Fluid simulation method for semi-welded plate heat exchanger

Abstract

The invention discloses a fluid simulation method for a semi-welded plate heat exchanger, which relates to the technical field of heat exchanger simulation and comprises the following steps: acquiring porous medium parameters of a porous medium model by using a single-side medium three-dimensional model; performing grid division on the single-side medium three-dimensional model to obtain a grid division result of the single-side medium three-dimensional model; according to the porous medium parameters of the porous medium model and the grid division result of the single-side medium three-dimensional model, preliminary flow field trial calculation is carried out based on a k-omega SST turbulence model, and a preliminary flow field trial calculation result is obtained; fitting processing is carried out based on the preliminary flow field trial calculation result, and a semi-welded plate type alternating current device fluid simulation result is obtained. According to the method, single-side overall pressure drop prediction of the semi-welded plate heat exchanger is achieved, on the basis, the turbulence model is used for predicting the flowing condition of media between the plates, the accuracy of heat exchanger flow field calculation is greatly improved, flowing near the wall faces of the plates is closer to the actual state, and the positive effect on prediction of the performance of the heat exchanger is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchanger simulation, and in particular to a fluid simulation method for a semi-welded plate heat exchanger. Background Art

[0002] To improve energy access and living environments for both urban and rural residents, centralized heating is evolving towards using suburban thermal power plants as heat sources, with long-distance pipeline networks providing heat to urban areas. These long-distance pipelines present complex routings, significant elevation changes, and pressure levels that are incompatible with urban networks. This often necessitates the installation of pressure isolation stations, where heat exchangers are a key component. Currently, the maximum design pressure of detachable plate heat exchangers is 4.0 MPa, which cannot meet the design requirements of some pressure isolation stations. Therefore, a high-pressure, semi-welded plate heat exchanger is required.

[0003] However, there are still some technical difficulties in the field of plate heat exchanger fluid simulation. The overall size span of the heat exchanger is large and the structure is complex. There is a lack of experimental data for the design of new heat exchangers. Directly building a three-dimensional solid model of the whole machine faces problems such as complex geometric modeling, a large number of grids, difficulty in improving grid quality, and high computational resource consumption, making it difficult to simulate and predict the overall performance. At the same time, most of the estimates of unilateral pressure drop are based on local structural simulation, ignoring the loss of the medium entering the plate from the corner hole, or testing the performance parameters through experiments, which has the problems of long cycle and high cost. In addition, the porous medium model can greatly simplify the internal details of the channel and use porous medium parameters to describe the flow properties between the plates of the semi-welded plate heat exchanger.

[0004] Therefore, there is an urgent need for a fluid simulation method for a semi-welded plate heat exchanger to address the deficiencies in the existing technology. Summary of the Invention

[0005] The purpose of this invention is to propose a fluid simulation method for semi-welded plate heat exchangers to solve the problem of predicting the pressure drop of a single-sided integral semi-welded plate heat exchanger using a porous medium model. k - oh The SST model is used to calculate and predict the flow of media between the heat exchanger plates.

[0006] To achieve the above object, the present invention provides a fluid simulation method for a semi-welded plate heat exchanger, comprising the following steps: S1. Using a single-side medium three-dimensional model, obtain porous medium parameters of a porous medium model; S2. Meshing the single-sided medium three-dimensional model to obtain a meshing result of the single-sided medium three-dimensional model; S3, based on the porous medium parameters of the porous medium model and the grid division results of the single-side medium three-dimensional model k - ohPerform preliminary flow field calculations using the SST turbulence model to obtain preliminary flow field calculation results; S4. Perform fitting processing based on the preliminary flow field trial calculation results to obtain fluid simulation results of the semi-welded plate exchanger.

[0007] Optionally, S1, using the single-side medium three-dimensional model, obtain porous medium parameters of the porous medium model, including: Obtain the key structural parameters of the corrugated plates through a semi-welded plate heat exchanger; Establishing a parametric three-dimensional model of the corrugated plate based on key structural parameters of the corrugated plate; A single-side medium three-dimensional model is established using the parameterized three-dimensional model of the corrugated plate to obtain porous medium parameters of the porous medium model.

[0008] Optionally, using the parameterized three-dimensional model of the corrugated plate to establish a single-sided medium three-dimensional model, and obtaining porous medium parameters of the porous medium model, includes: Assembling the parameterized three-dimensional model of the corrugated plate to obtain an assembly of the corrugated plate; Obtaining a fluid physics calculation domain based on the assembly of the corrugated sheet and Boolean operations; Performing geometric repair based on the fluid physics calculation domain to construct a single-sided medium three-dimensional model; Performing geometric feature parameter mapping on the single-sided medium three-dimensional model to obtain geometric feature parameters of the single-sided medium three-dimensional model, wherein the geometric feature parameters include corner hole shrinkage ratio, corrugation disturbance angle, equivalent hydraulic diameter and porosity; Obtaining a resistance coefficient of the porous medium model using a preset fitting coefficient according to the geometric characteristic parameters of the single-sided medium three-dimensional model, wherein the resistance coefficient of the porous medium model includes an inertial resistance coefficient and a viscous resistance coefficient of the porous medium model; Establishing a porous medium model using the resistance coefficient of the porous medium model and the porosity; Using the porous medium model and a solid model corresponding to the porous medium model, obtaining a single-side pressure drop error between the porous medium model and the solid model; determining whether a unilateral pressure drop error between the porous medium model and the solid model meets a unilateral pressure drop error threshold; if so, obtaining the porosity, the inertial resistance coefficient, the viscous resistance coefficient, and the equivalent hydraulic diameter as porous medium parameters of the porous medium model; otherwise, adjusting the preset fitting coefficient and returning to executing the first operation; The first operation is to obtain the resistance coefficient of the porous medium model using a preset fitting coefficient according to the geometric characteristic parameters of the single-sided medium three-dimensional model.

[0009] Optionally, S2, meshing the single-sided medium three-dimensional model to obtain a meshing result of the single-sided medium three-dimensional model, includes: Performing geometric preprocessing on the single-sided medium three-dimensional model to obtain a preprocessed single-sided medium three-dimensional model and periodic boundary conditions; Performing polyhedral mesh division on the pre-processed single-sided medium three-dimensional model based on the periodic boundary condition to obtain a mesh division result of the pre-processed single-sided medium three-dimensional model; Quality control is performed based on the preprocessed mesh division result of the single-sided medium three-dimensional model to obtain the mesh division result of the single-sided medium three-dimensional model.

[0010] Optionally, performing quality control based on the preprocessed mesh division result of the single-sided medium three-dimensional model to obtain the mesh division result of the single-sided medium three-dimensional model includes: Obtaining the distortion rate and aspect ratio of the mesh division result by preprocessing the mesh division result of the single-sided medium three-dimensional model; Determining whether the distortion rate of the meshing result meets a preset distortion rate threshold; if so, performing a second operation; otherwise, deleting the meshing result that does not meet the preset distortion rate threshold based on the meshing result of the preprocessed single-sided medium three-dimensional model, and performing the second operation; Among them, the second operation is: determine whether the aspect ratio of the grid division result meets the preset aspect ratio threshold; if so, obtain the grid division result of the pre-processed single-sided medium three-dimensional model as the grid division result of the single-sided medium three-dimensional model; otherwise, delete the grid division result that does not meet the preset aspect ratio threshold according to the grid division result of the pre-processed single-sided medium three-dimensional model, and obtain the grid division result of the single-sided medium three-dimensional model.

[0011] Optionally, S3, based on the porous medium parameters of the porous medium model and the meshing result of the single-side medium three-dimensional model k - oh The SST turbulence model performs preliminary flow field calculations. Before obtaining the preliminary flow field calculation results, the following steps are also included: Set the boundary condition of the single-side inlet; Based on the single-sided inlet boundary condition, the Reynolds number is obtained.

[0012] Optionally, S3, based on the porous medium parameters of the porous medium model and the meshing result of the single-side medium three-dimensional model k - oh The SST turbulence model performs preliminary flow field calculations and obtains preliminary flow field calculation results, including: Based on the Reynolds number, obtaining the turbulence intensity in the channel; The turbulence intensity in the channel is used tok - oh Initialize the SST turbulence model and obtain the initialization k - oh SST turbulence model; The porous medium parameters of the porous medium model and the grid division results of the single-side medium three-dimensional model are input into the initialization k - oh The SST turbulence model performs preliminary flow field calculations based on the single-side inlet boundary conditions to obtain preliminary flow field calculation results.

[0013] Optionally, S4, performing fitting processing based on the preliminary flow field trial calculation results to obtain fluid simulation results of the semi-welded plate exchanger, including: Using the preliminary flow field calculation results, obtain pressure drop data of the welded plate heat exchanger; Performing fitting processing on the pressure drop data of the welded plate heat exchanger to obtain a fitting result of the pressure drop data; The fitting results of the pressure drop data are verified to obtain the fluid simulation results of the semi-welded plate exchanger.

[0014] Optionally, verifying the fitting result of the pressure drop data to obtain the fluid simulation result of the semi-welded plate alternator includes: Obtaining a predicted value of the fitting result through the fitting result of the pressure drop data; performing point-by-point comparison based on the predicted value of the fitting result and the pressure drop data of the welded plate heat exchanger to obtain a comparison error; Determine whether the comparison error meets a preset comparison error value; if so, obtain a fluid simulation result of the semi-welded plate alternator according to the fitting result of the pressure drop data; otherwise, return to perform the third operation; The third operation is to perform fitting processing on the pressure drop data of the welded plate heat exchanger to obtain a fitting result of the pressure drop data.

[0015] Compared with the closest prior art, the present invention has the following beneficial effects: The present invention realizes the prediction of the overall pressure drop on one side of the semi-welded plate heat exchanger, and on this basis, uses k - oh The SST turbulence model predicts the flow of media between plates, greatly improving the accuracy of heat exchanger flow field calculations and making the flow near the plate wall closer to the actual state, which has a positive effect on predicting heat exchanger performance.

[0016] The present invention is based on k - ohThe SST turbulence model can more accurately simulate the flow state near the wall of the plate, increasing the simulation accuracy of fluid analysis; the present invention can effectively shorten the product design cycle and the cost of new product development through periodic boundary conditions; the present invention uses a porous medium model to predict the pressure drop of the entire semi-welded plate heat exchanger, solving the existing problem of being unable to predict the overall pressure drop on one side. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 This is a flow chart of a fluid simulation method for a semi-welded plate heat exchanger according to an embodiment of the present invention. DETAILED DESCRIPTION

[0019] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] The terms used in the embodiments of the present invention are only used to explain the specific embodiments of the present invention and are not intended to limit the present invention.

[0021] like Figure 1 As shown, an embodiment of the present invention provides a fluid simulation method for a semi-welded plate heat exchanger, comprising: S1. Using a single-side medium three-dimensional model, obtain porous medium parameters of a porous medium model; The single-side medium 3D model is a 3D spatial model of a single fluid channel (such as only the cold side or hot side medium) in a semi-welded plate heat exchanger. It is used to simulate the flow process of the medium on this side from the inlet to the outlet. The porous medium model simplifies the inter-plate flow channel of the semi-welded plate heat exchanger with a complex internal structure into a virtual medium full of pores. Using the single-side medium 3D model, relevant parameters that characterize the characteristics of porous media, such as porosity, are obtained. e , inertial drag coefficient C 2. Viscous drag coefficient 1 / α , equivalent hydraulic diameter D hThese parameters are the important basis for subsequent simulation calculations and can reflect the influence of porous media on fluid flow and heat transfer.

[0022] S2. Meshing the single-sided medium three-dimensional model to obtain a meshing result of the single-sided medium three-dimensional model; Meshing was performed on the single-sided medium 3D model to obtain the corresponding meshing results. Due to the unique plate structure and small plate spacing of semi-welded plate heat exchangers, which contain numerous small gaps, slits, sharp corners, and other irregularly shaped areas, a polyhedral mesh, combined with localized encryption and automatic node movement, was used to reduce meshing time and control the number of meshes while ensuring mesh quality and meeting engineering application requirements.

[0023] S3, based on the porous medium parameters of the porous medium model and the grid division results of the single-side medium three-dimensional model k - oh Perform preliminary flow field calculations using the SST turbulence model to obtain preliminary flow field calculation results; According to the obtained porous media parameters and mesh division results, based on k - oh The SST turbulence model is used to carry out preliminary flow field calculations. The model can accurately simulate the flow state near the wall and solve the turbulent energy. k , turbulent dissipation rate oh , turbulent viscosity m t Etc., to obtain the flow field calculation results such as velocity field and pressure field, and provide data support for subsequent fitting.

[0024] S4. Perform fitting processing based on the preliminary flow field trial calculation results to obtain fluid simulation results of the semi-welded plate exchanger; The preliminary flow field calculation results were fitted, and by fitting the relationship between the pressure drop and flow velocity on the hot and cold sides of the porous media model, the fluid simulation results of the semi-welded plate heat exchanger were finally obtained, including the prediction of the overall pressure drop on one side and the flow field distribution characteristics. This can provide an in-depth understanding of the fluid flow and pressure drop characteristics in the heat exchanger, which is convenient for guiding the performance evaluation and design optimization of the heat exchanger.

[0025] In summary, steps S1 to S4 obtain the porous medium parameters of the porous medium model through the unilateral medium three-dimensional model, then mesh the unilateral medium three-dimensional model, and then use the obtained parameters and meshing results to k - ohInitial flow field calculations were performed using the SST turbulence model, and finally, fitting processing was performed based on the results to obtain fluid simulation results for a semi-welded plate commutator. This series of operations accurately simulated the fluid flow conditions within the semi-welded plate commutator, effectively improving the accuracy and reliability of the fluid simulation. This provided scientific and accurate data support for optimizing the structural design and performance parameters of the semi-welded plate commutator, reducing R&D costs and cycles.

[0026] As a possible implementation, in the above embodiment, step S1 may specifically include the following steps: S1-1. Obtain key structural parameters of corrugated plates using a semi-welded plate heat exchanger. Extract the key structural parameters of the corrugated plate from the design drawings or physical objects of the semi-welded plate heat exchanger, such as plate length L 、Board width W , plate thickness d , board spacing d , corrugation angle i , wave height h 、French Festival t , corrugation inclination α , Corner hole diameter f The actual object is precisely measured using a three-dimensional coordinate measuring machine or laser scanning technology, ensuring parameter errors of less than 0.1mm. For design drawings, parametric definitions are directly read through CAD software to establish a parameter database. This step provides an accurate data foundation for subsequent modeling, avoiding simulation errors caused by parameter deviations and ensuring geometric consistency between the model and the actual product.

[0027] S1-2. Establishing a parametric three-dimensional model of the corrugated plate based on key structural parameters of the corrugated plate; Using parametric CAD software such as SolidWorks, the key structural parameters of the corrugated sheet obtained above are set as variables. A dimensionally driven mathematical expression (such as a sine function) for the corrugated surface is generated, creating a fully parametric 3D model. Parameter associations are established to ensure that the model automatically updates when any parameter is modified. The meshing of the corrugations of adjacent sheets is also checked, eliminating interference areas (e.g., peak-to-valley misalignment ≤ 0.05mm). This model allows for the one-click generation of different sheet shapes, achieving design standardization and automation, and shortening model update time compared to traditional methods.

[0028] S1-3, using the parameterized three-dimensional model of the corrugated plate to establish a single-sided medium three-dimensional model, and obtain porous medium parameters of the porous medium model; Using a parametric 3D model of the corrugated plate, a single-sided 3D media model was constructed. Porosity, resistance coefficient, and other porous media parameters were derived using volumetric statistics and dimensional analysis, enabling precise acquisition of these parameters. This operation, through parametric modeling and geometric calculations, ensures geometric consistency between the porous media model and the actual flow path, minimizing errors in porosity calculations and providing reliable physical parameters for subsequent flow field simulations, effectively improving the consistency between simulation results and actual operating conditions.

[0029] In summary, steps S1-1 through S1-3 obtain the key structural parameters of the corrugated plates from a semi-welded plate heat exchanger. Based on these parameters, a parametric 3D model of the corrugated plates is established using software such as SolidWorks, enabling rapid parameter-driven model generation and modification. This 3D model is then used as a foundation to construct a single-sided medium 3D model by assembling adjacent plates and performing Boolean operations. Data such as the fluid domain volume and equivalent hydraulic diameter are then extracted from this model to calculate the porous medium parameters. This process enhances design flexibility and modeling efficiency through parametric modeling. It can rapidly generate different plate types and accurately extract porous medium parameters, enabling the porous medium model to effectively reflect the flow characteristics of the actual flow channel. Compared to physical flow channel simulation, this reduces pressure drop prediction errors, reduces the number of meshes, and significantly improves computational efficiency, providing an accurate and efficient foundation for fluid simulation and optimization design of semi-welded plate heat exchangers.

[0030] As a possible implementation, in the above embodiment, step S1-3 may specifically include the following steps: S1-3-1. Assembling the parameterized three-dimensional model of the corrugated plate to obtain an assembly of the corrugated plate; For the parametric 3D model of the corrugated plate, two adjacent plates are simulated at the actual spacing to obtain the assembly state, ensuring that the corrugations of the adjacent plates mesh without interference (for example, the misalignment of the corrugation peaks and valleys is ≤0.1mm). The corrugated plate assembly refers to the combination of two corrugated plates precisely aligned and fixed at the designed spacing (for example, 2-3mm). This simulates the assembly state of the plates in the actual heat exchanger and ensures that the fluid domain geometry is consistent with the actual flow path. This is the basis for extracting the single-sided medium model.

[0031] S1-3-2. Obtaining a fluid physics calculation domain based on the assembly of the corrugated plate sheets using Boolean operations; Using Boolean operations (subtraction), a single-sided medium space is extracted from the assembly. Inlet corner holes, outlet surfaces, and sealing boundaries are added. All surfaces are stitched together to create a fluid physics computational domain. This ensures that the fluid domain topology matches the actual flow path, minimizing manual modeling errors. In this example, the fluid physics computational domain is formed by stacking two corrugated plates, creating a complex three-dimensional flow path.

[0032] S1-3-3. Perform geometric repair based on the fluid physics calculation domain to construct a single-sided medium three-dimensional model; Curvature analysis is used to mark geometric defects such as corrugation tips and slits, and these defects are monitored using CAD and other software. Geometric defects such as tiny gaps and overlapping surfaces within the fluid physics calculation domain are repaired to ensure a smooth surface for the corrugated plate and avoid tiny gaps or overlapping surfaces. Different boundary condition labels are assigned to inlet corner holes, outlet surfaces, and wall surfaces to facilitate subsequent computational fluid dynamics (CFD) settings and ensure the reliability of flow field calculations.

[0033] S1-3-4. Performing geometric feature parameter mapping on the single-sided medium three-dimensional model to obtain geometric feature parameters of the single-sided medium three-dimensional model, wherein the geometric feature parameters include corner hole shrinkage ratio, corrugation disturbance angle, equivalent hydraulic diameter, and porosity; First, when performing parameterized mapping of geometric features on the 3D model of the single-sided medium, the key structural parameters of the corrugated plate are firstly determined by the corner hole diameter. f Distance from board d , calculate the corner hole shrinkage ratio β ,Right now β = f / d , to quantify the degree of flow contraction at the inlet section; secondly, based on the corrugation inclination α Extract the ripple disturbance angle Δ i , that is, Δ i =2 a , used to evaluate the disturbance intensity of the ripple on the fluid; again, select the flow channel section, through the cross-sectional area A Wet perimeter P Calculate the equivalent hydraulic diameter D h ,Right now D h =4 A / P , providing a basis for Reynolds number calculation; finally, the volume statistics function of the software is used to obtain the volume of the fluid domain V f and the plate solid volume V s , calculate the porosity, that is e = V f / ( V f + V sThis process achieves a precise conversion from solid geometry to physical parameters, reducing the deviation between actual measurements of parameters such as the angular hole shrinkage ratio and the ripple disturbance angle, as well as the calculation error of the equivalent hydraulic diameter. This lays a high-precision data foundation for the subsequent derivation of the resistance coefficient of the porous media model, effectively ensuring the accuracy and reliability of the flow field simulation.

[0034] S1-3-5. Obtaining a resistance coefficient of the porous medium model using a preset fitting coefficient based on the geometric characteristic parameters of the single-sided medium three-dimensional model, wherein the resistance coefficient of the porous medium model includes an inertial resistance coefficient and a viscous resistance coefficient of the porous medium model; Based on the geometric characteristic parameters such as corner hole shrinkage ratio, corrugation angle, equivalent hydraulic diameter, porosity, etc. extracted from the unilateral medium three-dimensional model, the inertial resistance coefficient is obtained by least squares fitting through dimensional analysis and CFD pre-calculation data. C 2, that is C 2= k 1. i · β + k 2; At the same time, the viscous drag coefficient 1 / is derived based on Darcy's law α Distance from board d , porosity e The relationship is 1 / α = k 3. d -1 · e -2 , we get the viscous drag coefficient 1 / α .in, k 1. k 2 is the preset fitting coefficient, k 3 is the material coefficient (stainless steel corrugated plate k 3=3.6×10 -3 Compared with traditional local simulation, this method improves the efficiency of parameter extraction, reduces the number of grids in porous media model calculations, and shortens the time required for a single simulation. It provides high-precision and high-efficiency parameter support for the prediction of the overall pressure drop on one side of a semi-welded plate heat exchanger.

[0035] S1-3-6. Establishing a porous medium model using the resistance coefficient and the porosity of the porous medium model; Based on the obtained inertial drag coefficient C 2、 Viscous drag coefficient 1 / α and porosity e, and substitute it into the Darcy-Forchheimer equation to construct a porous media model. This model reduces the number of grids and shortens the calculation time by simplifying the complex three-dimensional corrugated flow channel into an abstract porous media model. It effectively solves the problems of complex overall modeling and high computing resource consumption of semi-welded plate heat exchangers, and provides an engineering practical tool for rapid performance evaluation and plate type optimization of heat exchangers.

[0036] S1-3-7. Using the porous medium model and the solid model corresponding to the porous medium model, obtain a unilateral pressure drop error between the porous medium model and the solid model; The porous media model and the corresponding solid model were imported into simulation software such as Fluent. Flow field calculations were performed under identical boundary conditions (e.g., inlet velocity of 1.5 m / s and outlet pressure of 0 Pa), and the unilateral pressure drop error was calculated. The solid model used a 300,000-cell polyhedral mesh with local refinement, while the porous media model employed simplified calculations based on the drag coefficient formula. This process quantifies the accuracy of the porous media model, saving verification costs compared to traditional physical testing. Furthermore, an error feedback mechanism ensures that the flow characteristics of the porous media model match those of the solid channel.

[0037] S1-3-8. Determine whether the unilateral pressure drop error between the porous medium model and the solid model meets the unilateral pressure drop error threshold. If so, obtain the porosity, the inertial resistance coefficient, the viscous resistance coefficient, and the equivalent hydraulic diameter as porous medium parameters of the porous medium model. Otherwise, adjust the preset fitting coefficient and return to S1-3-5. The single-sided pressure drop error between the porous media model and the solid model is compared with a preset single-sided pressure drop error threshold (e.g., 8%). If the error is within the threshold (≤8%), the initial porous media parameters of the current porous media model (including porosity, inertial resistance coefficient, viscous resistance coefficient, equivalent hydraulic diameter, etc.) are deemed to meet the accuracy requirements and are directly used as the final porous media parameters. If the error exceeds the threshold (>8%), the preset fitting coefficients are adjusted according to the rules (e.g., the fitting coefficient is adjusted to the original value × (1 + error / 10)). The geometric characteristic parameters (such as corrugation angle, corner hole shrinkage ratio, etc.) based on the single-sided medium 3D model and the adjusted fitting coefficients are returned to re-derive the resistance coefficient of the porous media model. This process, through error judgment and iterative correction, can achieve automatic optimization of porous media model parameters, ensure that simulation accuracy meets engineering requirements, improve design efficiency, and reduce R&D costs.

[0038] In summary, steps S1-3-1 to S1-3-8 revolve around the acquisition of porous media model parameters. First, the parametric three-dimensional model of the corrugated plate is assembled to obtain an assembly. The fluid physics calculation domain is obtained through Boolean operations. A single-sided medium three-dimensional model is then constructed through geometric repair. The geometric features are then parametrically mapped. The resistance coefficient of the porous media model is obtained based on the obtained parameters and preset fitting coefficients. After the model is established, the single-sided pressure drop error is compared with the solid model. The parameters are then determined or adjusted based on whether the error meets the threshold. This solution can accurately construct a porous media model that meets actual working conditions, effectively improving the accuracy of porous media parameter acquisition. This provides a more reliable data foundation for subsequent semi-welded plate exchanger fluid simulations based on these parameters, thereby enhancing the guiding value of the simulation results for product design optimization and performance evaluation.

[0039] As a possible implementation, in the above embodiment, step S2 may specifically include the following steps: S2-1. Performing geometric preprocessing on the single-sided medium three-dimensional model to obtain a preprocessed single-sided medium three-dimensional model and periodic boundary conditions; When performing geometric preprocessing on a single-sided medium 3D model, the team first eliminates geometric defects such as tiny gaps and overlapping surfaces, rounds the sharp corners of the corrugated structure, and removes minor features that do not affect the mainstream flow field to simplify the flow channel topology, obtaining the preprocessed model. Secondly, the boundary regions such as the inlet, outlet, and wall are clearly demarcated, and high-gradient areas with complex flow states are marked. Finally, periodic cells containing complete wave-troughs are extracted from the preprocessed single-sided medium 3D model. Periodic boundary conditions are set on both sides of the cells to ensure that the flow field characteristics are periodically repeated at the boundaries. This process effectively improves the model's geometric quality, reduces invalid computational areas, provides a regularized geometric foundation for subsequent meshing, and significantly reduces computational scale through periodic modeling.

[0040] S2-2, performing polyhedral meshing on the pre-processed single-sided medium three-dimensional model based on the periodic boundary condition, and obtaining a meshing result of the pre-processed single-sided medium three-dimensional model; The unique structure of the semi-welded plate heat exchanger results in very small plate spacing, which results in many small gaps, slits, sharp corners and other irregular areas when meshing. In order to reduce meshing time and control the number of meshes while ensuring mesh quality and meeting engineering applications, a polyhedron mesh is used. Based on periodic boundary conditions, a hybrid meshing strategy is applied to the preprocessed model: a polyhedral mesh is used for the main flow channel to accommodate the complex geometry, a multi-layer prismatic boundary layer is generated on the plate wall to accurately resolve the near-wall flow, and local mesh refinement is performed in key areas such as the inlet contraction and corrugation turning points. This meshing approach leverages the geometric adaptability of the polyhedral mesh to reduce the number of cells, while ensuring computational accuracy in key areas through local refinement. This balances computational efficiency and accuracy while ensuring that the mesh meets the requirements for solving the turbulence model.

[0041] S2-3. Performing quality control based on the pre-processed mesh division result of the single-sided medium three-dimensional model to obtain a mesh division result of the single-sided medium three-dimensional model; The meshing results are quality-controlled. The quality-controlled mesh can accurately capture the velocity gradient and flow separation phenomena in the flow field, avoiding calculation errors or solution failures caused by mesh defects. It provides a reliable mesh foundation for subsequent flow field calculations and ensures that the simulation results can truly reflect the actual flow state in the heat exchanger.

[0042] In summary, steps S2-1 to S2-3 first perform geometric preprocessing on the single-sided medium 3D model. This not only yields a preprocessed single-sided medium 3D model but also determines periodic boundary conditions, laying the foundation for subsequent calculations. Polyhedral meshing is then applied to the preprocessed model based on the periodic boundary conditions to better fit the model's complex geometry and obtain preliminary meshing results. Finally, quality control optimizes these preliminary results to obtain the final meshing results for the single-sided medium 3D model. This approach effectively improves the accuracy and quality of meshing, accurately capturing the model's geometric features and flow characteristics, reducing computational errors, and enhancing the accuracy and stability of flow field calculations and fluid simulations based on this meshing. This provides a reliable mesh foundation for performance analysis and optimized design of semi-welded plate-type AC units.

[0043] As a possible implementation, in the above embodiment, step S2-3 may specifically include the following steps: S2-3-1. Obtaining the distortion rate and aspect ratio of the meshing result by pre-processing the meshing result of the single-sided medium three-dimensional model; S2-3-2. Determine whether the distortion rate of the meshing result meets a preset distortion rate threshold. If so, perform the second operation. Otherwise, delete the meshing result that does not meet the preset distortion rate threshold based on the meshing result of the pre-processed single-sided medium three-dimensional model, and perform S2-3-3. S2-3-3. Determine whether the aspect ratio of the grid division result meets the preset aspect ratio threshold. If so, obtain the grid division result of the pre-processed single-sided medium three-dimensional model as the grid division result of the single-sided medium three-dimensional model. Otherwise, delete the grid division results that do not meet the preset aspect ratio threshold according to the grid division result of the pre-processed single-sided medium three-dimensional model, and obtain the grid division result of the single-sided medium three-dimensional model.

[0044] In summary, steps S2-3-1 through S2-3-3 obtain the distortion rate and aspect ratio of the preprocessed single-sided medium three-dimensional model meshing result, first determining whether the distortion rate meets the preset distortion rate threshold. If not, the corresponding mesh is deleted, and then determining whether the aspect ratio meets the preset aspect ratio threshold (≤15). If it does, the mesh is determined as the final result. This process improves the mesh quality compliance rate, reduces near-wall flow simulation errors, and ensures the stability and accuracy of the flow field calculation. In this embodiment, the preset distortion rate threshold is set to ≤0.9, and the preset aspect ratio threshold is set to ≤15.

[0045] As a possible implementation, in the above embodiment, before executing step S3, the following steps are further included: Set the boundary condition of the single-side inlet; Based on the single-sided inlet boundary condition, the Reynolds number is obtained.

[0046] Before performing preliminary flow field calculations, it is necessary to set the single-side inlet boundary condition according to the calculation sheet of the design working condition. That is, assume that the medium in the corner hole is evenly distributed, calculate the inlet condition of the single-side channel, the outlet is free outflow, and the rest are wall surfaces; then, calculate the Reynolds number based on the single-side inlet boundary condition. Re , the calculation formula is as follows:

[0047] in, r is the fluid density, v is the flow velocity, D is the characteristic size, m is the dynamic viscosity of the fluid.

[0048] In summary, the above process is k - oh The SST turbulence model provides key input parameters. The Reynolds number guides turbulence model selection and parameter initialization, while the inlet conditions directly constrain the flow state in the computational domain. This results in a reduction in pressure drop prediction error, improved accuracy in capturing the turbulent boundary layer, and faster computational convergence. It also ensures that the flow field calculation results are both consistent with physical laws and engineering reliable.

[0049] As a possible implementation, in the above embodiment, step S3 may specifically include the following steps: S3-1. Obtaining turbulence intensity in the channel based on the Reynolds number; By Reynolds number ( Re ) quantifies the ratio of the fluid inertial force to the viscous force, thereby determining the flow state (laminar or turbulent). The turbulence intensity in the channel is further calculated based on the Reynolds number. I ,Right now I =0.16( Re D ) -1 / 8 , which characterizes the severity of fluid pulsation. This process provides a key input for the turbulence model to reflect the actual flow characteristics by correlating the Reynolds number with the turbulence intensity in the channel, enabling the model to accurately capture the turbulent disturbances caused by changes in flow velocity, fluid properties, and channel size between the heat exchanger plates. For example, under high Reynolds number conditions ( Re >10 4 ), which can accurately evaluate the impact of turbulence intensity on flow separation and vortex formation, laying the foundation for subsequent flow field calculations.

[0050] S3-2, using the turbulence intensity in the channel to k - oh Initialize the SST turbulence model and obtain the initialization k - oh SST turbulence model; The calculated turbulence intensity in the channel I , by quantifying the fluid pulsation characteristics to drive the initialization of the core parameters of the k-ω SST turbulence model. Specifically: First, the turbulent kinetic energy ( k ), which characterizes the energy of the fluid turbulence pulsation; then, the turbulence scale l and the model intrinsic constants C μ = 0.09, solve for the turbulent dissipation rate ( oh ), which reflects the dissipation rate of turbulent energy; finally, the calculated k and oh The k-ω SST model parameters are initialized as initial conditions. This process initializes the model using turbulence intensity, improving the k-ω SST model's accuracy in simulating adverse pressure gradient flows (such as flow separation and reattachment) along heat exchanger plate corrugations. Compared to the standard k-ε model, it can more accurately predict the distribution of turbulence intensity in complex areas such as narrow slits and sharp corners, avoiding flow field calculation distortion caused by deviations in model parameter settings and providing reliable turbulence characteristic input for subsequent flow field calculations.

[0051] S3-3, input the porous medium parameters of the porous medium model and the grid division result of the single-side medium three-dimensional model into the initialization k - oh SST turbulence model, based on the single-side inlet boundary condition, performs preliminary flow field trial calculation to obtain preliminary flow field trial calculation results; Import the porous media parameters and a high-quality mesh (the meshing result of a single-sided medium 3D model) into the initialized model. Combined with the single-sided inlet boundary conditions, a preliminary flow field calculation is performed to obtain the velocity field, pressure field, and turbulence parameters. This coupling of the porous media parameters with the turbulence model directly calculates the resistance effect of fluid passing through the plate structure, minimizing the deviation between the pressure drop calculation and actual operating conditions. The synergy between the high-quality mesh and the model ensures the accuracy of near-wall turbulence analysis and improves the convergence rate of the calculation, providing reliable flow field data support for subsequent implementation and enabling efficient transition from numerical simulation to engineering application.

[0052] k - oh The SST turbulence model is defined as follows: Turbulent energy k equation:

[0053] Turbulent dissipation rate oh equation:

[0054] Turbulent viscosity m t equation:

[0055] in, k is the turbulent kinetic energy, r is the fluid density, t For time, u i For fluid i The velocity component in the direction, x i for i Direction space coordinates, t ij is the stress tensor, u j For fluid j The velocity component in the direction, β * is the model constant, and this embodiment sets β * =0.09, oh is the turbulent dissipation rate, m is the fluid dynamic viscosity, s k is the turbulent kinetic energy diffusion coefficient, m t is the turbulent viscosity, cis the model constant, v t is the kinematic viscosity, P is the turbulent kinetic energy generation term, β is the model constant, s ω is the turbulent dissipation rate diffusion coefficient, F 1 is the main mixing function (a function with a value between 0 and 1), s ω2 is the model constant, a * is the model constant, S is the strain rate, F 2 is the secondary mixing function (a function with a value between 0 and 1), a 1 is the model constant.

[0056] In summary, steps S3-1 to S3-3 determine the turbulence intensity in the channel based on the Reynolds number, and use this as a basis for k - oh Initialize the SST turbulence model to get an initialization that is more in line with the actual working conditions k - oh The SST turbulence model is then used. The porous media parameters of the porous media model and the meshing results of the single-sided media 3D model are then input into the model. Preliminary flow field calculations are then performed in conjunction with the single-sided inlet boundary conditions to obtain preliminary flow field calculation results. This process effectively improves the fit between the turbulence model and the actual flow state. By leveraging accurate parameters and mesh data, it accurately simulates turbulent flow conditions within the channel, reduces calculation errors, and provides scientifically reliable calculation results for flow field analysis of semi-welded plate exchangers, helping to optimize the device's internal flow channel design, improve fluid transmission efficiency, and enhance overall device performance.

[0057] As a possible implementation, in the above embodiment, step S4 may specifically include the following steps: S4-1. Obtain pressure drop data of the welded plate heat exchanger using the preliminary flow field calculation results; Extract the pressure values ​​at the inlet and outlet sections from the preliminary flow field calculation results. By calculating the difference between the inlet and outlet pressures, we obtain the heat exchanger's pressure drop data under different flow rate conditions. This step directly obtains the raw pressure drop data through numerical calculation, providing quantitative support for subsequent fitting processing, ensuring the accuracy and reliability of the data source, and laying the foundation for the analysis of the heat exchanger's resistance characteristics.

[0058] S4-2, performing fitting processing on the pressure drop data of the welded plate heat exchanger to obtain a fitting result of the pressure drop data; Based on multiple sets of flow rate and corresponding pressure drop data, it is assumed that the pressure drop and flow rate satisfy the quadratic function relationship, that is, Δ p =αv ²+ bv , the regression analysis method is used to solve the function coefficients and obtain a mathematical expression that can describe the relationship between pressure drop and flow rate. Among them, α = C 2 r △ n / 2, b = m △ n / α ,△ n is the thickness of the porous medium region along this direction, Δ p It is used to express the pressure drop of semi-welded plate heat exchanger, that is, the pressure difference between the inlet and outlet when the fluid passes through the heat exchanger, which is used to measure the resistance to fluid flow; v The flow rate of the fluid within the channels between the heat exchanger plates is the core variable affecting pressure drop and reflects the speed of fluid flow. This process converts discrete simulation data into continuous engineering formulas through fitting, enabling rapid prediction of pressure drop at any flow rate. This enhances the data's engineering value and provides a convenient calculation tool for heat exchanger performance evaluation.

[0059] S4-3. Verify the fitting result of the pressure drop data to obtain the fluid simulation result of the semi-welded plate-type AC; By verifying the fitting results of the pressure drop data, the accuracy of the fitting formula is ensured, so that the fluid simulation results can truly reflect the actual flow resistance characteristics of the heat exchanger, providing a reliable basis for structural optimization and energy consumption evaluation in engineering design, and enhancing the engineering practicality of the simulation method.

[0060] In summary, steps S4-1 through S4-3, starting with preliminary flow field calculation results, first extract pressure drop data for welded plate heat exchangers, a key indicator of heat exchanger performance. This pressure drop data is then fitted, using mathematical methods to identify patterns in the data and obtain more representative pressure drop data fitting results. Finally, the fitting results are verified to obtain fluid simulation results for semi-welded plate heat exchangers. This process effectively integrates preliminary calculation data and, through scientific data processing and verification, significantly improves the accuracy and reliability of pressure drop data in fluid simulation results. This provides a precise basis for evaluating the fluid transmission performance of semi-welded plate heat exchangers and optimizing equipment structural design. It helps engineers quickly identify potential equipment issues, reduces unnecessary experimental testing, accelerates product development iterations, and reduces R&D costs.

[0061] As a possible implementation, in the above embodiment, step S4-3 may specifically include the following steps: S4-3-1. Obtaining a predicted value of the fitting result based on the fitting result of the pressure drop data; S4-3-2. Compare the predicted value of the fitting result with the pressure drop data of the welded plate heat exchanger point by point to obtain a comparison error; S4-3-3. Determine whether the comparison error meets the preset comparison error value. If so, obtain the fluid simulation result of the semi-welded plate exchanger based on the fitting result of the pressure drop data. Otherwise, return to S4-2.

[0062] In summary, steps S4-3-1 to S4-3-3 calculate the predicted value based on the fitting results of the pressure drop data, compare it point by point with the pressure drop data of the semi-welded plate heat exchanger, and determine whether the comparison error meets the preset value. If it does, the fitting result is used as the fluid simulation result of the semi-welded plate heat exchanger; if it does not, the pressure drop data is refitted until a fitting result that meets the error requirements is obtained. This process ensures the accuracy and reliability of the fitting model by quantitatively comparing the fitting predicted value with the actual pressure drop data. It can effectively avoid engineering design errors caused by model deviations, provide a precise quantitative basis for heat exchanger structural optimization, pump power matching, etc., and enhance the guiding value of the simulation results for actual engineering applications. At the same time, through a closed-loop correction mechanism, the fitting model is continuously optimized, enhancing the practicality and accuracy of the entire simulation method.

[0063] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, 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 magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0064] The present invention is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. 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 one a process or multiple processes and / or boxes Figure one A device that provides the functions specified in a block or multiple blocks.

[0065] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure one a process or multiple processes and / or boxes Figure one The function specified in one or more boxes.

[0066] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure one a process or multiple processes and / or boxes Figure one A step that specifies a function in one or more boxes.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A method for simulating fluid flow in a semi-welded plate heat exchanger, characterized in that: include: S1. Using a single-side medium three-dimensional model, obtain porous medium parameters of a porous medium model; S2. Meshing the single-sided medium three-dimensional model to obtain a meshing result of the single-sided medium three-dimensional model; S3, based on the porous medium parameters of the porous medium model and the grid division results of the single-side medium three-dimensional model k - ω The SST turbulence model performs preliminary flow field calculations and obtains preliminary flow field calculation results, including: Set the single-side inlet boundary condition; Obtaining a Reynolds number based on the single-sided inlet boundary condition; Based on the Reynolds number, obtaining the turbulence intensity in the channel; The turbulence intensity in the channel is used to k - ω Initialize the SST turbulence model and obtain the initialization k - ω SST turbulence model; The porous medium parameters of the porous medium model and the grid division results of the single-side medium three-dimensional model are input into the initialization k - ω SST turbulence model, based on the single-side inlet boundary condition, performs preliminary flow field trial calculation to obtain preliminary flow field trial calculation results; S4. Perform fitting processing based on the preliminary flow field trial calculation results to obtain fluid simulation results of the semi-welded plate exchanger.

2. A semi-welded plate heat exchanger fluid simulation method according to claim 1, characterized in that: S1. Using the single-side medium three-dimensional model, obtain the porous medium parameters of the porous medium model, including: Obtain the key structural parameters of the corrugated plates through a semi-welded plate heat exchanger; Establishing a parametric three-dimensional model of the corrugated plate based on key structural parameters of the corrugated plate; A single-side medium three-dimensional model is established using the parameterized three-dimensional model of the corrugated plate to obtain porous medium parameters of the porous medium model.

3. A semi-welded plate heat exchanger fluid simulation method according to claim 2, characterized in that: The parameterized three-dimensional model of the corrugated plate is used to establish a single-side medium three-dimensional model to obtain porous medium parameters of the porous medium model, including: Assembling the parameterized three-dimensional model of the corrugated plate to obtain an assembly of the corrugated plate; Obtaining a fluid physics calculation domain based on the assembly of the corrugated sheet and Boolean operations; Performing geometric repair based on the fluid physics calculation domain to construct a single-sided medium three-dimensional model; Performing geometric feature parameter mapping on the single-sided medium three-dimensional model to obtain geometric feature parameters of the single-sided medium three-dimensional model, wherein the geometric feature parameters include corner hole shrinkage ratio, corrugation disturbance angle, equivalent hydraulic diameter and porosity; Obtaining a resistance coefficient of the porous medium model using a preset fitting coefficient according to the geometric characteristic parameters of the single-sided medium three-dimensional model, wherein the resistance coefficient of the porous medium model includes an inertial resistance coefficient and a viscous resistance coefficient of the porous medium model; Establishing a porous medium model using the resistance coefficient of the porous medium model and the porosity; Using the porous medium model and a solid model corresponding to the porous medium model, obtaining a single-side pressure drop error between the porous medium model and the solid model; determining whether a unilateral pressure drop error between the porous medium model and the solid model meets a unilateral pressure drop error threshold; if so, obtaining the porosity, the inertial resistance coefficient, the viscous resistance coefficient, and the equivalent hydraulic diameter as porous medium parameters of the porous medium model; otherwise, adjusting the preset fitting coefficient and returning to executing the first operation; The first operation is to obtain the resistance coefficient of the porous medium model using a preset fitting coefficient according to the geometric characteristic parameters of the single-sided medium three-dimensional model.

4. The method for simulating fluid flow in a semi-welded plate heat exchanger according to claim 1, wherein: S2. Meshing the single-sided medium three-dimensional model to obtain a meshing result of the single-sided medium three-dimensional model, including: Performing geometric preprocessing on the single-sided medium three-dimensional model to obtain a preprocessed single-sided medium three-dimensional model and periodic boundary conditions; Performing polyhedral mesh division on the pre-processed single-sided medium three-dimensional model based on the periodic boundary condition to obtain a mesh division result of the pre-processed single-sided medium three-dimensional model; Quality control is performed based on the preprocessed mesh division result of the single-sided medium three-dimensional model to obtain the mesh division result of the single-sided medium three-dimensional model.

5. A semi-welded plate heat exchanger fluid simulation method according to claim 4, characterized in that: Performing quality control based on the preprocessed mesh division result of the single-sided medium three-dimensional model to obtain the mesh division result of the single-sided medium three-dimensional model includes: Obtaining the distortion rate and aspect ratio of the mesh division result by preprocessing the mesh division result of the single-sided medium three-dimensional model; Determining whether the distortion rate of the meshing result meets a preset distortion rate threshold; if so, performing a second operation; otherwise, deleting the meshing result that does not meet the preset distortion rate threshold based on the meshing result of the preprocessed single-sided medium three-dimensional model, and performing the second operation; Among them, the second operation is: determine whether the aspect ratio of the grid division result meets the preset aspect ratio threshold; if so, obtain the grid division result of the pre-processed single-sided medium three-dimensional model as the grid division result of the single-sided medium three-dimensional model; otherwise, delete the grid division result that does not meet the preset aspect ratio threshold according to the grid division result of the pre-processed single-sided medium three-dimensional model, and obtain the grid division result of the single-sided medium three-dimensional model.

6. The method for fluid simulation of a semi-welded plate heat exchanger according to claim 1, characterized in that: S4. Perform fitting processing based on the preliminary flow field trial calculation results to obtain fluid simulation results of the semi-welded plate exchanger, including: Using the preliminary flow field calculation results, obtain pressure drop data of the welded plate heat exchanger; Performing fitting processing on the pressure drop data of the welded plate heat exchanger to obtain a fitting result of the pressure drop data; The fitting results of the pressure drop data are verified to obtain the fluid simulation results of the semi-welded plate exchanger.

7. A method for simulating fluid flow in a semi-welded plate heat exchanger according to claim 6, characterized in that: Verify the fitting results of the pressure drop data to obtain the fluid simulation results of the semi-welded plate exchanger, including: Obtaining a predicted value of the fitting result through the fitting result of the pressure drop data; performing point-by-point comparison based on the predicted value of the fitting result and the pressure drop data of the welded plate heat exchanger to obtain a comparison error; Determine whether the comparison error meets a preset comparison error value; if so, obtain a fluid simulation result of the semi-welded plate alternator according to the fitting result of the pressure drop data; otherwise, return to perform the third operation; The third operation is to perform fitting processing on the pressure drop data of the welded plate heat exchanger to obtain a fitting result of the pressure drop data.

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