TPMS infinitesimal heat exchanger design method based on fluid stroke control

Abstract

The invention provides a TPMS (Tire Pressure Monitor System) infinitesimal heat exchanger design method based on fluid stroke control, which comprises the following steps of: enumerating feasible baffle plate schemes by utilizing a random search algorithm to form a baffle plate configuration set; based on the baffle configuration set, generating a corresponding baffle model, filling a TPMS unit structure in the shell model, and performing volume mesh division on the filled model; grid independence verification is carried out on the divided volume grids, simulation is carried out, pressure drop, Nusselt number and PEC indexes are calculated, and a rule between baffle adding and heat exchange performance of the heat exchanger is determined according to the indexes; and on the basis of the rule, performing dual-scale optimization of stroke length priority and coarse-grained region division on the baffle configuration set until an optimal scheme is obtained. The TPMS structural unit is filled in a heat exchanger component, the stroke of fluid in the heat exchanger is controlled by adding the baffle, and the overall heat exchange performance is improved on the premise that manufacturing constraint is guaranteed.

Description

Technical Field

[0001] The invention belongs to the field of heat exchanger design, and in particular relates to a TPMS micro-element heat exchanger design method based on fluid stroke control. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] As a device for heat exchange between hot and cold fluids, heat exchangers play an important role in many industrial fields such as chemical industry, energy, electronics, aerospace, etc., and are essential for maintaining safe, stable and energy-saving operation of engines, air-conditioning systems and other important components. The design of heat exchangers pursues compactness, lightness and efficiency. With the rapid development of today's industrial field and the increasing heat load, how to achieve high-performance heat exchange in a limited design space has always been a challenging task. However, traditional plate and tube heat exchangers are increasingly unable to cope with higher heat exchange requirements, which has promoted the exploration of new heat exchange structure design and optimization solutions.

[0004] At present, the focus of researchers on heat exchangers is to improve the heat transfer performance. In recent years, triply periodic minimal surface (TPMS) has become the research focus in the field of heat exchanger design because of its high specific surface area, light weight, high smoothness, excellent heat and mass transfer performance and comprehensive mechanical properties. There are two technical solutions in this regard. One is to start from the TPMS unit structure and find or design a TPMS type with the best heat transfer performance as the basic filling unit of the heat exchanger; the other is to start from the overall structure of the heat exchanger and use methods such as topology optimization to optimize the overall heat transfer performance. The former has the disadvantage that it focuses on the design and optimization of the local unit structure, which will lead to low overall heat transfer performance after the heat exchange component is filled; and the latter, although it can optimize the overall heat transfer performance of the heat exchanger through complex algorithms, does not consider the constraints on the manufacturing of the heat exchanger when optimizing it using methods such as topology optimization, which is difficult in practical applications, and the optimization process will bring huge computational complexity. Therefore, how to achieve a heat exchanger that meets manufacturing constraints and takes into account overall heat transfer performance within the design space has always been a technical problem that needs to be solved in the design of heat exchangers. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a TPMS micro-element heat exchanger design method based on fluid stroke control. The present invention fills TPMS structural units inside the heat exchanger component, controls the fluid stroke inside the heat exchanger by adding baffles, and improves the overall heat exchange performance while ensuring manufacturing constraints.

[0006] According to some embodiments, the present invention adopts the following technical solutions:

[0007] A TPMS micro-element heat exchanger design method based on fluid stroke control includes the following steps:

[0008] Using random search algorithm, feasible baffle solutions are enumerated to form a baffle configuration set;

[0009] Based on the baffle configuration set, the corresponding baffle model is generated, and the TPMS unit structure inside the shell model is filled, and the filled model is meshed;

[0010] Verify the mesh independence of the divided volume mesh, perform simulation, calculate the pressure drop, Nusselt number and PEC index, and determine the relationship between the addition of baffles and the heat transfer performance of the heat exchanger based on the indexes;

[0011] Based on the above rules, the baffle configuration set is optimized at two scales, namely, stroke length priority and coarse-grained area division, until the optimal solution is obtained.

[0012] As an optional implementation, the feasible baffle solution needs to cover the entire design space as comprehensively as possible, while satisfying the requirements of traversing all filling units and that all filling units are interconnected.

[0013] As an optional implementation, using a random search algorithm, the process of enumerating feasible baffle solutions includes: abstracting the heat exchanger model into a two-dimensional regular grid G, and adding baffles at the intersection of adjacent grid points to control the flow;

[0014] Determine the 4-directional baffle configuration for the filling unit based on the connected neighborhood position, and add all structures to the structure table set T{t 1 ,t 2 ,t 3 ,…,t n}, determine the export Inlet structure t inlet And join the set Q;

[0015] Take element S from set Q i Perform BFS search based on the current S i The structure of i , determine the connected neighborhood unit S i+1 , randomly determine a structure t for it i+1 And add it to the queue Q until all connected neighborhoods are traversed.

[0016] As a further implementation, the scale of the two-dimensional regular grid G ​​is determined by the period of the TPMS and the size of the heat exchanger to ensure that each grid point fills a complete TPMS unit cell structure.

[0017] As a further implementation method, when performing a BFS search, if the solution is found to be infeasible during the search process, a backtracking operation is performed, and the search returns to the previously recorded state. An untraversed structure is determined for the current neighborhood unit and the search continues until the constraints are met and the search ends at the exit position, thereby forming a baffle configuration set.

[0018] As an optional implementation, the baffle model is generated by Boolean operation and translation according to the position of each baffle in the baffle configuration set.

[0019] As an optional implementation, the process of filling the TPMS unit structure inside the shell model includes filling the internal heat exchange unit of the grid with a Gyroid-type TPMS structure, and the mathematical expression is as follows:

[0020] φ(r)=sin(X)cos(Y)+sin(Z)cos(X)+sin(Y)cos(Z)=C

[0021] The three-dimensional shell coordinates are discretized into multiple coordinate points according to the set spacing d, and the function value of each point is calculated according to the set period, thickness and offset parameters to generate a signed distance field. The MarchingCube algorithm is executed on the obtained signed distance field to obtain the surface mesh M2 of the model;

[0022] Add a baffle, perform Boolean subtraction on the baffle model M1 and the surface mesh M2, and obtain model M by subtracting M1 from M2. Model M is the model after the TPMS structure is filled and the baffle is added.

[0023] As an optional implementation, the process of volume meshing the filled model includes setting six boundary layers in the surface mesh near the TPMS heat exchange surface to capture more detailed flow characteristics; setting a tetrahedral mesh at the TPMS heat exchange surface to accelerate calculations and generate a volume mesh V.

[0024] As an optional implementation method, the grid independence of the divided volume grid is verified, and simulations are performed using models with different numbers of grids to compare the pressure drop, inlet and outlet temperature difference, and Nusselt number to ensure the credibility of the volume grid. Under the same conditions, simulation boundary conditions are set for the designed example, and simulation is performed to calculate the pressure drop, Nusselt number, and PEC.

[0025] As an optional embodiment, the relationship between the addition of baffles and the heat transfer performance of the heat exchanger includes: (1) adding baffles can change the length of the stroke and change the flow distribution, so that the heat exchange unit can be more fully utilized;

[0026] (2) The longer the stroke, the higher the Nusselt number and PEC, but the pressure drop also increases;

[0027] (3) For strokes of the same length, the later the baffle affects the flow, the higher the PEC.

[0028] As an optional implementation, based on the rule, the baffle configuration set is optimized at a dual scale of stroke length priority and coarse-grained region division until the optimal solution is obtained, including: dividing each grid point of the abstracted grid into a number of regions, establishing a mapping relationship, and forming a coarse-grained regular grid, so that the fluid stroke length is reduced, thereby reducing the pressure drop;

[0029] For the design requirement that the entrance and exit are located at any two corners of a regular grid, the idea of ​​scanning lines is used to generate an alternating path from the exit to the entrance. After touching the boundary of graph G, the direction of travel is reversed or changed vertically until the exit is reached. After the end, the baffle configuration is generated according to the path;

[0030] For the design requirement that the entrance and exit are located at any boundary position of the regular grid, the divide-and-conquer idea is adopted to divide the sub-areas and decompose them into the design requirement that the entrance and exit are located at any two corners of the grid.

[0031] In the dual-scale optimization process of stroke length priority and coarse-grained area division for the baffle configuration set, the surface mesh and volume mesh of the baffle obtained by the optimized baffle addition algorithm are generated for simulation analysis. After each optimization, the pressure drop and PEC value are used to determine whether it meets the design requirements. If it does not meet the design requirements, the regional granularity α in the coarse-grained area division algorithm is adjusted and re-divided until a design scheme that meets the pressure drop requirements and has the best heat exchange performance is obtained.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention provides a method for controlling the fluid stroke by adding baffles, thereby ensuring the manufacturing constraints of heat exchanger components.

[0034] When performing baffle search, the present invention utilizes a baffle random search algorithm to enumerate and generate feasible baffle solutions in a backtracking manner, thereby ensuring the feasibility and completeness of the baffle solutions.

[0035] The present invention explores and reveals the law between the baffle addition strategy and the heat exchange performance index, and uses the law to optimize the addition of baffles, thereby improving the overall heat exchange performance of the heat exchanger while meeting the pressure drop requirements.

[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0038] Figure 1 The whole flow chart of the method of an embodiment is as follows;

[0039] Figure 2 This is an example diagram of a 3x3 scale grid baffle solution of an embodiment;

[0040] Figure 3 This is an example diagram of a 5x5 scale grid baffle solution;

[0041] Figure 4 Added example diagram for filling and baffle of TPMS unit structure inside heat exchanger for one embodiment;

[0042] Figure 5 An example diagram of volume mesh division according to an embodiment;

[0043] Figure 6 A flow chart of the internal structure design and optimization algorithm of a heat exchanger according to an embodiment;

[0044] Figure 7 A schematic diagram of case 0 of a run length priority algorithm according to an embodiment;

[0045] Figure 8 A schematic diagram of case 1-case 3 of a run length priority algorithm according to an embodiment;

[0046] Fig. 9 The figure is an example diagram of optimization results of an embodiment. DETAILED DESCRIPTION

[0047] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0048] It should be noted that the following detailed descriptions are all illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0049] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0050] In the absence of conflict, the embodiments in this application and the features in the embodiments may be combined with each other.

[0051] Embodiment 1

[0052] A TPMS micro-element heat exchanger design method based on fluid stroke control includes the following steps:

[0053] (1) Using a random search algorithm, enumerate feasible baffle solutions to form a baffle configuration set;

[0054] (2) Based on the baffle configuration set, generate the corresponding baffle model, fill the TPMS unit structure inside the shell model, and perform volume meshing on the filled model;

[0055] (3) Verify the grid independence of the divided volume grid, perform simulation, calculate the pressure drop, Nusselt number and PEC index, and determine the relationship between the addition of baffles and the heat transfer performance of the heat exchanger based on the indexes;

[0056] (4) Based on the above rules, the baffle configuration set is optimized at two scales, namely, stroke length priority and coarse-grained area division, until the optimal solution is obtained.

[0057] Next, each step is explained in detail:

[0058] Step (1) mainly includes the following steps:

[0059] Step (1-1): Baffle search strategy. In order to study the relationship between baffle addition strategy and heat transfer performance index, the baffle scheme needs to cover the entire design space as comprehensively as possible. At the same time, the scheme needs to satisfy (a) traverse all filling units and (b) all filling units are interconnected to ensure the feasibility of the scheme.

[0060] Therefore, this embodiment uses a random search algorithm to enumerate feasible baffle solutions in a backtracking manner, and abstracts the heat exchanger model into a two-dimensional regular grid G. The scale of G is determined by the period of the TPMS and the size of the heat exchanger, thereby ensuring that each grid point fills a complete TPMS unit cell structure, and baffles are added at the junction of adjacent grid points to control the flow.

[0061] Step (1-2): Initialize the random search algorithm. There are multiple situations in which each filling unit is connected to the neighboring units in the four directions. According to the connected neighboring positions, the four-directional baffle configuration can be determined for the filling unit. All structures are added to the structure table set T{t 1 ,t 2 ,t 3 ,…,t n}, determine the export Inlet structure t inlet And add it to set Q.

[0062] Step (1-3): Breadth-first search (BFS) and backtracking. Take element S from Q i Perform BFS search based on the current S i The structure of i , determine the connected neighborhood unit S i+1 , randomly determine a structure t for it i+1 And add it to the queue Q until all connected neighborhoods are traversed. If the solution is found to be infeasible during the search process, a backtracking operation is performed to return to the previously recorded state, which is S trace Determine an untraversed structure and continue to execute until the constraints are met and the end is at the exit position, returning the baffle set Baffle {b 1 ,b 2 ,b 3 ,…,b n}.

[0063] Simulation example design. Based on the baffle random search algorithm, the initial simulation example is designed. Under the same entrance and exit conditions, this embodiment designs multiple groups of baffle configurations with different shortest strokes on 3x3 and 5x5 scale grids. For the 3x3 scale grid, there are four situations with the shortest stroke length of 3, 5, 7, and 9, and a total of 14 groups of baffle addition schemes are generated. For the complex situation of 5x5 scale, four shortest stroke lengths of 5, 13, 17, and 25 are selected, and a total of 10 groups of baffle addition schemes are generated, as shown in the figure. Figure 2 As shown, this is an example of a 3x3 scale grid baffle solution. Figure 3 This is an example of a 5x5 scale grid baffle solution. The thin blue line in the figure is the fluid stroke, and the thick green line is the baffle.

[0064] The step (2) mainly comprises the following steps:

[0065] Step (2-1): Generate the surface mesh model of the heat exchanger. Surface mesh generation is the initial step in generating the heat exchange mesh model. According to the position of each baffle in each baffle configuration set, the baffle model M1 is generated through Boolean operation and translation. Then, the TPMS unit structure inside the shell model is filled. The TPMS structure is filled inside the abstract shell model. In this embodiment, the Gyroid type TPMS structure is used to fill the internal heat exchange unit of the mesh. Its approximate mathematical expression is as follows:

[0066] φ(r)=sin(X)cos(Y)+sin(Z)cos(X)+sin(Y)cos(Z)=C

[0067] The three-dimensional shell coordinates are discretized into multiple coordinate points according to the set spacing d, and the function value of each point is calculated according to the specified period, thickness, offset and other parameters to generate a signed distance field. The MarchingCube algorithm is executed on the signed distance field to obtain the surface mesh M2 of the model. Finally, the baffle is added, and the surface mesh M1 and M2 are Boolean subtracted. M2 minus M1 to obtain the model M, which is the model after the TPMS structure is filled and the baffle is added, as shown in Figure 4 shown.

[0068] Step (2-2): Body meshing of heat exchanger. Body mesh is used to discretize continuous physical space so that partial differential equations in continuous space can be solved by numerical methods. Converting the surface mesh of the model into a reliable and effective body mesh is the basis for numerical simulation. After obtaining the surface mesh model M, this embodiment uses a combination of tetrahedral mesh and six-layer boundary layer in Ansys ICEM to generate body mesh, and body meshes the generated example surface mesh model.

[0069] Specifically, in this embodiment, six boundary layers with a growth rate of 1.2 and an initial height of 3x10 -5 Meters are used to capture more detailed flow characteristics. The size is set to 1.6x10 at the TPMS heat exchange surface. -3 The tetrahedral mesh is used to accelerate the calculation and generate Figure 5 The volume mesh V is shown.

[0070] The step (3) mainly comprises the following steps:

[0071] Step (3-1): Validity verification. The quality of the volume mesh directly affects the reliability of the simulation. In order to ensure the validity of the volume simulation, this embodiment performs mesh independence verification and convergence analysis on the generated volume mesh.

[0072] The number of grids used was 1.3×10 7 , 2×10 7 and 3.2×10 7 The grid independence of the model was verified and the pressure drop, inlet and outlet temperature difference and Nusselt number (Nu) were compared under the same conditions.

[0073] In this embodiment, the error of pressure drop and temperature difference is within 1%, and the error of Nusselt number is within 5%, both of which are within the acceptable range, ensuring that the volume meshing is fine enough. In the convergence analysis, the simulation reaches the convergence state after 12,000 time steps, ensuring that the simulation results are accurate and effective.

[0074] Step (3-2): Simulation analysis. Use Ansys CFX software to perform CFD simulation on the heat exchanger. The simulation boundary conditions are set as follows: inlet flow rate 0.2m / s, inlet temperature 350K, outlet pressure 101325Pa, TPMS wall temperature 300K, medium is water. Obtain indicators such as outlet temperature, heat transfer, flow rate, inlet and outlet pressures, turbulent kinetic energy, and calculate pressure drop, Nusselt number, PEC (Performance Evaluation Criteria, PEC), etc. Fig. 9 As shown, the analysis starts with these three indicators.

[0075] Step (3-3): The law between the baffle addition strategy and the heat transfer performance index. The analysis of the above indicators revealed the law between the baffle addition strategy and the heat transfer performance of the heat exchanger: (1) Reasonable addition of baffles can improve the overall heat transfer performance: by adding baffles, the length of the stroke can be changed and the flow distribution can be changed, so that the heat exchange unit can be more fully utilized; (2) The longer the stroke, the higher the Nusselt number and PEC, but the pressure drop also increases: the longer the stroke, the more uniform the flow distribution on each path, and the more each unit can be fully utilized. However, as the flow path becomes longer, the pressure drop also increases. The correlation with the stroke length is the strongest for the Nusselt number, followed by the pressure drop, and the weakest for the PEC. (3) For the same length of stroke, the later the baffle affects the flow, the higher the PEC: the earlier the impact on the flow is applied, the greater the loss of kinetic energy, the lower the overall average flow rate, and thus the lower the PEC. The later the impact on the flow, the higher the PEC.

[0076] The step (4) mainly comprises the following steps:

[0077] Step (4-1): Optimization of baffle addition strategy. The balance between pressure drop and heat transfer efficiency is a key issue. The two are usually in a contradictory relationship. Improving heat transfer efficiency often leads to a large pressure drop loss, which may not meet the design requirements. Based on the results of simulation analysis, this embodiment proposes a dual-scale design and optimization method based on coarse-grained area division with stroke length priority, which is divided into two aspects: reducing pressure drop and pursuing the highest heat transfer efficiency. The process is as follows: Figure 6 shown.

[0078] Step (4-2): Coarse-grained region division. Divide the abstracted grid points into several larger regions, establish a mapping relationship, and form a coarse-grained regular grid with reduced scale, so that the fluid travel length is reduced, thereby reducing the pressure drop. First, the ratios of the length and width dimensions of the two-dimensional regular grid after division to the original grid scale n and m are X and Y, respectively, where n*X∈integer, m*Y∈integer, and α(X, Y) is defined as the region division granularity. Based on the region division granularity α and the scale n*m ​​of the graph G, the region is divided on the grid G ​​to obtain a new N*M (N<=n, M<=m) coarse-grained grid G. α , record the mapping relationship f during partitioning.

[0079] Step (4-3): Add baffles with priority on stroke length. As the fluid stroke increases, the heat exchange efficiency PEC increases. Based on the greedy idea, in order to pursue the highest PEC value, it is necessary to design an algorithm with the longest stroke length. Inspired by the Zigzag path, a baffle with priority on stroke length is generated through a divide-and-conquer strategy. α .

[0080] For the design requirement that the entrance and exit are located at any two corners of a regular grid, the idea of ​​scanning lines is used to generate alternating paths from the exit to the entrance. After touching the boundary of graph G, the direction of travel is reversed or changed vertically until the exit is reached, such as Figure 7 As shown, after the end, the baffle configuration is generated according to the path, and this case is named case0.

[0081] For the design requirement that the entrance and exit are located at any boundary position of the regular grid, the divide-and-conquer idea is used to divide the sub-areas and decompose them into the design requirement that the entrance and exit are located at any two corners of the grid. Specifically, according to the relative position of the entrance and exit, there are three cases: opposite side case 1, adjacent side case 2, and same side case 3. Figure 8 As shown. Next, these three categories are divided into sub-areas. Figure 8 As shown in the dividing line, case 1 on the opposite side of the entrance and exit can be decomposed into four case 0s; case 2 on the adjacent side can be decomposed into case 0 and one case 1 on the opposite side; case 3 on the same side can be decomposed into two case 2s on the adjacent side.

[0082] Step (4-4): Region mapping. Map f according to the region division, and map Baffle α By the coarse-grained region G α Reverse mapping to the actual grid G, we get the baffle set Baffle{b1,b2,b3,…,bn}

[0083] Step (4-5): Iterative optimization and verification. The surface mesh and volume mesh of the baffle obtained by the optimized baffle adding algorithm are generated for simulation analysis. After each optimization, it is judged whether it meets the design requirements based on the pressure drop and PEC value. If it does not meet the design requirements, the regional granularity α in the coarse-grained regional division algorithm is adjusted and re-divided until a design solution that meets the pressure drop requirements and has the best heat transfer performance is obtained.

[0084] The simulation verification of the optimization algorithm under four different entrance and exit conditions is as follows Figure 8 As shown in the figure, each row shows the results of different coarse grid divisions under different inlet and outlet conditions. The first column is the baseline case without baffles, the fourth column is the case with the longest stroke but the highest pressure drop, and the middle two columns show the different times of the baffles affecting the flow under coarse grid division. The second column has an early impact and the third column has a late impact. When the pressure drop is close, the PEC of the third column is significantly greater than that of the second column. Therefore, it can be seen from the verification experiment that (1) it conforms to the law between heat transfer indicators and baffles; (2) through the optimized baffle addition strategy, a heat exchanger with higher overall heat transfer performance can be designed while meeting the pressure drop constraint.

[0085] The design and optimization algorithm of the internal structure of the heat exchanger in step (4) runs on a two-dimensional regular grid of n*m. In order to generalize the design space from the regular grid to general heat exchange components, the present invention can also be mapped by a spatial hexahedral decomposition method to make it suitable for the design of heat exchangers of any shape, thereby enhancing universality.

[0086] After mapping the special-shaped heat exchange component to the grid, the design and optimization of the internal structure of the heat exchanger in step (4) are performed, and the added baffle is appropriately deformed according to the shape of the heat exchange component to obtain a design scheme with higher heat exchange performance under the premise of satisfying the pressure drop constraint.

[0087] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0088] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0089] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0090] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0091] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made by those skilled in the art within the spirit and principle of the present invention without creative labor shall be included in the protection scope of the present invention.

Claims

1. A TPMS micro-element heat exchanger design method based on fluid stroke control, characterized in that: The following steps are involved: Using random search algorithm, feasible baffle solutions are enumerated to form a baffle configuration set; Based on the baffle configuration set, the corresponding baffle model is generated, and the TPMS unit structure inside the shell model is filled, and the filled model is meshed; Verify the mesh independence of the divided volume mesh, perform simulation, calculate the pressure drop, Nusselt number and PEC index, and determine the relationship between the addition of baffles and the heat transfer performance of the heat exchanger based on the indexes; Based on the above rules, the baffle configuration set is optimized at two scales, namely, stroke length priority and coarse-grained area division, until the optimal solution is obtained.

2. A TPMS micro-element heat exchanger design method based on fluid stroke control as claimed in claim 1, characterized in that: The feasible baffle solution needs to cover the entire design space as comprehensively as possible, while satisfying the requirements of traversing all filling units and that all filling units are interconnected.

3. A TPMS micro-element heat exchanger design method based on fluid stroke control as claimed in claim 1, characterized in that: Using the random search algorithm, the process of enumerating feasible baffle solutions includes: abstracting the heat exchanger model into a two-dimensional regular grid G, and adding baffles at the junction of adjacent grid points to control the flow; Determine the 4-directional baffle configuration for the filling unit based on the connected neighborhood position, and add all structures to the structure table set T{t1,t2,t3,…,t n }, determine the export Inlet structure t inlet And join the set Q; Take element S from set Q i Perform BFS search based on the current S i The structure of i , determine the connected neighborhood unit S i+1 , randomly determine a structure t for it i+1 And add it to the queue Q until all connected neighborhoods are traversed.

4. A TPMS micro-element heat exchanger design method based on fluid stroke control as claimed in claim 3, characterized in that: The scale of the two-dimensional regular grid G ​​is determined by the period of the TPMS and the size of the heat exchanger to ensure that each grid point fills a complete TPMS unit cell structure.

5. A TPMS micro-element heat exchanger design method based on fluid stroke control as claimed in claim 3, characterized in that: When performing a BFS search, if the solution is found to be infeasible during the search process, a backtracking operation is performed, and the search returns to the previously recorded state. An untraversed structure is determined for the current neighborhood unit and the search continues until the constraints are met and the search ends at the exit position, forming a baffle configuration set.

6. A TPMS micro-element heat exchanger design method based on fluid stroke control as claimed in claim 1, characterized in that: According to the position of each baffle in the baffle configuration set, the baffle model is generated through Boolean operation and translation.

7. A TPMS micro-element heat exchanger design method based on fluid stroke control as claimed in claim 1, characterized in that: The process of filling the TPMS unit structure inside the shell model includes filling the internal heat exchange unit of the grid with the Gyroid type TPMS structure; The three-dimensional shell coordinates are discretized into multiple coordinate points according to the set spacing d, and the function value of each point is calculated according to the set period, thickness and offset parameters to generate a signed distance field. The Marching Cube algorithm is executed on the obtained signed distance field to obtain the surface mesh M2 of the model; Add a baffle, perform Boolean subtraction on the baffle model M1 and the surface mesh M2, and obtain model M by subtracting M1 from M2. Model M is the model after the TPMS structure is filled and the baffle is added.

8. The TPMS micro-element heat exchanger design method based on fluid stroke control according to claim 1, characterized in that: The process of volume meshing the filled model includes setting six boundary layers near the TPMS heat exchange surface in the surface mesh to capture more detailed flow characteristics; setting a tetrahedral mesh at the TPMS heat exchange surface to accelerate the calculation and generate a volume mesh V.

9. A TPMS micro-element heat exchanger design method based on fluid stroke control as claimed in claim 1, characterized in that: Based on the above rules, the baffle configuration set is optimized with dual scales of stroke length priority and coarse-grained region division until the optimal solution is obtained, which includes: dividing each grid point of the abstracted grid into a number of regions, establishing a mapping relationship, and forming a coarse-grained regular grid, so that the fluid stroke length is reduced, thereby reducing the pressure drop; For the design requirement that the entrance and exit are located at any two corners of a regular grid, the idea of ​​scanning lines is used to generate an alternating path from the exit to the entrance. After touching the boundary of graph G, the direction of travel is reversed or changed vertically until the exit is reached. After the end, the baffle configuration is generated according to the path; For the design requirement that the entrance and exit are located at any boundary position of the regular grid, the divide-and-conquer idea is adopted to divide the sub-areas and decompose them into the design requirement that the entrance and exit are located at any two corners of the grid.

10. A TPMS micro-element heat exchanger design method based on fluid stroke control as claimed in claim 1 or 9, characterized in that: In the dual-scale optimization process of stroke length priority and coarse-grained area division for the baffle configuration set, the surface mesh and volume mesh of the baffle obtained by the optimized baffle addition algorithm are generated for simulation analysis. After each optimization, the pressure drop and PEC value are used to determine whether it meets the design requirements. If it does not meet the design requirements, the regional granularity α in the coarse-grained area division algorithm is adjusted and re-divided until a design scheme that meets the pressure drop requirements and has the best heat exchange performance is obtained.

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