A large-area thin-walled uniform heating plate structure design and optimization method

Abstract

The application discloses a large-area thin-wall heat plate structure design and optimization method, and relates to the technical field of spaceflight.The method comprises the following steps: step 1, determining application conditions and parameters; step 2, determining processing link constraint conditions; step 3, determining an optimal design point of the large-area thin-wall heat plate structure design; step 4, checking and correcting the structure parameters of a cavity under the condition of a temperature field, and solving the maximum stress of the cavity; step 5, if the maximum stress of the cavity does not meet the design requirements, returning to step 3, correcting the design parameters, and repeating steps 3 and 4, and if the maximum stress of the cavity meets the design requirements, obtaining a design result.The application can be applied to the heat plate cavity structure design under different parameter requirements, guarantees that the mechanical bearing and steam diffusion performance of the heat plate cavity structure reach the best performance state, and provides a complete design and optimization method for the large-area thin-wall heat plate.

Description

Technical Field

[0001] This invention relates to the field of aerospace technology, and in particular to a method for designing and optimizing a large-area thin-walled heat exchanger structure. Background Technology

[0002] With the rapid development of aerospace technology, the integration and power of electronic devices within spacecraft are constantly increasing. This makes traditional heat dissipation methods, such as embedding heat pipes in single-phase heat diffusion modules, insufficient to meet the high-power heat dissipation demands of various heat sources. Therefore, a reliable heat control method with efficient temperature uniformity, heat diffusion, and rapid response is urgently needed. A vapor chamber, as a two-phase passive heat diffusion device based on an internal capillary structure that enables spontaneous circulation of evaporation / boiling, vapor diffusion, and condensation processes, can rapidly expand localized high heat flux two-dimensionally to a larger cooling area. Simultaneously, its surface has excellent flatness, providing a promising solution to the heat dissipation challenges of high-power device mounting plates in next-generation spacecraft.

[0003] However, current ground-based vapor chambers are mainly designed for small electronic components such as CPUs, with heat sink areas of approximately 10cm x 10cm. They typically use water or acetone as the working fluid, and due to the influence of the working fluid and operating conditions, the internal vapor pressure is often negative. Therefore, existing vapor chambers, due to their small size and low vapor pressure, neglect the design of their thin-walled cavity load-bearing structure. When applying to space environments, high-pressure working fluids such as ammonia are required, rendering conventional vapor chamber designs unsuitable. This significantly increases the risks of deformation, bulging, and leakage. Furthermore, the need for larger heat dissipation areas and thinner walls in multi-heat source integrated installations makes a reasonable and reliable cavity structure design and optimization the primary issue limiting the widespread application of large-area vapor chambers. Existing invention patents, such as CN202010632076.1 and CN202011078964.X, only focus on structural optimization for flow or heat transfer performance, neglecting mechanical load-bearing capacity and the coupling effects between structural mechanics, flow, and thermodynamics.

[0004] Therefore, those skilled in the art are dedicated to developing a design and optimization method for large-area thin-walled heat exchanger structures that is applicable to different application conditions and operating parameters, comprehensively considers mechanical load-bearing capacity and vapor diffusion performance, and has guiding significance. Summary of the Invention

[0005] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is how to design a large-area thin-walled heat exchanger cavity structure that satisfies the optimal stress-strain reliability and steam diffusion resistance in a space environment.

[0006] To achieve the above objectives, the present invention provides a method for designing and optimizing a large-area thin-walled heat exchanger structure, characterized in that the method includes the following steps:

[0007] Step 1: Determine the application conditions and parameters;

[0008] Step 2: Determine the constraints of the processing stage;

[0009] Step 3: Determine the optimal design point for the large-area thin-walled heat spreader structure;

[0010] Step 4: Considering the temperature field, check and correct the cavity structure parameters of the large-area thin-walled heat exchanger, and solve for the maximum cavity stress of the large-area thin-walled heat exchanger.

[0011] Step 5: If the maximum stress of the cavity does not meet the design requirements, return to step 3, correct the selection of design parameters, and repeat steps 3 and 4. If the maximum stress of the cavity meets the design requirements, the design result is obtained.

[0012] Further, in step 1, the parameters include the material parameters used in processing the cavity, the heat source parameters, and the heat exchange working fluid parameters; the material parameters used in processing the cavity include the cavity material density and the yield strength of the cavity material of the large-area thin-walled heat spreader; the heat source parameters include the heat source size, the maximum heat source temperature, and the heat dissipation power of the heat source; the heat exchange working fluid parameters include the saturated vapor pressure of the working fluid at the heat source temperature.

[0013] Furthermore, in step 2, the constraints of the processing stage include direct constraints, which are constraints that directly limit three basic design parameters. The three basic design parameters include the diameter of the load-bearing column, the thickness of the upper and lower plates, and the porosity of the large-area thin-walled heat spreader.

[0014] Furthermore, in step 2, the constraints of the processing stage also include indirect constraints. The indirect constraints are constraints that are not directly related to the three basic design parameters but can be solved by functions of the three basic design parameters. The indirect constraints include the minimum spacing between load-bearing columns and the maximum average volume density of the large-area thin-walled heat exchange plate.

[0015] Furthermore, step 3 also includes:

[0016] Step 3.1: Select the corresponding control parameter method according to the constraints of the processing stage. The control parameter method is one of controlling the diameter of the load-bearing column, controlling the thickness of the upper and lower plates, and controlling the porosity.

[0017] Step 3.2: Obtain the influence diagram of each parameter under the control parameter method;

[0018] Step 3.3: Locate the design area and find the optimal design point.

[0019] Furthermore, in step 3.1, the control parameter method is selected based on the processing conditions. If the processing conditions constrain the diameter of the load-bearing column, the thickness of the upper and lower plates, and the porosity, then a value of the constrained parameter within the processing range is selected. If the processing conditions do not directly constrain the three basic design parameters, then a value of any one of the three basic design parameters is selected.

[0020] Further, in step 3.2, after selecting one of the three basic design parameters, the control parameter method uses the other two basic design parameters as the horizontal and vertical axes, respectively, and solves the stress curve according to the maximum stress correlation formula of the large-area thin-walled heat exchange plate. The maximum stress correlation formula is:

[0021]

[0022] Where σ MAX The maximum stress in the cavity of the large-area thin-walled heat exchanger is given by P, where P is the vapor pressure inside the cavity, and h is the pressure inside the cavity. s ε is the thickness of the upper and lower plates of the cavity. s For porosity, d s Let be the diameter of the load-bearing column, where the porosity is:

[0023]

[0024] Where S1 is the projected area of ​​the regular hexagonal working region of the load-bearing column element, and S2 is the cross-sectional area of ​​the load-bearing column.

[0025] The pressure drop curve is obtained by solving the steam flow pressure drop correlation within the large-area thin-walled heat exchanger plate. The steam flow pressure drop correlation is as follows:

[0026]

[0027] Where Δp is the vapor pressure drop, H is the total thickness of the large-area thin-walled heat exchanger, and e is the natural constant, with a value of 2.71828.

[0028] Other constraint curves are solved based on the indirect constraint conditions, wherein the formula for calculating the average bulk density of the large-area thin-walled heat exchange plate is:

[0029]

[0030] Where ρ c ρ is the average bulk density of the large-area thin-walled heat exchanger. m The density of the cavity material of the large-area thin-walled heat exchange plate;

[0031] The formula for calculating the spacing between load-bearing columns is:

[0032]

[0033] Among them l s This represents the spacing between adjacent load-bearing columns.

[0034] Furthermore, in step 3.3, the design area refers to the area that meets the design requirements in the influence law diagram of each parameter.

[0035] Furthermore, in step 3.3, the optimal design point is the point found based on the pressure drop curve that meets the allowable stress of the material and has the minimum flow pressure drop within the design region.

[0036] Furthermore, step 4 also includes establishing a finite element simulation model based on the parameters of the optimal design point, selecting the maximum allowable temperature of the heat-generating element of the large-area thin-walled heat exchanger as the heat source side boundary temperature of the finite element simulation model, using the cold source temperature in the actual application scenario as the cold source side boundary temperature of the finite element simulation model, forming the maximum heat transfer temperature difference from the heat source side to the cold source side in the finite element simulation model, using the saturated vapor pressure corresponding to the heat source temperature as the inner vapor working fluid pressure of the large-area thin-walled heat exchanger, and solving the finite element simulation model based on finite element simulation software to obtain the maximum stress of the cavity.

[0037] Existing technologies are all geared towards single heat sources, resulting in small heat dissipation devices that are susceptible to variations in working fluid and operating conditions, while neglecting internal negative pressure and mechanical load-bearing design. However, integrated applications with multiple heat sources in space environments require high-pressure working fluids and large heat dissipation areas, making the mechanical performance of thin-walled cavity structures a primary concern for ensuring cavity safety and reliability. This invention employs parametric design of the entire cavity's load-bearing structure. Based on proposed parameter matching correlations and optimization processes, it achieves multi-objective optimization of cavity mechanical performance and intracavity vapor flow diffusion performance. Through parametric analysis, it obtains correlations for maximum cavity stress and intracavity vapor flow pressure drop. Subsequently, by applying objective variables and constraints, it determines the optimal design point within the plotted parameter influence diagram, thus establishing the best matching relationship for each geometric parameter. This achieves the dual objectives of minimizing cavity mechanical reliability and intracavity vapor flow diffusion resistance, yielding optimized structural parameters.

[0038] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0039] Figure 1 This is a flowchart illustrating a preferred embodiment of the present invention regarding the design and optimization method of a large-area thin-walled heat exchange plate structure.

[0040] Figure 2This is a schematic diagram of the heat exchanger cavity structure parameters of a preferred embodiment of the present invention, which describes a method for designing and optimizing a large-area thin-walled heat exchanger structure.

[0041] Figure 3 This is a diagram showing the influence of various parameters when the diameter of the load-bearing column is known, representing a preferred embodiment of the present invention for the design and optimization method of a large-area thin-walled heat exchange plate structure.

[0042] Figure 4 This is a diagram showing the region division and optimal point selection when the diameter of the load-bearing column is known, representing a preferred embodiment of the present invention, of a large-area thin-walled heat exchanger structure design and optimization method.

[0043] Among them, 1-support column, 2-capillary wick, 3-evaporation surface. Detailed Implementation

[0044] The following description, with reference to the accompanying drawings, illustrates several preferred embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0045] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, the thickness of some components has been appropriately exaggerated in the drawings.

[0046] The purpose of this invention is to provide a method for designing and optimizing a large-area thin-walled heat exchanger structure. This invention relates to the macroscopic structural design within the heat exchanger, and is not affected by the form and distribution of microcapillary structures on the walls of the cavity. It has good compatibility with the microcapillary core within the cavity, aiming to provide a cavity structure solution that satisfies both stress-strain reliability and optimal vapor diffusion resistance. This invention includes the following steps: determining application conditions and parameters, including determining the material parameters, heat source parameters, and heat exchange medium parameters used in the processing cavity; determining processing constraints, including direct and indirect constraints; selecting the corresponding control parameter design method based on the processing constraints; obtaining the influence law diagram of each parameter under a certain parameter, locating the design area that meets the requirements, and finding the optimal design point; considering the verification and correction of the cavity's structural parameters under temperature field conditions, constructing a thermo-mechanical coupling simulation model of the heat exchanger, and correcting the selection of design parameters until the optimal design point meets the maximum stress requirement.

[0047] like Figure 1 As shown, the design and optimization method for a large-area thin-walled heat exchanger structure according to the present invention includes the following specific steps:

[0048] Step 1: Determine the application conditions and parameters, specifically: determine the material parameters used for the processing cavity, including the cavity material density and yield strength; determine the heat source parameters, including the heat source size, the maximum heat source temperature, and the heat dissipation power of the heat source; determine the heat exchange working fluid parameters, including the saturated vapor pressure of the working fluid at the heat source temperature.

[0049] Step 2: Determine the constraints of the processing stage. The constraints of the processing stage include two types: direct constraints and indirect constraints. Direct constraints directly limit the three basic design parameters: the diameter of the load-bearing column, the thickness of the upper and lower plates, and the porosity. Examples include the minimum diameter of the load-bearing column and the minimum thickness of the cavity plate. Indirect constraints are constraints that are not directly related to the three basic design parameters but can be solved using functions of the three basic parameters, such as the minimum spacing between load-bearing columns and the maximum average bulk density.

[0050] Step 3: Optimal design point selection for large-area thin-walled heat exchanger structure design, specifically including the following steps:

[0051] Step 3.1: Select the corresponding control parameter method based on the processing conditions. Specifically, depending on whether the processing conditions constrain the three basic design parameters—the diameter of the load-bearing column, the thickness of the upper and lower plates, and the porosity—if there are direct constraints in the processing stage of Step 2, select a value for the constrained parameter that is within the processable range; otherwise, determine a value for any of the three basic design parameters. This results in three control parameter design methods: controlling the diameter of the load-bearing column, controlling the thickness of the upper and lower plates, and controlling the porosity.

[0052] Step 3.2: Obtain the influence diagram of each parameter under a certain parameter. Specifically, take the other two basic design parameters as the horizontal and vertical axes, respectively, and solve the stress curve according to the maximum stress correlation formula of the heat exchanger. The maximum stress correlation formula of the heat exchanger is:

[0053]

[0054] Where σ MAX The maximum stress in the heat spreader cavity is given by P (unit: MPa), where P is the vapor pressure inside the cavity (unit: MPa), and h is the pressure inside the cavity. s ε represents the thickness of the upper and lower plates of the cavity (unit: mm). s For porosity, d s The diameter of the load-bearing column (unit: mm) is shown in the diagram below. Figure 2 As shown, the porosity is:

[0055]

[0056] Where S1 is the projected area of ​​the regular hexagonal working region of the load-bearing column element (unit: mm2), and S2 is the cross-sectional area of ​​the load-bearing column element (unit: mm2).

[0057] The pressure drop curve is obtained by solving the correlation equation for the pressure drop of steam flow inside the heat exchanger. The correlation equation for the pressure drop of steam flow inside the heat exchanger is as follows:

[0058]

[0059] Where Δp is the vapor pressure drop (in Pa), H is the total thickness of the heat spreader (in mm), and e is the natural constant, which is approximately 2.71828.

[0060] Solve for other constraint curves based on indirect constraint conditions, where the formula for calculating the average bulk density of the heat exchange plate is:

[0061]

[0062] Where ρ c ρ is the average bulk density of the heat exchange plate (unit: g / cm3). m Density of the cavity material (unit: g / cm3).

[0063] The formula for calculating the spacing between load-bearing columns is:

[0064]

[0065] Among them l s The distance between adjacent load-bearing columns (unit: mm).

[0066] If other indirect constraints exist, they can also be represented by the functional relationship between the objective variable and the basic structural parameters of the cavity, thereby solving for other constraint curves.

[0067] When the diameter of the load-bearing column is 5mm, the stress curve, pressure drop curve, and density contour lines can be plotted with the plate thickness as the abscissa and the porosity as the ordinate, thus obtaining a diagram showing the influence of various parameters on the known load-bearing column diameter. Figure 3 As shown.

[0068] Step 3.3: Find the optimal design point within the design area. Specifically, based on the influence diagram of each parameter, find the design area that meets the design requirements. Based on the pressure drop curve, find the point within the design area that meets the allowable stress of the material and has the minimum flow pressure drop as the optimal design point. Figure 3 The graph showing the influence of various parameters divides the image into multiple regions using three curves. Based on the correlations for the maximum stress of the heat exchanger and the pressure drop of steam flow within the heat exchanger, the practical significance of each region can be further determined, and the design region and optimal design point can be identified. Figure 4 As shown, the marked position is the optimal design point under the current circumstances.

[0069] Step 4: Consider the temperature field factors in specific application scenarios to check and correct the structural parameters of the cavity. Specifically, establish a finite element simulation model based on the optimal design point parameters determined in Step 3. Select the maximum allowable temperature of the heat-generating element in the actual application scenario of the heat spreader as the boundary temperature of the heat source side of the model, and use the cold source temperature in the actual application scenario as the boundary temperature of the cold source side. The maximum heat transfer temperature difference is formed from the heat source side to the cold source side in the unit model. Under this condition, the thermal stress in the load-bearing unit is the worst. At the same time, the saturated vapor pressure at the heat source temperature is used as the vapor working fluid pressure inside the heat spreader. Solve the above thermo-mechanical coupling simulation model based on the finite element simulation software to obtain the maximum stress of the cavity.

[0070] Step 5: Determine whether the maximum stress result of the cavity meets the design requirements. If not, modify the selection of design parameters in Step 3, and repeat Step 3 and Step 4 until the maximum stress meets the requirements.

[0071] The beneficial effects of this invention are as follows: Taking a large-area thin-walled heat exchanger as the design object, it comprehensively considers the mechanical properties of the heat exchanger cavity and the vapor flow and diffusion performance inside the cavity under the coupling effect of different pressure fields and temperature fields. It associates all target variables with the three basic designs of the support column diameter, plate thickness, and porosity, and divides a reasonable design domain by means of curves, which more effectively solves the multi-objective optimization problem in the design process of large-area thin-walled heat exchangers.

[0072] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for designing and optimizing a large-area thin-walled heat spreader structure, characterized in that, The method includes the following steps: Step 1: Determine the application conditions and parameters; Step 2: Determine the constraints of the processing stage. The constraints of the processing stage include direct constraints, which are constraints that directly limit the three basic design parameters. The three basic design parameters include the diameter of the load-bearing columns, the thickness of the upper and lower plates, and the porosity of the large-area thin-walled heat exchanger plate. The constraints of the processing stage also include indirect constraints, which are constraints that are not directly related to the three basic design parameters but can be solved by functions of the three basic design parameters. The indirect constraints include the minimum spacing between the load-bearing columns and the maximum average bulk density of the large-area thin-walled heat exchanger plate. Step 3: Determine the optimal design point for the large-area thin-walled heat exchanger structure; Step 3.1: Select the corresponding control parameter method according to the constraints of the processing stage. The control parameter method is one of controlling the diameter of the load-bearing column, controlling the thickness of the upper and lower plates, and controlling the porosity. Step 3.2: Obtain the influence diagram of each parameter under the control parameter method. The control parameter method selects one of the three basic design parameters, and then uses the other two basic design parameters as the horizontal and vertical axes, respectively. The stress curve is then calculated based on the maximum stress correlation formula of the large-area thin-walled heat exchanger. The maximum stress correlation formula is: in This represents the maximum stress within the cavity of the large-area thin-walled heat exchanger. This refers to the vapor pressure inside the cavity. The thickness of the upper and lower plates of the cavity. Porosity Let be the diameter of the load-bearing column, where the porosity is: in Let be the projected area of ​​the regular hexagonal working region of the load-bearing column element. This is the cross-sectional area of ​​the load-bearing column. The pressure drop curve is obtained by solving the steam flow pressure drop correlation within the large-area thin-walled heat exchanger plate. The steam flow pressure drop correlation is as follows: in For vapor pressure drop, Let be the total thickness of the large-area thin-walled heat spreader, and let e be the natural constant, with a value of 2.71828. Other constraint curves are solved based on the indirect constraint conditions, wherein the formula for calculating the average bulk density of the large-area thin-walled heat exchange plate is: in The average bulk density of the large-area thin-walled heat exchanger plate. The density of the cavity material of the large-area thin-walled heat spreader is given. The formula for calculating the spacing between load-bearing columns is: in The distance between adjacent load-bearing columns; Step 3.3: Locate the design area and find the optimal design point; Step 4: Considering the temperature field, check and correct the cavity structure parameters of the large-area thin-walled heat exchanger, and solve for the maximum cavity stress of the large-area thin-walled heat exchanger. Step 5: If the maximum stress of the cavity does not meet the design requirements, return to step 3, correct the selection of design parameters, and repeat steps 3 and 4. If the maximum stress of the cavity meets the design requirements, the design result is obtained.

2. The method for designing and optimizing a large-area thin-walled heat spreader structure as described in claim 1, characterized in that, In step 1, the parameters include the material parameters of the processing cavity, the heat source parameters, and the heat exchange working fluid parameters; the material parameters of the processing cavity include the cavity material density and the yield strength of the cavity material of the large-area thin-walled heat spreader; the heat source parameters include the heat source size, the maximum heat source temperature, and the heat dissipation power of the heat source; the heat exchange working fluid parameters include the saturated vapor pressure of the working fluid at the heat source temperature.

3. The method for designing and optimizing a large-area thin-walled heat spreader structure as described in claim 1, characterized in that, In step 3.1, the control parameter method is selected based on the processing conditions. If the processing conditions constrain the diameter of the load-bearing column, the thickness of the upper and lower plates, and the porosity, then a value of the constrained parameter within the processing range is selected. If the processing conditions do not directly constrain the three basic design parameters, then a value of any one of the three basic design parameters is selected.

4. The method for designing and optimizing a large-area thin-walled heat spreader structure as described in claim 1, characterized in that, In step 3.3, the design area refers to the area that meets the design requirements in the influence law diagram of each parameter.

5. The method for designing and optimizing a large-area thin-walled heat spreader structure as described in claim 4, characterized in that, In step 3.3, the optimal design point is the point found in the design region based on the pressure drop curve that meets the allowable stress of the material and has the minimum flow pressure drop.

6. The method for designing and optimizing a large-area thin-walled heat spreader structure as described in claim 1, characterized in that, Step 4 further includes establishing a finite element simulation model based on the parameters of the optimal design point, selecting the maximum allowable temperature of the heat-generating element of the large-area thin-walled heat exchanger as the heat source side boundary temperature of the finite element simulation model, using the cold source temperature in the actual application scenario as the cold source side boundary temperature of the finite element simulation model, forming the maximum heat transfer temperature difference from the heat source side to the cold source side in the finite element simulation model, using the saturated vapor pressure corresponding to the heat source temperature as the inner vapor working fluid pressure of the large-area thin-walled heat exchanger, and solving the finite element simulation model based on finite element simulation software to obtain the maximum stress of the cavity.

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