Micro-channel heat exchanger with shark-skin structure and manufacturing method thereof

Abstract

This invention relates to the field of microchannel heat dissipation technology, and discloses a microchannel heat exchanger with a shark-scale-like structure and its manufacturing method. The heat exchanger includes a microchannel substrate with multiple parallel V-shaped grooves on its surface. The length direction of the V-shaped grooves is parallel to the flow direction of the working fluid, and fan-shaped scale structures are arrayed on the inclined surface of the V-shaped grooves. The tips of the scale structures face away from the flow direction of the working fluid, and several grooves are provided on the upper surface of the scale structures. The cross-sectional area of ​​the grooves and the ridges between the grooves gradually increases along the flow direction of the working fluid. This microchannel substrate, through its shark-scale-like structure, enhances the heat exchange effect while reducing or not significantly increasing the flow resistance of the cooling working fluid, thus reducing the energy consumption required to drive the flow of the working fluid while ensuring heat exchange efficiency. The microchannel substrate in this microchannel heat exchanger is manufactured using laser selective melting 3D printing technology, which can efficiently achieve the integrated molding of the microchannel substrate.

Description

Technical Field

[0001] This invention relates to the field of microchannel heat dissipation technology, specifically to a microchannel heat exchanger with a shark-scale-like structure and its manufacturing method. Background Technology

[0002] Currently, electronic components are developing towards integration, high frequency, and functional complexity. As their feature size decreases, their heat flux density increases dramatically. Exploring more efficient heat dissipation methods is one of the main technical challenges in further improving the performance of integrated electronic components. Microchannel heat exchangers, due to their light weight, small size, and good heat dissipation performance, are considered an ideal solution to the high heat flux density of micro-components. Traditional microchannel heat exchangers are fabricated on metal or silicon substrates using rectangular, triangular, or trapezoidal microchannel array structures with smooth walls. However, these methods suffer from problems such as small heat transfer area, limited heat transfer performance, and low critical heat flux density. To address this, researchers have proposed incorporating microstructures such as turbulent micropillars, porous coatings, and recessed structures on the microchannel walls. These can significantly increase the heat transfer area, disrupt the normal development of the boundary layer, and increase boiling phase change nuclei, thereby enhancing heat transfer. However, these enhanced structures significantly increase flow pressure drop and resistance, thus increasing pump work, causing energy waste, and bringing adverse effects. Therefore, it is urgent to design novel microchannel structures that can enhance heat transfer while reducing flow resistance. Summary of the Invention

[0003] In order to overcome the shortcomings of the prior art, the present invention aims to provide a microchannel heat exchanger with a shark scale-like structure, which can increase the heat exchange area and disrupt the continuous development of the boundary layer while avoiding a significant increase in the flow resistance of the working fluid and reducing the energy consumption required to drive the fluid.

[0004] To solve the above problems, the technical solution adopted by the present invention is as follows: A microchannel heat exchanger with a shark-scale-like structure includes a microchannel substrate. The surface of the microchannel substrate is provided with multiple parallel V-shaped grooves. The length direction of the V-shaped grooves is parallel to the flow direction of the working fluid. Fan-shaped scale structures are arrayed on the inclined surface of the V-shaped grooves. The tips of the scale structures face away from the flow direction of the working fluid. The upper surface of the scale structures forms a certain angle with the inclined surface of the V-shaped grooves along the flow direction of the working fluid. Several grooves are provided on the upper surface of the scale structures. The cross-section of the grooves is fan-shaped. The cross-sectional area of ​​the grooves and the ridges between the grooves gradually increases along the flow direction of the working fluid. The width and depth of the grooves gradually increase along the flow direction of the working fluid. The height of the ridges gradually increases along the flow direction of the working fluid. Both the grooves and the ridges are composed of smooth curved surfaces.

[0005] In the aforementioned microchannel substrate, the cross-section of the V-shaped groove is an isosceles triangle, the depth-to-width ratio of the V-shaped groove is in the range of 1:1-2:1, and the angle of the inclined surface of the V-shaped groove is greater than or equal to 60°.

[0006] In the aforementioned microchannel substrate, the dimensionless height and dimensionless spacing of the V-shaped grooves are both less than or equal to 30.

[0007] In the aforementioned microchannel substrate, the hydraulic diameter of the V-shaped groove ranges from 0.5 to 1 mm.

[0008] In the aforementioned microchannel substrate, the angle between the upper surface of the scale structure and the inclined surface of the V-shaped groove ranges from 20° to 45°.

[0009] In the aforementioned microchannel substrate, the characteristic size of the groove ranges from 30 to 80 μm, and the characteristic size of the ridge ranges from 20 to 60 μm.

[0010] A method for manufacturing the above-mentioned microchannel substrate includes the following steps:

[0011] 1) Design a three-dimensional model of the microchannel substrate;

[0012] 2) Import the 3D model into the laser selective melting slicing software and adjust the model to the optimal printing position;

[0013] 3) Select metal powder and use a laser selective melting 3D printing equipment to print the powder layer by layer, and print a microchannel matrix with a shark scale-like structure according to the three-dimensional model;

[0014] 4) Remove the microchannel substrate and perform ultrasonic cleaning;

[0015] 5) The microchannel substrate with a shark scale-like structure is welded and encapsulated with the upper and lower cover plates, and connected to the external pipeline and pump to form a circulation loop, thus obtaining a complete microchannel heat exchanger.

[0016] In the above-mentioned method for manufacturing microchannel heat exchangers, the laser power range of the laser selective melting 3D printing equipment for printing the microchannel substrate is 100-200W.

[0017] In the above-mentioned method for manufacturing microchannel heat exchangers, the laser selective melting 3D printing equipment has a printing speed range of 50-100 mm / s for printing the microchannel substrate, a slice thickness of 20-40 μm, and a path distance range of 0.01-0.05 mm.

[0018] In the above-mentioned method for manufacturing microchannel heat exchangers, the particle size range of the metal powder is 10-30 μm.

[0019] The significant advantages of this invention compared to existing technologies are:

[0020] 1) This microchannel structure can significantly increase the heat transfer area of ​​the microchannel by arranging shark scale-like structures on the inclined surface of the V-shaped groove, thereby disrupting the normal development of the boundary layer, promoting turbulence, and thus enhancing heat transfer.

[0021] 2) The scale structure of the biomimetic shark scale microtexture is arranged on the inclined surface of the V-shaped groove. The inclined ridge and fan-shaped groove structure of the fish scale microtexture generate a low-speed secondary vortex at the rear end of the texture, which reduces the momentum exchange of the flow boundary layer and reduces the near-wall viscous resistance, thereby reducing the pump work and the energy required to drive the cooling working fluid.

[0022] 3) By utilizing selective laser melting technology, it is possible to achieve efficient integrated forming of microchannels and their shark scale-like wall structures, giving full play to the advantages of selective laser melting in rapid forming and its suitability for processing complex three-dimensional structures, while realizing the integrated forming of microchannels and millimeter-level microtextures.

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0024] Figure 1 This is a three-dimensional structural diagram of a microchannel heat exchanger according to an embodiment of the present invention;

[0025] Figure 2 This is a three-dimensional structural diagram of the microchannel substrate according to an embodiment of the present invention;

[0026] Figure 3 This is a front view of the microchannel substrate structure according to an embodiment of the present invention;

[0027] Figure 4 This is a three-dimensional structural diagram of the scale structure according to an embodiment of the present invention;

[0028] Figure 5 This is a top view of the scale structure according to an embodiment of the present invention;

[0029] Figure 6 This is a front view of the scale structure according to an embodiment of the present invention;

[0030] Figure 7 This is a side view of the scale structure according to an embodiment of the present invention;

[0031] Figure 8 This is a flowchart of a method for manufacturing a microchannel substrate according to an embodiment of the present invention.

[0032] Explanation of icon numbers:

[0033] 100 Microchannel substrate, 110 V-groove, 120 Scale structure, 121 Groove, 122 Ridge, 200 Lower cover plate, 300 Upper cover plate. Detailed Implementation

[0034] The embodiments of the present invention are described in detail below, with reference to... Figures 1 to 7 This invention provides a microchannel heat exchanger with a shark-scale-resistant structure, comprising an upper cover plate 300, a lower cover plate 200, and a cavity formed by the upper cover plate 300 and the lower cover plate 200. The cavity has an outlet and an inlet at both ends for the cooling medium to flow in and out. The surface of the microchannel substrate 100 has multiple parallel V-shaped grooves 110, the direction of which is parallel to the flow direction of the cooling medium. Fan-shaped scale structures 120 are arrayed on the inclined surface of the V-shaped grooves 110, with the tips of the scale structures 120 facing away from the flow direction of the cooling medium. (Refer to...) Figures 4 to 7 The upper surface of the scale structure 120 forms a certain angle with the inclined surface of the V-shaped groove 110 along the flow direction of the working fluid. Several fan-shaped grooves 121 are provided on the upper surface of the scale structure 120. The cross-sectional area of ​​the grooves 121 and the ridges 122 between them gradually increases along the flow direction of the working fluid. The width and depth of the grooves 121 gradually increase along the flow direction of the working fluid, and the height of the ridges 122 gradually increases along the flow direction of the working fluid. Both the grooves 121 and the ridges 122 are composed of smooth curved surfaces.

[0035] The microchannel substrate 100 of this invention mimics the microtexture of shark skin by arraying scale structures 120 on the inclined surface of V-shaped grooves 110 and setting grooves 121 on the scale structures 120. This simplifies the overlapping scales mimicking the "cortical scale protrusions" of shark skin, improving drag reduction and lowering the resistance of the cooling working fluid flowing through the microchannel substrate 100. The cross-sectional area of ​​the ridges 122 and grooves 121 on the scale structures 120 gradually increases along the flow direction of the working fluid, making the height and width of the grooves 121 and ridges gradually increase along the flow direction, which is beneficial for the smooth flow of the working fluid. The V-shaped grooves 110 and scale structures 120 have a height difference, which causes the working fluid to preferentially converge at the troughs of the grooves 121 in the V-shaped grooves 110 and scale structures 120, thereby effectively limiting the lateral flow of the working fluid and reducing the intensity of turbulence. The working fluid flows into the microchannel and is divided into multiple flow paths by the arrayed fin structure 120, effectively breaking the thermal boundary layer and improving heat transfer efficiency. Simultaneously, due to the height difference between the longitudinal and lateral protrusions, the working fluid moves along the ridge 122, with minimal lateral movement. This causes the fluid within the groove 121 of the fin structure 120 to be dominated by viscous forces, hindering fluid flow in this area and increasing the thickness of the viscous sublayer, effectively reducing the average velocity gradient on the wall surface. The ridge 122 and groove 121 structure effectively confine the water flow within the groove 121, thereby significantly reducing fluid resistance. This microchannel substrate 100 can improve heat transfer efficiency while reducing the flow resistance of the cooling working fluid, thus reducing the energy required to pump the working fluid and lowering the energy consumption of the heat exchanger.

[0036] Furthermore, the surfaces of the grooves 121 and ridges 122 of the microchannel substrate 100 are both composed of smooth curved surfaces, making the cross-sections of the grooves 121 and ridges 122 fan-shaped. According to the second eddy theory, the inclined ridges 122 and the eddy currents interact within the fan-shaped grooves 121 to generate secondary eddies. These secondary eddies retain low-speed fluid within the grooves 121, limiting the concentration of low-momentum fluid. In addition, these secondary eddies can act as "rolling bearings," changing the friction between the fluid and the wall from sliding friction to rolling friction, further reducing flow resistance.

[0037] It is understood that the V-shaped groove 110 should preferably adopt a symmetrical structure. In this embodiment, the cross-section of the V-shaped groove 110 is an isosceles triangle. The scale structure 120 is symmetrically arranged on the inclined surfaces on both sides of the V-shaped groove 110, with three rows of scale structures 120 arranged in an array on each inclined surface. The depth-to-width ratio of the V-shaped groove 110 should preferably be between 1:1 and 2:1, the angle of the inclined surface should be greater than or equal to 60°, and the dimensionless height and dimensionless spacing of the V-shaped groove 110 should both be less than or equal to 30. Exceeding this range will result in increased drag. The hydraulic diameter of the V-shaped groove 110 should be between 0.5 and 1 mm.

[0038] Reference Figures 3 to 6 In this embodiment, each scale structure 120 has two grooves 121 and three ridges 122 on its upper surface. The three ridges 122 and two grooves 121 are radially arranged on the upper surface of the scale structure 120 with the center of the scale structure 120 as the radial center. The angles of the three ridges 122 are equally spaced. The inclination angle between the upper surface of the scale structure 120 and the inclined surface of the V-shaped groove 110 is preferably in the range of 20°-45°. The characteristic size of the groove 121 is preferably in the range of 30-80 μm, and the characteristic size of the ridge 122 is preferably in the range of 20-60 μm.

[0039] To reduce the manufacturing cost of the microchannel substrate 100, refer to Figure 7 The microchannel substrate 100 of this invention is manufactured using a selective laser melting (SLM) 3D printing process, which is a major technical approach in additive manufacturing of metal materials. It is suitable for forming complex-shaped metal micro-weaves and can integrally shape the microchannel substrate 100 of this invention. The post-processing only requires one wire cutting and cleaning / drying step, resulting in a simple manufacturing process and low processing cost. Specific steps include:

[0040] 1) Design a three-dimensional model of the microchannel substrate 100. In this embodiment, Solidworks software is used to build a three-dimensional model of the microchannel substrate 100, and the model is saved as an STL format after the model is built.

[0041] 2) Import the 3D model in STL format into the laser melting and slicing software Magics, and use the software commands to adjust the model to the optimal printing position so that the substrate and the forming substrate can make good contact.

[0042] 3) Select metal powder, set the printing parameters of the laser selective melting 3D printing equipment, and use the laser selective melting 3D printing equipment to print powder layer by layer, printing a microchannel substrate 100 with a shark scale-like structure according to the three-dimensional model. In this embodiment, the particle size range of the metal powder is preferably 10-30um, the laser power range is preferably 100-200W, the printing speed range is preferably 50-100mm / s, the slice thickness is preferably 20um, the filling pattern type is preferably set to no pattern, and the path distance range is preferably 0.01-0.05mm. Before starting printing, clean the forming chamber and wipe the laser lens with alcohol, align the blade and properly place the printing substrate, add metal powder to the equipment, open the nitrogen cylinder to inject safety gas into the equipment, and start printing when the safety gas content reaches the target value. The equipment will automatically print powder layer by layer.

[0043] 4) Remove the microchannel substrate 100 and perform ultrasonic cleaning; after printing, cut the printed microchannel substrate 100 from the molding substrate by wire cutting, then put the microchannel substrate 100 into a sealed bag filled with alcohol, and put the sealed bag into an ultrasonic cleaner for 5 minutes. After cleaning, take out the sample of microchannel substrate 100 with tweezers and dry the sample with a hair dryer.

[0044] 5) The microchannel substrate 100 with the shark-proof structure is welded and encapsulated with the upper cover plate 300 and the lower cover plate 200, and connected to the external pipeline and pump to form a circulation loop, thus obtaining a complete microchannel heat exchanger.

[0045] It should be noted that in the description of this invention, any descriptions of orientation, such as up, down, front, back, left, right, etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings. They are only for the purpose of facilitating the description of this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed or operated in a specific orientation, and should not be construed as a limitation of this invention.

[0046] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," "exceeding," etc. are understood to exclude the stated number, while "above," "below," "within," etc. are understood to include the stated number. If "first" or "second" is mentioned, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0047] In the description of this invention, unless otherwise explicitly defined, terms such as "setting," "installing," and "connecting" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0048] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A microchannel heat exchanger with a shark-scale-like structure, characterized in that, The system includes a microchannel substrate (100) with multiple parallel V-shaped grooves (110) on its surface. The length direction of the V-shaped grooves (110) is parallel to the flow direction of the working fluid. Fan-shaped scale structures (120) are arrayed on the inclined surface of the V-shaped grooves (110), with the tips of the scale structures (120) facing away from the flow direction of the working fluid. The upper surface of the scale structures (120) is inclined at an angle to the inclined surface of the V-shaped grooves (110) along the flow direction of the working fluid. The upper surface of the scale structure (120) is provided with a plurality of grooves (121). The cross-section of the grooves (121) is fan-shaped. The cross-sectional area of ​​the grooves (121) and the ridges (122) between the grooves (121) gradually increases along the flow direction of the working fluid. The width and depth of the grooves (121) gradually increase along the flow direction of the working fluid. The height of the ridges (122) gradually increases along the flow direction of the working fluid. Both the grooves (121) and the ridges (122) are composed of smooth curved surfaces.

2. The microchannel heat exchanger with a shark-scale-like structure according to claim 1, characterized in that, The cross-section of the V-shaped groove (110) is an isosceles triangle, the depth-to-width ratio of the V-shaped groove (110) is in the range of 1:1-2:1, and the angle of the inclined surface of the V-shaped groove (110) is greater than or equal to 60°.

3. The microchannel heat exchanger with a shark-scale-like structure according to claim 1, characterized in that, The hydraulic diameter of the V-groove (110) ranges from 0.5 to 1 mm.

4. The microchannel heat exchanger with a shark-scale-like structure according to claim 1, characterized in that, The angle between the upper surface of the scale structure (120) and the inclined surface of the V-groove (110) ranges from 20° to 45°.

5. The microchannel heat exchanger with a shark-scale-like structure according to claim 1, characterized in that, The characteristic dimensions of the groove (121) range from 30 to 80 μm, and the characteristic dimensions of the ridge (122) range from 20 to 60 μm.

6. A method for manufacturing a microchannel heat exchanger with a shark-scale-like structure according to any one of claims 1 to 5, comprising the following steps: 1) Design a three-dimensional model of the microchannel substrate (100); 2) Import the 3D model into the laser selective melting slicing software and adjust the model to the optimal printing position; 3) Select metal powder and use a laser selective melting 3D printing equipment to print the powder layer by layer, and print a microchannel matrix (100) with a shark scale structure according to the three-dimensional model. 4) Remove the microchannel substrate and perform ultrasonic cleaning; 5) The microchannel substrate (100) with shark scale-like structure is welded and encapsulated with the upper cover plate (300) and the lower cover plate (200), and connected to the external pipeline and pump to form a circulation loop to obtain a complete microchannel heat exchanger.

7. The method for manufacturing a microchannel heat exchanger according to claim 6, characterized in that, The laser power range for printing the microchannel substrate (100) using the laser selective melting 3D printing equipment is 100-200W.

8. The method for manufacturing a microchannel heat exchanger according to claim 6, characterized in that, The laser selective melting 3D printing equipment prints microchannel substrates (100) at a speed ranging from 50 to 100 mm / s, with a slice thickness of 20 to 40 μm and a path distance ranging from 0.01 to 0.05 mm.

9. The method for manufacturing a microchannel heat exchanger according to claim 6, characterized in that, The particle size range of the metal powder is 10-30 μm.

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