Design method for double-channel heat exchanger structure based on bionic gradient TPMS (Tire Pressure Monitor System)

Abstract

The invention provides a bionic gradient-based TPMS double-channel heat exchanger structure design method, which relates to the technical field of heat exchanger design, and comprises the following steps: S1, creating a cube reference model, determining the position of each node in the reference model according to the spatial topological relation of a diamond crystal structure, and carrying out three-dimensional space connection to form a diamond unit cell support structure; s2, parametric modeling of the multiple tubular objects is conducted through a curved surface tool according to the diamond unit cell support structure, and a tubular curved surface network is generated; s3, performing equidistant offset operation on the tubular curved surface network to obtain a TPMS unit cell structure; s4, performing three-dimensional array on the TPMS unit cell structure to obtain an HRD lattice structure model; and S5, carrying out gradient parameterization regulation and control on the diameter of the fluid channel of the HRD lattice structure model. The heat exchanger has the beneficial effects that unification of light weight and high rigidity is achieved, and the heat exchange efficiency can be remarkably improved while high rigidity and light weight are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat exchanger design, and particularly relates to a structure design method of a bionic gradient TPMS double-flow heat exchanger. BACKGROUND

[0002] In the field of high-efficiency heat exchanger design, the triple periodic minimal surface (TPMS) structure has become an important solution to realize lightweight and high-efficiency heat exchange due to its continuous smooth surface, high specific surface area and through porosity. However, the existing TPMS heat exchanger design has significant limitations: on the one hand, the research on mechanical properties and thermal properties is often relatively independent, and there is a lack of multi-physical field comprehensive optimization method of force-heat-flow; on the other hand, the traditional structure parameter control means is single, and it is difficult to meet the high standard requirements of comprehensive performance under complex working conditions in the fields of aviation, aerospace, energy and power. Especially with the development of double-flow integrated technology, the force-heat coupling effect inside the structure is increasingly complex, which further highlights the deficiency of multi-objective optimization capability. SUMMARY

[0003] Therefore, in order to solve the problem that the heat transfer performance and mechanical performance of the TPMS structure heat exchanger cannot be balanced, the embodiments of the present application provide a structure design method of a bionic gradient TPMS double-flow heat exchanger.

[0004] The embodiments of the present application provide a structure design method of a bionic gradient TPMS double-flow heat exchanger, which comprises the following steps: S1, a cubic reference model is created, and the position of each node is determined according to the spatial topological relationship of the diamond crystal structure and is connected in three-dimensional space to form a diamond single cell support structure; S2, a parametric modeling of multi-tubular objects is performed according to the diamond single cell support structure by using a curved surface tool to generate a tubular curved surface network; S3, an offset operation is performed on the tubular curved surface network to obtain a TPMS single cell structure; S4, a three-dimensional array is performed on the TPMS single cell structure to obtain an HRD point array structure model; S5, a gradient parameterization control is performed on the fluid channel diameter of the HRD point array structure model.

[0005] Further, in the step S5, the gradient parameterization control is performed on the fluid channel diameter of the HRD point array structure model by using a Sub-D technology.

[0006] Further, based on a trilinear interpolation or a neighborhood mean iterative optimization algorithm, the pipe diameter is adjusted along the Y axis in the XOZ central plane of the HRD point array structure model.

[0007] Further, the fluid channel diameter of the HRD lattice structure model is increased by gradient from the XOZ center to both ends of the Y axis.

[0008] Further, the fluid channel diameter of the HRD lattice structure model is decreased by gradient from the XOZ center to both ends of the Y axis.

[0009] Further, the tubular curved surface network is generated by using a subdivision surface tool in the step S2.

[0010] Further, the 3D modeling software is used.

[0011] Further, the additive manufacturing file is generated according to the HRD lattice structure model after gradient parameterization regulation.

[0012] Further, the length, width and height of the TPMS unit cell structure range from 4 to 15 mm, and the wall thickness is 0.25 to 3 mm.

[0013] Further, the shape of the HRD lattice structure model is a cube.

[0014] The technical scheme provided by the embodiment of the application has the following beneficial effects: The application provides a structure design method of a bionic gradient TPMS double-flow heat exchanger, which comprises the following steps: generating a tubular curved surface network by parameterized modeling of a plurality of tubular objects according to a diamond cell support structure; and obtaining a TPMS unit cell structure similar to a multi-segmented starfish skeleton by offsetting and adding wall thickness, wherein the TPMS unit cell structure is completely extended by millimeter-sized otic capsules and exhibits a periodic porous microcrystalline lattice structure. By referring to the progressive collapse mechanism of the starfish skeleton, a rod-shaped support network is designed, so that the high-porosity central area of the structure is preferentially deformed to absorb energy when the structure is under pressure, and the low-porosity edge area is delayed to support and maintain stability, thereby forming a time-space gradient deformation mode. The progressive collapse of the structure is generated when the structure is under pressure due to the progressive change in the thickness of the support rods from the inside to the outside, and the special lattice defect distribution in the interior can effectively inhibit crack propagation. The three-dimensional through diamond lattice realizes the unification of lightweight and high stiffness. Meanwhile, based on the vortex field strengthening principle of the deep-sea glass sponge, the reverse flow shear effect is generated by regulating the internal flow channel curvature, the turbulent mixing is enhanced, the fluid exchange is strengthened by the vortex field, the heat exchange efficiency is improved under low flow rate conditions, the high stiffness and light weight are realized, and the heat exchange efficiency is significantly improved, thereby meeting the harsh working condition requirements of light weight and high efficiency heat exchanger in the fields of aviation, aerospace, energy and power. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a modeling process schematic diagram of the HRD lattice structure model; Figure 2 is a schematic diagram of different cross-sectional porosities of two types of gradient variants; Figure 3This is a schematic diagram of a biomimetic gradient TPMS dual-channel heat exchanger structure. Figure 4 This is a comparison of stress-strain curves based on a biomimetic gradient TPMS dual-channel heat exchanger structure. Figure 5 These are structural diagrams of the GHRD1 heat exchanger and performance test diagrams of the GHRD2 heat exchanger. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described below with reference to the accompanying drawings. The following description presents a preferred embodiment of the various possible embodiments of the present invention, intended to provide a basic understanding of the invention, but not intended to identify key or decisive elements of the invention or to limit the scope of protection sought.

[0017] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0018] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0019] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures. Also, it should be understood that, for ease of description, the dimensions of the various parts shown in the figures are not drawn to actual scale.

[0020] Please refer to Figure 1 The embodiments of the present invention provide a structural design method for a biomimetic gradient TPMS dual-channel heat exchanger, which mainly includes the following steps S1-S5.

[0021] S1. Create a cubic reference model. Within the reference model, determine the position of each node according to the spatial topological relationship of the diamond crystal structure and connect them in three-dimensional space to form a diamond unit cell scaffold structure.

[0022] Specifically, such as Figure 1 As shown in Figure a, the basic geometric units are constructed using the modeling function of 3D modeling software, creating a cube as a reference model. Then, based on the spatial topological relationship of the diamond crystal structure, the positions of each node within the reference model are determined, and the nodes are connected to form a diamond unit cell scaffold structure within the reference model. The 3D modeling software used can be Rhino, such as Rhino 8.0 used in this embodiment.

[0023] S2, parametric modeling of multi-tubular objects according to the diamond cell scaffold structure is performed using a curved surface tool to generate a tubular curved surface network. Specifically, as shown in b, the tubular curved surface network is generated by controlling the pipe diameter variation parameter using the subdivision surface tool in the software Rhino 8.0. Figure 1

[0024] S3, offset operation is performed on the tubular curved surface network to obtain a TPMS cell structure. Specifically, as shown in c, the offset operation is performed on the tubular curved surface network in the software Rhino 8.0 using the intelligent offset command to obtain a TPMS cell structure with wall thickness control. The offset distance is the wall thickness of the TPMS cell structure, which can be flexibly set according to the actual application scenario. Generally, the wall thickness is set to 0.25-3mm. In this embodiment, the offset distance is 0.5mm, i.e. a wall thickness of 0.5mm is formed. Figure 1

[0025] The structure of the TPMS cell structure is similar to the skeleton structure of the multi-segment starfish. The design of the gradually changing strut thickness from inside to outside makes the structure produce progressive collapse rather than sudden fracture under pressure, and the special lattice defect distribution in the interior can effectively inhibit crack propagation. This three-dimensional through diamond lattice realizes the unification of lightweight and high stiffness. The TPMS cell structure learns from the progressive collapse mechanism of the starfish skeleton and adopts a rod-shaped support network design, so that the high-porosity central region of the structure deforms and absorbs energy first under pressure, and the low-porosity edge region delays support to maintain stability, forming a spatiotemporal gradient deformation pattern.

[0026] S4, three-dimensional array is performed on the TPMS cell structure to obtain a hollow tubular diamond structure model, i.e. a HRD lattice structure model. In this embodiment, the TPMS cell structure is periodically expanded by 3x3x3 through three-dimensional array, and finally a complete HRD lattice structure model is formed as shown in d. Figure 1

[0027] The final shape and specifications of the HRD lattice structure model can be flexibly selected according to the actual heat exchanger application scenario. In this embodiment, according to the design of the heat exchanger size, the shape of the HRD lattice structure model is determined to be a cube. The length, width and height of the TPMS cell structure can be set to 4-15mm. In this embodiment, the length, width and height of the TPMS cell structure are all 10mm, and a 3x3x3 array is formed in a 30mmx30mmx30mm space to form the HRD lattice structure model.

[0028] S5, gradient parametric control is performed on the fluid channel diameter of the HRD lattice structure model.

[0029] ​​​Specifically, by using a curved surface modeling technology, such as a Sub-D (Subdivision Surface) technology and a Nurbs technology, the fluid channel diameter of the HRD lattice structure model is gradient parameterized regulated and controlled by using the Sub-D technology. Based on a three-linear interpolation or a neighborhood mean iterative optimization algorithm, the pipe diameter is adjusted along the Y axis in both directions on the XOZ central plane of the HRD lattice structure model. By using the gradient parameter correlation between the mechanical energy absorption (high porosity area) and the fluid performance (inlet and outlet expansion), the force-heat-flow coupling optimization is realized.

[0030] Therefore, the gradient parameterized regulation and control of the present application can generate two types of gradient variants as shown in the following table: Figure 2 GHRD1 type: the fluid channel diameter of the HRD lattice structure model is gradient reduced from the XOZ central plane to both ends of the Y axis.

[0031] GHRD2 type: the fluid channel diameter of the HRD lattice structure model is gradient increased from the XOZ central plane to both ends of the Y axis.

[0032] As shown in the following table, the HRD lattice structure model after the gradient parameterized regulation and control is sealed, and the double-channel integrated structure with physical isolation of cold and hot channels can be obtained. Figure 3

[0033] In addition, considering the manufacturing problem of the heat exchanger, the structure design method of the bionic gradient TPMS double-channel heat exchanger of the present application further comprises generating an additive manufacturing file according to the HRD lattice structure model after the gradient parameterized regulation and control. Specifically, the HRD lattice structure model after the gradient parameterized regulation and control is input into the software Materialise Magics 24.0 for geometry repair, and then imported into the FastLayer additive manufacturing pre-processing software to generate support, and then exported as an additive manufacturing file in the SCAN format. Subsequently, the additive manufacturing file in the SCAN format is input into a selective laser melting (SLM) device for preparation, and the additive manufacturing of the heat exchanger can be completed. The process parameters of the additive manufacturing can be selected as follows: laser power 125 W, scanning speed 900 mm / s, layer thickness 0.025 mm, and scanning spacing 0.07 mm.

[0034] The present embodiment also respectively tests the performance of the GHRD1 type heat exchanger structure and the GHRD2 type heat exchanger structure corresponding to the HRD lattice structure model of the GHRD1 type and the GHRD2 type, and finds that the mechanical and thermodynamic performance of the GHRD2 type heat exchanger structure is more excellent.

[0035] The mechanical performance verification is performed by using a universal testing machine for Z-axis uniaxial compression test (speed 1 mm / min). As shown in the following table, the GHRD2 type heat exchanger structure has better mechanical performance than the GHRD1 type heat exchanger structure. Figure 4 ​​As shown in the results, the GHRD2 heat exchanger structure has a specific energy absorption of 22.86 J / g, which is 3.6% higher than that of the homogeneous HRD. The deformation presents a spatiotemporal gradient characteristic: the high-porosity central region preferentially collapses to absorb energy, and the low-porosity edge region delays deformation to provide support, achieving a balance between energy absorption and stability. Finite element simulation (Abaqus software) is highly consistent with the experiment, confirming that the GHRD2 heat exchanger structure has a uniform compression stress distribution, avoiding the local buckling of the Primitive structure and the shear instability of the Diamond structure.

[0036] The thermal performance was simulated by software ANSYS Fluent 2022 R1 through flow-thermal coupling, as shown in Figure 3 The cold / hot fluid (water) inlet temperature was set to 293.15 K / 343.15 K, the volume flow rate was 180-2000 ml / min, and the k-ω SST turbulence model was adopted. As shown in Figure 5 The results show that the heat transfer efficiency E of the GHRD2 heat exchanger structure is 39.45%, which is 50.47% higher than that of the Primitive structure. The Nusselt number Nu is better than that of the homogeneous HRD heat exchanger when Re>700, the counterflow shear effect enhances fluid mixing, and the Reynolds number Re describes the properties of fluid flow under different conditions by measuring the ratio of fluid inertia to viscous force. When the Reynolds number is small, the flow is usually dominated by laminar flow; when the Reynolds number is large, the flow tends to be turbulent; the GHRD2 heat exchanger structure has the largest Fanning friction coefficient f, and the gradient expansion design of the inlet and outlet pipe diameters reduces the pressure drop to 133 Pa under the 1800 ml / min working condition, which is 74.7% lower than that of the homogeneous HRD heat exchanger. Comprehensive performance evaluation shows that the GHRD2 heat exchanger structure has the optimal unit volume heat transfer (Qv) and unit mass heat transfer (Qm).

[0037] Finally, through force-thermal coupling optimization, the GHRD2 heat exchanger structure simultaneously realizes high specific energy absorption (22.86 J / g), low flow resistance (pressure drop of 133 Pa), and high heat transfer efficiency (39.45%), meeting the harsh working condition requirements of lightweight and efficient heat exchangers in the fields of aerospace, energy power, etc.

[0038] In this article, the front, back, up, down, and other orientation words are defined based on the positions of the components in the drawings and the positions of the components relative to each other, only to express the clarity and convenience of the technical scheme. It should be understood that they are relative concepts and can be changed accordingly according to different ways of use and placement. The use of the orientation words should not limit the scope of the application claimed.

[0039] In the case of no conflict, the above-mentioned embodiments and features in the embodiments can be combined with each other. The above-mentioned only is the preferred embodiment of the present application, and does not limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A structural design method for a biomimetic gradient TPMS dual-channel heat exchanger, characterized in that: Includes the following steps: S1. Create a cubic reference model. Within the reference model, determine the position of each node according to the spatial topological relationship of the diamond crystal structure and connect them in three-dimensional space to form a diamond unit cell scaffold structure. S2. Using surface tools, parametric modeling of multi-tubular objects is performed based on the diamond unit cell scaffold structure to generate a tubular surface network. S3. Perform an equidistant offset operation on the tubular curved surface network to obtain the TPMS unit cell structure; S4. Perform a three-dimensional array on the TPMS unit cell structure to obtain the HRD lattice structure model. S5. Gradient parameterization is applied to control the diameter of the fluid channels in the HRD lattice structure model.

2. The structural design method for a biomimetic gradient TPMS dual-channel heat exchanger as described in claim 1, characterized in that: In step S5, the diameter of the fluid channel in the HRD lattice structure model is controlled by gradient parameterization using Sub-D technology.

3. The structural design method for a biomimetic gradient TPMS dual-channel heat exchanger as described in claim 2, characterized in that: Based on trilinear interpolation or neighborhood mean iterative optimization algorithms, the pipe diameter is adjusted bidirectionally along the Y-axis on the XOZ center plane of the HRD lattice structure model.

4. The structural design method for a biomimetic gradient TPMS dual-channel heat exchanger as described in claim 3, characterized in that: The diameter of the fluid channel in the HRD lattice structure model increases gradually from the center of the XOZ towards both ends of the Y-axis.

5. The structural design method for a biomimetic gradient TPMS dual-channel heat exchanger as described in claim 3, characterized in that: The diameter of the fluid channel in the HRD lattice structure model decreases gradually from the center of the XOZ towards both ends of the Y-axis.

6. The structural design method for a biomimetic gradient TPMS dual-channel heat exchanger as described in claim 1, characterized in that: In step S2, a tubular surface network is generated using the subdivision surface tool.

7. The structural design method for a biomimetic gradient TPMS dual-channel heat exchanger as described in claim 1, characterized in that: This is achieved using 3D modeling software.

8. The structural design method for a biomimetic gradient TPMS dual-channel heat exchanger as described in claim 1, characterized in that: It also includes generating additive manufacturing files based on the HRD lattice structure model after gradient parameterization.

9. The structural design method for a biomimetic gradient TPMS dual-channel heat exchanger as described in claim 1, characterized in that: The length, width, and height of the TPMS unit cell structure range from 4 to 15 mm, and the wall thickness is 0.25 to 3 mm.

10. The structural design method for a biomimetic gradient TPMS dual-channel heat exchanger as described in claim 1, characterized in that: The HRD lattice structure model is cube-shaped.

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