Optimization design method for double-target rotary heat dissipation flow channel structure

Abstract

The invention belongs to the technical field of engineering structure optimization, and particularly relates to a double-target rotary heat dissipation flow channel structure optimization design method which comprises the following steps: converting a three-dimensional model of a rotary structure into a pseudo three-dimensional model structure through a multilayer fluid-solid plane structure to obtain an optimized area plane; performing grid division on the pseudo three-dimensional model, and applying an obtained two-dimensional rotational flow motion rule required by an optimized area plane to the pseudo three-dimensional model in combination with a topological optimization method and a heat conduction effect between a heat source layer and a heat dissipation flow channel layer in the thickness direction; enabling the three-dimensional model to be equivalent to a fluid-solid thermal coupling effect between inner layers of the pseudo three-dimensional structure; carrying out single-target optimization analogue simulation on the optimized structure to obtain upper and lower limit thresholds under single-target optimization, taking the upper and lower limit thresholds as a reference basis for normalization processing of a double-target function, and carrying out weight influence research on the structure; and carrying out structure reconstruction on the optimized pseudo three-dimensional model, and arraying structures with repeated characteristics to obtain a final optimized configuration.

Description

Technical Field

[0001] The invention belongs to the technical field of engineering structure optimization, and in particular relates to a dual-objective rotating heat dissipation channel structure optimization design method. Background Art

[0002] The rotating heat dissipation structure is an efficient heat dissipation design solution that enhances the heat dissipation effect through the movement of rotating parts. The rotating heat dissipation structure usually consists of multiple heat dissipation ribs and two heat dissipation disks arranged opposite to each other. The heat dissipation ribs are distributed between the two disks through a specific structural design. A certain heat dissipation flow channel is reserved between adjacent heat dissipation ribs. The heat dissipation ribs are close to the upper and lower disks, thereby increasing the contact area and improving the heat dissipation efficiency. Compared with the traditional rotating heat dissipation structure, the rotating heat dissipation structure has the advantages of high heat dissipation efficiency, compact structure, and suitability for high-load operation, which can effectively improve the stability and service life of the equipment.

[0003] With the development of my country's advanced equipment manufacturing industry, in order to cope with the higher heat flux density and higher heat load caused by the rapid heating of certain components during operation, the demand for key rotating heat dissipation components in high-end equipment has gradually increased. Modern rotating heat dissipation structure optimization technology should improve the original rotating heat dissipation structure through size optimization and parameter optimization, or propose a new structure based on bionics and other methods to improve the heat exchange performance, but it often depends on the experience of the designer and it is difficult to jump out of the framework of the traditional design structure. For example, the response surface optimization method is used to optimize the heat dissipation ribs of the brake disc, and the structure is optimized by changing the angle, number, thickness and other aspects of the heat dissipation ribs. This method is limited by the initial topology of the heat dissipation rib structure and cannot start from the optimization target itself to distribute the fluid-solid material in the optimal way in the optimization area. The bionic structure is used to determine the heat dissipation rib material according to the designer's experience, such as honeycomb heat dissipation fins. Since this method is often based on the designer's experience, it is difficult to describe its own structural material with a controllable mathematical model while introducing the structure. The quality of its performance is often unpredictable. There is a lack of reliable theoretical support, and it is difficult to obtain the optimal rotating heat dissipation structure, which affects the service life of the rotating heat dissipation structure. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a dual-objective rotating heat dissipation flow channel structure optimization design method, which can enable the rotating heat dissipation structure to achieve the optimal distribution of materials in the fluid-solid mixing area under the consideration of fluid-solid thermal coupling, obtain the overall optimal rotating heat dissipation structure, improve the heat dissipation effect of the rotating heat dissipation structure, and extend its service life.

[0005] The technical solution of the present invention is:

[0006] A dual-objective rotating heat dissipation channel structure optimization design method includes the following steps:

[0007] The geometric model of the rotating heat dissipation structure is simplified, and the simplified three-dimensional model of the rotating heat dissipation structure is converted into a pseudo three-dimensional model structure through a multi-layer fluid-solid plane structure, and the heat source plane and the optimization area plane in the pseudo three-dimensional model structure are obtained, and the initial material of the optimization area plane is defined as a porous medium material between the fluid structure and the solid structure;

[0008] The material parameters of the porous medium material are set according to the topology optimization method, and the thermal conductivity of the porous medium material at the heat dissipation channel in the rotating heat dissipation structure is determined. At the same time, the heat conduction effect between the heat source plane and the optimization area plane along the thickness direction is equivalent to the convection heat transfer coefficient between the heat dissipation channel and the heat source plane, which is applied to the pseudo three-dimensional model structure, so that the simplified three-dimensional model of the rotating heat dissipation structure is equivalent to the fluid-solid thermal coupling effect between the inner layers of the pseudo three-dimensional model structure, and the movement of the porous medium material is controlled by introducing the effect of additional volume force in the porous medium material;

[0009] The established pseudo three-dimensional model structure is meshed and processed to discretize the pseudo three-dimensional model structure into small units, so as to realize single-objective optimization simulation of the pseudo three-dimensional model structure, determine the material volume factor value of the porous medium material, and obtain the upper and lower thresholds under two single-objective optimizations through single-objective optimization simulations, which serve as a reference for the normalization of the dual-objective function, and construct a topology optimization mathematical model. The dual-objective function in the topology optimization mathematical model is used to study the pseudo three-dimensional model structure under the influence of different weight ratios, obtain multiple optimized optimization area planes, and compare the comprehensive performance parameters of the multiple optimized optimization area planes, so as to obtain the optimization area plane with the best comprehensive performance among the multiple optimized optimization area planes as the two-dimensional flow channel plane structure;

[0010] The optimized pseudo three-dimensional model is structurally reconstructed, that is, the obtained two-dimensional flow channel plane structure is three-dimensionally stretched, and the obtained two-dimensional flow channel plane structure is used as the source object to array the structure with repeated features to obtain the final optimized configuration as the preferred rotating heat dissipation structure.

[0011] Preferably, the heat source plane in the pseudo three-dimensional model structure is equivalent to the outer wall of the disk located on the upper and lower sides of the heat dissipation channel in the rotating heat dissipation structure, and the fan-shaped cross-section relative to the upper and lower heat source planes is taken as the heat source input layer in the pseudo three-dimensional model structure, which is equivalent to replacing the heat source input area of ​​the three-dimensional model of the rotating heat dissipation structure.

[0012] Preferably, the method for obtaining the optimized area plane in the pseudo three-dimensional model structure is:

[0013] The fan-shaped cross-section of the heat dissipation channel in the simplified rotating heat dissipation structure in the thickness direction and at the same height as the upper and lower disk surfaces is used as the optimization area plane. The optimization area plane is between the upper and lower heat source planes, and the heat source plane is parallel to the optimization area plane, and the optimization area plane and the upper and lower heat source planes are required to have repeated features in the circumferential direction.

[0014] Preferably, the following formula is used to determine the thermal conductivity of the porous medium material at the heat dissipation channel in the rotating heat dissipation structure and the convection heat transfer coefficient between the heat dissipation channel and the heat source plane through the interpolation function in the topology optimization method:

[0015]

[0016] Where: k(γ) is the thermal conductivity interpolation function of the porous medium material at the heat dissipation channel, h(γ) is the convective heat transfer coefficient interpolation function between the heat dissipation channel and the heat source plane, γ is the material volume factor, and its value varies between 0 and 1. When γ tends to 0, the material is solid, and when γ tends to 1, the material is fluid. f is the thermal conductivity of the fluid material, k s is the thermal conductivity of the solid material, H is the distance between layers in the thickness direction, and h f is the convective heat transfer coefficient of the fluid at the structure, and C1 and C2 are the coefficients of the interpolation function.

[0017] Preferably, the material volume factor γ is determined by the following formula according to the single-objective optimization simulation, and the value of the pseudo three-dimensional model structure is discretized into small units:

[0018]

[0019] in,

[0020]

[0021]

[0022] ρ is the fluid density, T is the stress tensor, -2ρ(ω×v) is the Coriolis force term, -ρω×(ω×r) is the centrifugal force term, ρf is the volume force acting on each unit volume of the fluid, and f r (γ) is the additional volume force used to simulate porous media materials in topology optimization; is the reverse osmosis rate, v abs is the absolute speed in the stationary coordinate system established with the rotation center of the rotating heat dissipation structure as the origin, v abs =v+ω×r, v is the linear velocity of the relative coordinates in the rotating coordinate system around the origin, ω is the angular velocity of the relative coordinates in the rotating coordinate system around the origin, and r is the rotation radius of the relative coordinates in the rotating coordinate system around the origin; α max , αmin When γ takes values ​​between 0 and 1, The maximum and minimum values ​​of min =0, γ is the material volume factor, q is the penalty factor, μ is the fluid dynamic viscosity, Da is the Darcy value, and its value is less than 10 -5 , L is the characteristic length of the heat dissipation channel.

[0023] Preferably, a dual-objective optimization objective function is established by a topology optimization method according to the following formula, the pseudo three-dimensional model structure is studied under the influence of different weight ratios, and the optimized area plane with the best comprehensive performance is determined.

[0024] minobj:J=ω1φ1+ω2φ2

[0025]

[0026] in,

[0027]

[0028]

[0029] ω1 is the weight of the turbulent dissipation energy objective function, ω2 is the weight of the thermal resistance temperature difference objective function, T1 is the surface temperature of the heat source plane, T2 is the temperature of the heat dissipation channel area, μ is the dynamic viscosity, μ T is the turbulent viscosity, v abs is the absolute velocity in the stationary coordinate system, v is the relative velocity in the rotating coordinate system, and v abs =v+ω×r, ω is the angular velocity of the rotating coordinate system, -2ρ(ω×v) is the Coriolis force term, -ρω×(ω×r) is the centrifugal force term, T is the stress tensor, z1 is the thickness of the heat dissipation channel plane, z2 is the thickness of the heat source part, ρf is the volume force per unit volume acting on the fluid material, f r (γ) is the additional volume force used to simulate porous media materials in topology optimization, k(γ) is the thermal conductivity of the material with respect to the change of volume factor, q flux is the heat flux density, h(γ) is the heat transfer coefficient affected by the material volume factor, C p is the specific heat capacity at constant pressure, γ min is the minimum value of the material volume factor, γ max is the maximum value of the material volume factor, which is used to control the proportion of solid and fluid materials in the flow channel, γ avg is the mean value of the material volume factor, φ f is the objective function of turbulent energy dissipation, φ th is the thermal resistance objective function, φ f,min ,φ f,max are the minimum and maximum values ​​of the turbulence dissipation energy objective function, respectively, th,min,φ th,min are the minimum and maximum values ​​of the thermal resistance objective function, T in is the flow channel inlet temperature, A is the heat source surface area, k s is the thermal conductivity of the solid material.

[0030] Preferably, the area in the plane of the optimized region where the material volume factor γ value is less than 0.5 is solid material, and the area where the γ value is greater than 0.5 is fluid material.

[0031] Compared with the prior art, the dual-objective rotating heat dissipation channel structure optimization design method of the present invention has the following beneficial effects:

[0032] 1. This method converts the three-dimensional model of the rotating heat dissipation structure into a pseudo three-dimensional model structure through a multi-layer fluid-solid plane structure to obtain the optimized area plane of the heat dissipation ribs in the rotating heat dissipation structure, and then uses the topological optimization method to enable the rotating heat dissipation structure to achieve the optimal distribution of materials in the fluid-solid mixing area under the consideration of fluid-solid thermal coupling. According to the material distribution results, the entire rotating heat dissipation structure model is reconstructed in the optimized area. It has reliable theoretical support, so that the heat dissipation rib structure material is described by a controllable mathematical model, which can better control the pros and cons of the heat dissipation rib performance and obtain heat dissipation rib materials that better meet the heat dissipation requirements.

[0033] 2. This method introduces the topology optimization method into the NS equation, provides a reliable mathematical model, integrates all the units to be optimized in the overall rotating heat dissipation structure, and comprehensively considers the optimization performance of the overall structure, so that the optimization result no longer depends on the designer's experience. It can start with the optimization goal and reasonably control the optimized structure through optimization parameters, providing designers with a clear optimization direction.

[0034] 3. This method reduces the turbulent dissipation energy of the cooling fluid in the rotating heat dissipation channel while retaining the original structural material usage by imposing material volume factor constraints, and increases the mass flow rate of the cooling fluid in the channel, so that more heat can be taken away per unit time. It also reduces the thermal resistance between the rotating heat dissipation structure and the heat source, which is the objective function, and uses thermal conductivity interpolation to achieve the distribution of fluid-solid materials in the optimized area, thereby improving the heat dissipation performance of the new configuration and extending the service life of the rotating parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a flow chart of a dual-objective rotating heat dissipation channel structure optimization design method according to an embodiment of the present invention;

[0036] Figure 2 Schematic diagram of a pseudo three-dimensional fluid-solid thermal coupling model of a train ventilated brake disc in an embodiment of the present invention;

[0037] Figure 3 It is a schematic diagram of the heat dissipation flow channel result of the pseudo three-dimensional structure of the train ventilation brake disc topology optimization in an embodiment of the present invention;

[0038] Figure 4 It is a schematic diagram of the reconstruction model of the train ventilated brake disc in an embodiment of the present invention.

[0039] Description of reference numerals: 1. heat dissipation rib; 2. brake disc surface; 3. heat source plane; 4. optimization area plane; DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0041] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0042] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0043] See also Figure 1 As shown, in order to achieve ..., this embodiment provides a dual-objective rotating heat dissipation channel structure optimization design method, including the following steps:

[0044] A single heat dissipation channel and the disk surfaces on the upper and lower sides thereof are defined as the rotating heat dissipation structure under study, and the geometric model of the rotating heat dissipation structure is simplified, that is, the three-dimensional model of the rotating heat dissipation structure is converted into a pseudo three-dimensional model structure through a multi-layer fluid-solid plane structure (the fluid-solid plane structure is a two-dimensional plane structure between the fluid structure and the solid structure), and the pseudo three-dimensional model structure includes a heat source plane and an optimization area plane, wherein the heat source plane is equivalent to the outer wall of the disk surface located on the upper and lower sides of the heat dissipation channel in the rotating heat dissipation structure, and the fan-shaped cross section of the heat dissipation channel in the simplified rotating heat dissipation structure in the thickness direction and at the same height as the upper and lower disk surfaces is used as the optimization area plane, and the initial material of the optimization area plane is defined as a porous medium material between the fluid structure and the solid structure, and the heat source plane is assumed to be parallel to the optimization area plane;

[0045] According to the topology optimization method (topology optimization method is a mathematical method for optimizing material distribution in a given area according to given load conditions, constraints and performance indicators, and is a type of structural optimization), the material parameters of the porous medium material are set to determine the thermal conductivity of the porous medium material at the heat dissipation channel in the rotating heat dissipation structure. At the same time, the heat conduction effect between the heat source plane and the optimized area plane along the thickness direction is equivalent to the convection heat transfer coefficient between the heat dissipation channel and the heat source plane, which is applied to the pseudo three-dimensional model structure, so that the simplified three-dimensional model of the rotating heat dissipation structure is equivalent to the fluid-solid thermal coupling effect between the inner layers of the pseudo three-dimensional model structure, and the movement of the porous medium material is controlled by introducing the effect of additional volume force in the porous medium material;

[0046] The established pseudo three-dimensional model structure is meshed and processed to discretize the pseudo three-dimensional model structure into small units, so as to realize single-objective optimization simulation of the pseudo three-dimensional model structure, determine the material volume factor value of the porous medium material, and obtain the upper and lower limit thresholds under two single-objective optimizations through single-objective optimization simulations, which serve as a reference for the normalization of the dual-objective function, and construct a topology optimization mathematical model. The dual-objective function in the topology optimization mathematical model is used to study the pseudo three-dimensional model structure under the influence of different weight ratios, and obtain multiple optimized optimization area planes. The comprehensive performance of parameters such as temperature difference, turbulent dissipated energy, and temperature uniformity are compared for the multiple optimized optimization area planes, so as to obtain the optimization area plane with the best comprehensive performance among the multiple optimized optimization area planes as the two-dimensional flow channel plane structure.

[0047] The optimized pseudo three-dimensional model is reconstructed, the obtained two-dimensional flow channel plane structure is three-dimensionally stretched, and the rotating heat dissipation structure is used as the source object to array the structure with repeated features to obtain the final optimized configuration.

[0048] Furthermore, the heat source plane in the pseudo three-dimensional model structure is equivalent to the outer wall of the disk surface located on the upper and lower sides of the heat dissipation channel in the rotating heat dissipation structure. The fan-shaped cross-sections relative to the upper and lower heat source planes are taken as the heat source input layer in the pseudo three-dimensional model structure, which is equivalent to replacing the heat source input area of ​​the three-dimensional model of the rotating heat dissipation structure. The fan-shaped cross-sections of the heat dissipation channel in the simplified rotating heat dissipation structure in the thickness direction and at the same height as the upper and lower disk surfaces are taken as the optimized area plane. The optimized area plane is between the upper and lower heat source planes, and the heat source plane is parallel to the optimized area plane, and the optimized area plane and the upper and lower heat source planes are required to have repeated features in the circumferential direction.

[0049] Furthermore, considering the heat exchange between the fluid structure and the solid structure, according to the topology optimization method, a ramp interpolation function is introduced for the thermal conductivity of the fluid structure and the solid structure materials. In the ramp interpolation function, the γ value is used as the dependent variable, and the thermal conductivity of the porous medium material initially corresponding to the plane of the optimization area is penalized to the two end values ​​of the thermal conductivity of the fluid structure and the thermal conductivity of the solid structure. The heat conduction between the heat source plane and the plane of the optimization area needs to be equivalent to the convective heat transfer coefficient between the heat dissipation channel and the heat source plane as a boundary condition, which is applied to the pseudo three-dimensional model structure to form heat exchange between layers in the pseudo three-dimensional structure. The following formula is used to determine the thermal conductivity of the porous medium material at the heat dissipation channel in the rotating heat dissipation structure and the convective heat transfer coefficient between the heat dissipation channel and the heat source plane through the interpolation function in the topology optimization method:

[0050]

[0051] Where: k(γ) is the interpolation of the thermal conductivity of the fluid structure material and the solid structure material at the heat dissipation channel, h(γ) is the interpolation of the nominal convection heat transfer coefficient between the heat dissipation channel and the heat source, γ is the material volume factor, and its value varies between 0 and 1. When γ tends to 0, the material is solid, and when γ tends to 1, the material is fluid. f is the thermal conductivity of the fluid material, k s is the thermal conductivity of the solid material, H is the distance between layers in the thickness direction, and h f is the convective heat transfer coefficient of the fluid at the structure, and C1 and C2 are the coefficients of the interpolation function.

[0052] Furthermore, in consideration of the fluid rotational motion, in order to facilitate the optimization of porous media materials, the pseudo-three-dimensional model structure is discretized into small units through grid division processing, and a single-objective optimization simulation of the pseudo-three-dimensional model structure is realized. In this way, the porous media motion required to be satisfied by the pseudo-three-dimensional model structure is corrected, and the material volume factor value of the porous media material is determined. In the correction process, the additional volume force is introduced into the porous media material, and the NS equation under the influence of rotational motion is established to control the motion of the porous media material.

[0053] In the NS equation under the influence of rotational motion, the Darcy interpolation is introduced by using the topology optimization method to penalize the additional volume force to the two end values ​​of the additional volume force terms corresponding to the fluid and the solid, thereby dividing the motion of the porous medium material into two parts: the rotational motion of the fluid and the solid, to ensure the accuracy of the pseudo-three-dimensional model motion simulation. At this time, under the influence of rotational motion, the NS equation expression corresponding to the porous medium material remains consistent;

[0054] Furthermore, taking the rotation center of the rotating heat dissipation structure as the origin, the coordinate system rotates around the origin at an angular velocity ω to establish the NS equation in the rotating coordinate system:

[0055]

[0056] Where ρ is the fluid density, T is the stress tensor, -2ρ(ω×v) is the Coriolis force term, -ρω×(ω×r) is the centrifugal force term, ρf is the volume force acting on each unit volume of the fluid, and f r (γ) is the additional volume force used to simulate porous media materials in topology optimization;

[0057] The additional volume force f used to simulate porous media materials in topology optimization r (γ) is determined according to the following formula:

[0058]

[0059] in, is the reverse osmosis rate, v abs is the absolute speed in the stationary coordinate system established with the rotation center of the rotating heat dissipation structure as the origin, v abs =v+ω×r, v is the linear velocity of the relative coordinates in the rotating coordinate system around the origin, ω is the angular velocity of the relative coordinates in the rotating coordinate system around the origin, and r is the rotation radius of the relative coordinates in the rotating coordinate system around the origin;

[0060] Determine according to the following formula

[0061]

[0062] Determine α according to the following formula max :

[0063]

[0064] Among them, α max , α min When γ takes values ​​between 0 and 1, The maximum and minimum values ​​of α min , its value is usually 0. In this operation, in order to improve the accuracy, α min =0, γ is the material volume factor, q is the penalty factor, μ is the fluid dynamic viscosity, Da is the Darcy value, and its value is less than 10 -5 , L is the characteristic length of the heat dissipation channel;

[0065] The value of the material volume factor γ is obtained by calculation, and the value of γ is made close to 0 by adjusting the parameters, so that the plane of the optimized area is a solid structure.

[0066] Furthermore, the upper and lower thresholds of the two single-objective optimizations are obtained through single-objective optimization simulations. The topology optimization method is used to perform single-objective optimization on the pseudo three-dimensional structure in terms of minimizing turbulent dissipation energy and minimizing thermal resistance, respectively, to obtain the turbulent dissipation energy objective function and the thermal resistance objective function. The thermal conductivity interpolation function of the fluid-solid material at the heat dissipation channel k(γ) is used as the initial material property for topology optimization, and the convective heat transfer coefficient interpolation function between the heat dissipation channel and the heat source h(γ) is used as the convective heat transfer boundary condition between the optimization layer and the heat source layer surface. A dual-objective optimization objective function is established.

[0067] The heat exchange capacity is:

[0068] q=∫h(γ)·(T2-T1)dΩ,

[0069] In the formula, T1 is the surface temperature of the heat source plane, and T2 is the temperature of the flow channel area;

[0070] The objective function of turbulent dissipated energy under single-objective optimization is as follows:

[0071]

[0072] The objective function of thermal resistance under single-objective optimization is as follows:

[0073]

[0074] Where, T in is the flow channel inlet temperature, A is the heat source surface area;

[0075] The turbulence dissipation energy objective function and thermal resistance objective function formed under single-objective optimization are normalized:

[0076]

[0077] In the formula, φ f is the objective function of turbulent energy dissipation, φ th is the thermal resistance objective function, φ f,min ,φ f,max are the minimum and maximum values ​​of the turbulence dissipation energy objective function (i.e., the upper and lower thresholds of the turbulence dissipation energy objective function under single-objective optimization), φ th,min ,φ th,min are the minimum and maximum values ​​of the thermal resistance objective function, respectively (i.e., the upper and lower thresholds of the thermal resistance objective function under single-objective optimization);

[0078] The general form of the dual-objective optimization objective function established based on this is as follows:

[0079] minobj:J=ω1φ1+ω2φ2

[0080]

[0081] Among them, ω1 is the weight of the turbulent dissipation energy objective function, ω2 is the weight of the thermal resistance temperature difference objective function, μ is the dynamic viscosity, and μ T is the turbulent viscosity, v abs is the absolute velocity in the stationary coordinate system, v is the relative velocity in the rotating coordinate system, and v abs =v+ωr, ω is the angular velocity of the rotating coordinate system, ρ is the fluid density, -2ρ(ω×v) is the Coriolis force term, -ρω×(ω×r) is the centrifugal force term, T1 is the surface temperature of the heat source, T2 is the temperature of the flow channel area, T is the stress tensor, z1 is the thickness of the flow channel plane, z2 is the thickness of the heat source part, f r (γ) is the additional volume force used to simulate porous media materials in topology optimization, k(γ) is the thermal conductivity of the material with respect to the change of volume factor, q flux is the heat flux density, h(γ) is the heat transfer coefficient affected by the material volume factor, C p is the specific heat capacity at constant pressure, γ min is the minimum value of the material volume factor, γ max is the maximum value of the material volume factor, which is used to control the proportion of solid and fluid materials in the flow channel, γ avg is the mean value of material volume factor.

[0082] Therefore, the dual objective function in the topology optimization mathematical model is used to study the pseudo three-dimensional model structure under the influence of different weight ratios, and multiple optimized optimization area planes are obtained. The comprehensive performance parameters of the multiple optimized optimization area planes are compared with each other, so as to obtain the optimization area plane with the best comprehensive performance among the multiple optimized optimization area planes as the two-dimensional flow channel plane structure.

[0083] Preferably, the area with a material volume factor γ value less than 0.5 in the optimized area plane is solid material, and the area with a γ value greater than 0.5 is fluid material. The optimized area plane is obtained, and the optimized area plane is further compared according to parameters such as disk temperature difference, turbulent dissipated energy, and temperature uniformity, so as to obtain the two-dimensional flow channel plane structure with the best comprehensive performance at the optimized area plane. Finally, the obtained two-dimensional flow channel plane structure is three-dimensionally stretched, and the obtained two-dimensional flow channel plane structure is used as the source object to array the structure with repeated features to obtain the final optimized configuration.

[0084] The present invention is further described in detail below through the accompanying drawings and the specific dual-objective optimization design of the heat dissipation flow channel structure of the ventilated brake disc of a high-speed train under the action of thermal fluid-solid coupling.

[0085] First, establish the design area outline dimensions and structural material parameters. Figure 2The left side is a schematic diagram of the fan-shaped structure of a single heat dissipation channel of the brake disc, in which the heat dissipation rib 1 and the brake disc surface (friction surface of the brake disc) 2 are the basic structures in the three-dimensional model of the brake disc, and a heat dissipation channel is provided between adjacent heat dissipation ribs 1. The design domain size is the actual size of the train ventilated brake disc, with an outer circumferential diameter of 0.33 meters and an inner circumferential diameter of 0.19 meters. The optimized area is the initial channel area of ​​the ventilated brake disc, with an outer circumferential radius of 0.21 meters and an inner circumferential radius of 0.315 meters. The thickness of the brake disc surface 2 is 15 mm, and the thickness of the heat dissipation channel is 48 mm. After extracting the structure according to step 1, the attached Figure 2 The pseudo three-dimensional structure on the right side, in the pseudo three-dimensional model structure, the plane where the brake disc surface is located is equivalent to the heat dissipation plane 3, and the flow channel plane in the heat dissipation channel is equivalent to the optimization area plane 4. The material is Q345B, with a density of 7800 kg / m3, thermal conductivity of 43.8 W / (mKelvin), and specific heat capacity of 487 J / (kg Celsius). The heat dissipation fluid is air, with a density of 1.225 (kg / m3), thermal conductivity of 0.024 W / (mKelvin), constant pressure heat capacity of 1006 J / (kg Celsius), and dynamic viscosity of 1.789*10^-5 (Pa seconds).

[0086] The model is meshed with quadrilateral meshes, with a mesh size of 0.0004 m × 0.0004 m. According to the actual working conditions of the high-speed train brake disc, the heat flux density is applied to the heat source plane 3, and a constant speed is given to the heat dissipation flow channel area. The velocity inlet and pressure outlet boundary conditions are applied to the optimization area plane 4. After dual-objective topology optimization calculation, it is obtained Figure 3 The schematic diagram of the optimization results under the effect of fluid-solid-heat coupling of the present invention is shown. Figure 3 Results The brake disc can be reconstructed to obtain Figure 4 The schematic diagram of the reconstruction of the ventilated brake disc for high-speed trains is shown to improve heat dissipation efficiency and extend the service life of the structure.

[0087] In summary, the dual-objective topology optimization design method of the structure under thermal-fluid-solid coupling can obtain the structural distribution of the heat dissipation flow channel of the high-speed and heavy-load brake disc under braking conditions, which meets the heat dissipation performance requirements of the brake disc.

[0088] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A dual-objective rotating heat dissipation channel structure optimization design method, characterized in that: The following steps are involved: The geometric model of the rotating heat dissipation structure is simplified, and the simplified three-dimensional model of the rotating heat dissipation structure is converted into a pseudo three-dimensional model structure through a multi-layer fluid-solid plane structure, and the heat source plane and the optimization area plane in the pseudo three-dimensional model structure are obtained, and the initial material of the optimization area plane is defined as a porous medium material between the fluid structure and the solid structure; The material parameters of the porous medium material are set according to the topology optimization method, and the thermal conductivity of the porous medium material at the heat dissipation channel in the rotating heat dissipation structure is determined. At the same time, the heat conduction effect between the heat source plane and the optimization area plane along the thickness direction is equivalent to the convection heat transfer coefficient between the heat dissipation channel and the heat source plane, which is applied to the pseudo three-dimensional model structure, so that the simplified three-dimensional model of the rotating heat dissipation structure is equivalent to the fluid-solid thermal coupling effect between the inner layers of the pseudo three-dimensional model structure, and the movement of the porous medium material is controlled by introducing the effect of additional volume force in the porous medium material; The established pseudo three-dimensional model structure is meshed and processed to discretize the pseudo three-dimensional model structure into small units, so as to realize single-objective optimization simulation of the pseudo three-dimensional model structure, determine the material volume factor value of the porous medium material, and obtain the upper and lower thresholds under two single-objective optimizations through single-objective optimization simulations, which serve as a reference for the normalization of the dual-objective function, and construct a topology optimization mathematical model. The dual-objective function in the topology optimization mathematical model is used to study the pseudo three-dimensional model structure under the influence of different weight ratios, obtain multiple optimized optimization area planes, and compare the comprehensive performance parameters of the multiple optimized optimization area planes, so as to obtain the optimization area plane with the best comprehensive performance among the multiple optimized optimization area planes as the two-dimensional flow channel plane structure; The optimized pseudo three-dimensional model is structurally reconstructed, that is, the obtained two-dimensional flow channel plane structure is three-dimensionally stretched, and the obtained two-dimensional flow channel plane structure is used as the source object to array the structure with repeated features to obtain the final optimized configuration as the preferred rotating heat dissipation structure.

2. A dual-objective rotating heat dissipation channel structure optimization design method according to claim 1, characterized in that: The heat source plane in the pseudo three-dimensional model structure is equivalent to the outer wall of the disk located on the upper and lower sides of the heat dissipation channel in the rotating heat dissipation structure. The fan-shaped cross-sections relative to the upper and lower heat source planes are taken as the heat source input layer in the pseudo three-dimensional model structure, which is equivalent to replacing the heat source input area of ​​the three-dimensional model of the rotating heat dissipation structure.

3. A dual-objective rotating heat dissipation channel structure optimization design method according to claim 2, characterized in that: The method for obtaining the optimized area plane in the pseudo three-dimensional model structure is: The fan-shaped cross-section of the heat dissipation channel in the simplified rotating heat dissipation structure in the thickness direction and at the same height as the upper and lower disk surfaces is used as the optimization area plane. The optimization area plane is between the upper and lower heat source planes, and the heat source plane is parallel to the optimization area plane, and the optimization area plane and the upper and lower heat source planes are required to have repeated features in the circumferential direction.

4. The dual-objective rotating heat dissipation channel structure optimization design method according to claim 1 is characterized in that: The following formula is used to determine the thermal conductivity of the porous medium material at the heat dissipation channel in the rotating heat dissipation structure and the convection heat transfer coefficient between the heat dissipation channel and the heat source plane through the interpolation function in the topology optimization method: Where: k(γ) is the thermal conductivity interpolation function of the porous medium material at the heat dissipation channel, h(γ) is the convective heat transfer coefficient interpolation function between the heat dissipation channel and the heat source plane, γ is the material volume factor, and its value varies between 0 and 1. When γ tends to 0, the material is solid, and when γ tends to 1, the material is fluid. f is the thermal conductivity of the fluid material, k s is the thermal conductivity of the solid material, H is the distance between layers in the thickness direction, and h f is the convective heat transfer coefficient of the fluid at the structure, and C1 and C2 are the coefficients of the interpolation function.

5. A dual-objective rotating heat dissipation channel structure optimization design method according to claim 4, characterized in that: According to the single-objective optimization simulation, the material volume factor γ is determined using the following formula, and the value of the pseudo-three-dimensional model structure is discretized into small units. in, ρ is the fluid density, T is the stress tensor, -2ρ(ω×v) is the Coriolis force term, -ρω×(ω×r) is the centrifugal force term, ρf is the volume force acting on each unit volume of the fluid, and f r (γ) is the additional volume force of the porous medium material introduced; is the reverse osmosis rate, v abs is the absolute speed in the stationary coordinate system established with the rotation center of the rotating heat dissipation structure as the origin, v abs =v+ω×r, v is the linear velocity of the relative coordinates in the rotating coordinate system around the origin, ω is the angular velocity of the relative coordinates in the rotating coordinate system around the origin, and r is the rotation radius of the relative coordinates in the rotating coordinate system around the origin; α max , α min When γ takes values ​​between 0 and 1, The maximum and minimum values ​​of min =0, γ is the material volume factor, q is the penalty factor, μ is the fluid dynamic viscosity, Da is the Darcy value, and its value is less than 10 -5 , L is the characteristic length of the heat dissipation channel.

6. A dual-objective rotating heat dissipation channel structure optimization design method according to claim 5, characterized in that: According to the following formula, a dual-objective optimization objective function is established through the topology optimization method, and the pseudo three-dimensional model structure is studied under the influence of different weight ratios to determine the optimized area plane with the best comprehensive performance. minobj:J=ω1φ1+ω2φ2 in, ω1 is the weight of the turbulent dissipation energy objective function, ω2 is the weight of the thermal resistance temperature difference objective function, T1 is the surface temperature of the heat source plane, T2 is the temperature of the heat dissipation channel area, μ is the dynamic viscosity, μ T is the turbulent viscosity, v abs is the absolute velocity in the stationary coordinate system, v is the relative velocity in the rotating coordinate system, and v abs =v+ω×r, ω is the angular velocity of the rotating coordinate system, -2ρ(ω×v) is the Coriolis force term, -ρω×(ω×r) is the centrifugal force term, T is the stress tensor, z1 is the thickness of the heat dissipation channel plane, z2 is the thickness of the heat source part, ρf is the volume force per unit volume acting on the fluid material, f r (γ) is the additional volume force used to simulate porous media materials in topology optimization, k(γ) is the thermal conductivity of the material with respect to the change of volume factor, q flux is the heat flux density, h(γ) is the heat transfer coefficient affected by the material volume factor, C p is the specific heat capacity at constant pressure, γ min is the minimum value of the material volume factor, γ max is the maximum value of the material volume factor, which is used to control the proportion of solid and fluid materials in the flow channel, γ avg is the mean value of the material volume factor, φ f is the objective function of turbulent energy dissipation, φ th is the thermal resistance objective function, φ f,min ,φ f,max are the minimum and maximum values ​​of the turbulence dissipation energy objective function, respectively, th,min ,φ th,min are the minimum and maximum values ​​of the thermal resistance objective function, T in is the flow channel inlet temperature, A is the heat source surface area, k s is the thermal conductivity of the solid material.

7. A dual-objective rotating heat dissipation channel structure optimization design method according to claim 4, characterized in that: The area in the plane of the optimized region where the material volume factor γ value is less than 0.5 is solid material, and the area where the γ value is greater than 0.5 is fluid material.

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