic modulus of the wire and the three-dimensional aerodynamic load; determining a wear volume of each wire according to a wear coefficient of the wire and the rotor, the re-determined contact normal pressure of the wire and the rotor, a surface linear velocity of the rotor, a wear time and a hardness of the wire; updating the staggered tube bundle entity model according to the aerodynamic deformation result of the wire and the wear volume of each wire to obtain a deformed geometric model under aerodynamic force; taking the deformed geometric model as the first model and taking the re-determined contact normal pressure of the wire and the rotor as the first contact normal pressure, starting to perform the division step until the three-dimensional aerodynamic deformation result of the wire reaches a first condition, stopping iteration and completing the fluid-solid-thermal-wear coupling.

2. The brush seal flow-solid-thermal-abrasive multi-physical field efficient coupling method according to claim 1, characterized in that, The meshing the first model comprises: dividing a wire bundle area into a plurality of sub-domains along a radial direction of the wire, and meshing each sub-domain to obtain a mesh model of each sub-domain; mapping and splicing nodes or elements of adjacent contact surfaces in the mesh models of all the sub-domains to obtain the meshed first model; wherein the wire bundle area comprises the fluid domain and a wire solid domain.

3. The brush seal flow-solid-thermal-abrasive multi-physical field efficient coupling method according to claim 1, characterized in that, The determining the contact normal pressure of the wire and the rotor according to the parameters of the staggered tube bundle entity model comprises: determining the contact normal pressure of the wire and the rotor according to the interference amount of the wire and the rotor, the elastic modulus of the wire, the diameter of the wire, the length of the wire, the installation inclination angle of the wire, and the product of the aerodynamic force component in the radial direction of the wire, the first preset relationship and the heat flow distribution coefficient.

4. The brush seal flow-solid-thermal-abrasive multi-physical field efficient coupling method according to claim 1, characterized in that, The determining the frictional heat flux density of the contact bottom surface of the wire and the rotor according to the first contact normal pressure, the heat flow distribution coefficient, the friction coefficient, the surface linear velocity of the rotor and the area of the contact bottom surface of the wire and the rotor comprises: determining the frictional heat flux density of the contact bottom surface of the wire and the rotor according to the quotient of the product of the first contact normal pressure, the heat flow distribution coefficient, the friction coefficient, the surface linear velocity of the rotor and the heat flow distribution coefficient, and the area of the contact bottom surface of the wire and the rotor.

5. The brush seal flow-solid-thermal-abrasive multi-physical field efficient coupling method according to claim 1, characterized in that, The three-dimensional aerodynamic load comprises aerodynamic force components of the wire in the circumferential direction, the axial direction and the radial direction. The determining the three-dimensional aerodynamic load of the deformed wire based on the static pressure comprises: Based on the component of static pressure in the corresponding direction and the length of the bristles, the aerodynamic force component of the bristles in each direction is determined, and the three-dimensional aerodynamic load of the bristles is obtained.

6. The brush seal flow-solid-thermal-abrasive multi-physical field efficient coupling method of claim 1, wherein, The three-dimensional aerodynamic deformation result includes the three-dimensional aerodynamic deformation amount and the position after deformation; determining the three-dimensional aerodynamic deformation result of the brush bristles based on the elastic modulus of the bristles and the three-dimensional aerodynamic load includes: Using three-dimensional aerodynamic load as boundary conditions, the three-dimensional aerodynamic deformation of the brush bristles is determined based on the elastic modulus of the bristles, the length of the bristles, and the installation angle of the bristles. The position of the bristles after deformation is determined by the sum of the three-dimensional aerodynamic deformation of the bristles and the initial position of the bristles.

7. The brush seal flow-solid-thermal-abrasive multi-physical field efficient coupling method according to claim 1, characterized in that, The process involves updating the solid model of the cross-branch tube bundle based on the aerodynamic deformation results of the brush bristles and the wear volume of each bristle, resulting in a deformable geometric model under aerodynamic conditions, including: Based on the aerodynamic deformation results of the brush bristles and the wear volume of each brush bristle, the solid domains of each row of deformed brush bristles are generated. An envelope is constructed using the deformed brush bristles as the skeleton, and Boolean operations are used to remove the solid domains of the brush bristles and the baffles to obtain the deformed fluid domain. By utilizing the deformed fluid domain and the solid domain of each row of brush filaments, the solid model of the cross-branch tube bundle is updated to obtain the deformed geometric model under aerodynamic conditions.

8. The brush seal flow-solid-thermal-abrasive multi-physical field efficient coupling method of claim 6, wherein, The first condition is that the three-dimensional aerodynamic deformation is less than 0.2% of the brush filament diameter.

9. The brush seal flow-solid-thermal-abrasive multi-physical field efficient coupling method of claim 1, wherein, After determining the wear volume of each bristle, the method further includes, When the wear volume of any brush bristle reaches the preset volume, the wear of the current brush bristle is determined to have ended; The wear of the brush bundle ends when the wear volume of each row of brush filaments in the bundle reaches the preset volume.

10. A brush seal flow-solid-thermal-abrasive multi-physical field efficient coupling device, characterized in that, include: The model building module is used to build a solid model of the cross-branch tube bundle, which includes baffles, brush bundles, and a fluid domain. Based on the parameters of the cross-branch tube bundle solid model, the contact normal pressure between the brush and the rotor is determined, and the contact normal pressure between the brush and the rotor is taken as the first contact normal pressure. The parameters include the interference between the brush and the rotor. The partitioning module is used to take the cross-shaped tube bundle solid model as the first model and perform a partitioning step; the partitioning step is to perform meshing on the first model to obtain a meshed first model. The simulation module is used to determine the frictional heat flux density between the brush bristles and the rotor contact bottom surface based on the first contact normal pressure, heat flow distribution coefficient, friction coefficient, rotor surface linear velocity, and the area of ​​the brush bristles contacting the rotor bottom surface; and to perform CFD simulation on the first meshed model using the frictional heat flux density between the brush bristles and the rotor contact bottom surface as boundary conditions to obtain the static pressure. The aerodynamic load determination module is used to determine the three-dimensional aerodynamic load of the deformed brush bristles based on the static pressure, and to redetermine the contact normal pressure between the brush bristles and the rotor based on the three-dimensional aerodynamic load of the deformed brush bristles. The deformation result determination module is used to determine the three-dimensional aerodynamic deformation result of the brush bristles based on the elastic modulus and three-dimensional aerodynamic load. The wear volume determination module is used to determine the wear volume of each brush bristle based on the wear coefficient between the brush bristles and the rotor, the redefined contact normal pressure between the brush bristles and the rotor, the linear velocity of the rotor surface, the wear time, and the hardness of the brush bristles. a model updating module, configured to update the entity model of the tube bundle according to the result of the three-dimensional aerodynamic deformation of the brush wire and the wear volume of each brush wire, so as to obtain a deformation geometry model under the aerodynamic force; an iteration module, configured to take the deformation geometry model as a first model, take the re-determined contact normal pressure between the brush wire and the rotor as a first contact normal pressure, start to execute the division step, and stop iteration until the result of the three-dimensional aerodynamic deformation of the brush wire reaches a first condition, so as to complete the fluid-solid-thermal-abrasive coupling.

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