Bionic micro-channel liquid cooling heat dissipation structure and preparation method thereof

Abstract

The application relates to the technical field of liquid cooling heat dissipation, in particular to a liquid cooling heat dissipation structure based on bionic microchannels and a preparation method, which comprises a liquid cooling plate main body, a turbulent flow generating assembly and a gradient heat sink composite layer, the liquid cooling plate main body is internally provided with a fractal bionic microchannel, the fractal bionic microchannel comprises a main channel and at least four levels of branch channels, wherein the last level of branch channels is distributed in the form of logarithmic spiral lines; the turbulent flow generating assembly is composed of staggered triangular prisms and hemispherical pit arrays; and the gradient heat sink composite layer comprises a copper composite substrate containing diamonds and a surface micro-nano structure. The bionic microchannel structure is combined with the microchannel with specific parameters, the efficient material transmission system in a biological body is simulated, the flow uniformity of the cooling liquid is optimized, the generation of local hot spots is reduced, and the overall heat dissipation performance is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of liquid cooling heat dissipation, in particular to a bionic micro-channel liquid cooling heat dissipation structure and a preparation method thereof. BACKGROUND

[0002] In the prior art, a micro-channel heat dissipation structure with a bionic structure and a heat dissipation device are disclosed in Chinese Patent Application No. CN202310217469.X, which relates to the technical field of electronic component heat dissipation. The micro-channel heat dissipation structure comprises a primary heat dissipation flow channel, a plurality of secondary heat dissipation flow channels connected to the primary heat dissipation flow channel, and a tertiary heat dissipation flow channel arranged between the primary heat dissipation flow channel and the secondary heat dissipation flow channels. The tertiary heat dissipation flow channel is in the shape of a leaf vein and is in communication with the primary heat dissipation flow channel and the secondary heat dissipation flow channels. The bionic lotus leaf microstructure inner wall modification reduces the heat exchange thermal resistance and flow resistance, and the hydrophobicity of the microstructure enables the fluid to flow more quickly, thereby enhancing the capillary action of the tertiary heat dissipation flow channel and indirectly improving the heat dissipation performance of the heat dissipation flow channels.

[0003] However, in the existing heat dissipation structure, the internal transmission stability is poor due to the internal microstructure design, and the local heat source cannot be effectively dissipated. Therefore, it is necessary to improve the structure of the existing heat dissipation components. SUMMARY

[0004] To solve the above problems, the bionic micro-channel structure is combined with the micro-flow channel with specific parameters to simulate the efficient material transport system in the biological body, optimize the flow uniformity of the cooling liquid, reduce the generation of local hot spots, and improve the overall heat dissipation performance of the bionic micro-channel liquid cooling heat dissipation structure and the preparation method thereof.

[0005] The technical solution adopted by the present application is as follows: a bionic micro-channel liquid cooling heat dissipation structure, comprising a liquid cooling plate main body, a turbulent flow generating assembly, and a gradient heat sink composite layer. The liquid cooling plate main body is internally provided with a fractal bionic micro-flow channel. The fractal bionic micro-flow channel comprises a main channel and at least four levels of branch channels, wherein the last level of branch channels is distributed in a logarithmic spiral line. The turbulent flow generating assembly is composed of staggered triangular prisms and hemispherical pit arrays. The inclination angle of the triangular prisms is 25°-55°. The gradient heat sink composite layer comprises a copper composite substrate containing diamonds and a surface micro-nano structure. The surface micro-nano structure is a conical nano-pillar array with a height of 20-50 μm.

[0006] Further improvement of the above scheme is that the gradient heat sink composite layer is covered on the fractal biomimetic micro-channel by physical vapor deposition process, and the gradient heat sink composite layer is used to conduct the chip heat to the cooling liquid; the turbulence generating assembly forms triangular prisms and hemispherical pit arrays on the surface of the gradient heat sink composite layer by laser micro-texture processing technology.

[0007] Further improvement of the above scheme is that the hydraulic diameter of the micro-channel is 0.5-1.2 mm, the length-diameter ratio is >50, and the heat dissipation power density is ≥150 W / cm².

[0008] Further improvement of the above scheme is that the bifurcation angle of the branch channel is 70°-110°, and the cross-sectional area of the adjacent level channel gradually attenuates.

[0009] Further improvement of the above scheme is that the height of the triangular prism is 1 / 4-1 / 2 of the height of the fractal biomimetic micro-channel, the distance between adjacent prisms is 1.2-2.0 times the height of the prism, and the arrangement density of the hemispherical pit array is 50-200 / cm².

[0010] Further improvement of the above scheme is that the copper composite substrate comprises a 50-100 μm thick copper base layer, a 30-50 μm transition layer, and a 10-30 μm diamond layer, and the transition layer is a copper and diamond gradient composite material.

[0011] Further improvement of the above scheme is that it further comprises a cyclone inlet and a vortex prevention outlet, the cyclone inlet is provided with a spiral guide vane, the lift angle of the spiral guide vane is 15°-30°, and the vortex prevention outlet is provided with a gradually expanding vortex elimination chamber and staggered baffles.

[0012] Further improvement of the above scheme is that the liquid cooling plate body is provided with a plurality of optical fiber temperature sensors, and the plurality of optical fiber temperature sensors are arrayed on the liquid cooling plate body, and the distance between adjacent optical fiber temperature sensors is 2-5 mm.

[0013] Further improvement of the above scheme is that the inner surface of the fractal biomimetic micro-channel is provided with a hydrophobic zone and a hydrophilic zone, the hydrophobic zone and the hydrophilic zone are alternately arranged, the contact angle of the hydrophobic zone is >150°, the contact angle of the hydrophilic zone is <30°, and the alternating period is 3-8 mm.

[0014] Further improvement of the above scheme is that the cross section of the branch channel is a gradually changing rectangle, the width attenuation rate along the flow direction is 0.5-1.2% / mm, and the depth increase rate is 0.3-0.8% / mm.

[0015] Further improvement of the above scheme is that the liquid cooling plate body adopts a chromium-zirconium-copper alloy substrate, and the outer surface is provided with a plasma nitriding treatment layer with a thickness of 10-30 μm and a hardness ≥800 HV.

[0016] A method for preparing a biomimetic microchannel liquid cooling heat dissipation structure, the method comprising the following steps:

[0017] Step S1, using selective laser melting forming liquid cooling plate main body, laser power 200~400W, scanning speed 800~1200mm / s, layer thickness 20~50μm, forming fractal biomimetic microchannel surface roughness Ra≤3.2μm;

[0018] Step S2, etching turbulence generating components in the fractal biomimetic microchannel inner wall by micro electrical discharge machining, pulse width 10~50μs, current intensity 3~8A, machining depth 0.1~0.3mm;

[0019] Step S3, using magnetron sputtering deposition gradient heat sink composite layer, first sputtering 200~500nm titanium bonding layer, then depositing 50μm copper layer, finally depositing diamond layer, sputtering power density 8~12W / cm², substrate temperature 400~600℃;

[0020] Step S4, vacuum diffusion welding packaging, welding pressure 10~20MPa, temperature 750~800℃ for 2~4h, vacuum degree ≤5×10⁻³Pa;

[0021] Step S5, implementing micro-arc oxidation surface treatment, electrolyte containing sodium silicate 10~15g / L, voltage 300~450V, treatment time 10~30min, generating 20~50μm ceramic layer;

[0022] Step S6, optimizing flow channel parameters by particle image velocimetry technology, adjusting the spiral angle of branch channel to 20°~40°, so that the local Nusselt number Nu is improved by 15~25%.

[0023] The present application has the following advantages:

[0024] Compared with the existing heat dissipation structure, the unique design of the fractal bionic micro-channel brings efficient cooling liquid distribution. The setting of the main channel and at least four levels of branch channels, especially the logarithmic spiral distribution of the last level of branch channels, greatly increases the uniformity and coverage of the cooling liquid flow in the liquid cooling plate body. Compared with the traditional flow channel, the fractal structure enables the cooling liquid to reach each heat generating area more quickly and comprehensively, effectively reducing the generation of local hot spots and improving the overall heat dissipation efficiency. Moreover, the fractal structure increases the contact area of the cooling liquid and the inner wall of the liquid cooling plate body, strengthens the convective heat transfer, and further improves the heat dissipation performance. The staggered triangular prisms and hemispherical pit arrays of the turbulence generating assembly are composed, and the inclination angle of the triangular prisms is between 25° ~ 55°, which can effectively disturb the flow state of the cooling liquid and promote the formation of turbulence. The generation of turbulence breaks the limitation of the cooling liquid boundary layer, enhances the mixing and heat exchange inside the cooling liquid, and significantly improves the convective heat transfer coefficient, thereby improving the heat dissipation effect. The specific structure and angle setting can promote turbulence while ensuring the stability of the cooling liquid flow, avoiding excessive pressure loss. The copper composite substrate containing diamond in the gradient heat sink composite layer itself has high thermal conductivity and can quickly transfer heat from the heat source. The tapered nanometer column array micro-nano structure with a surface height of 20 ~ 50 μm greatly increases the surface heat dissipation area, and through the synergistic effect of thermal radiation and convection at the micro-nano scale, the heat dissipation efficiency is further improved, so that the entire liquid cooling heat dissipation structure can more efficiently meet the heat dissipation needs of high-power heat generating equipment.

[0025] The gradient heat sink composite layer is covered on the fractal bionic micro-channel through a physical vapor deposition process, which greatly improves the conduction efficiency of chip heat to the cooling liquid. The gradient heat sink composite layer effectively reduces the thermal resistance by virtue of its unique material properties and structure, enabling heat to be quickly and uniformly transferred from the chip to the cooling liquid, avoiding local overheating of the chip, prolonging the service life of the chip, and ensuring stable operation. The triangular prisms and hemispherical pit arrays formed on the surface of the gradient heat sink composite layer by laser micro-texturing technology serve as turbulence generating components, which can effectively disturb the flow state of the cooling liquid and promote the formation of turbulence. The generation of turbulence increases the contact area and disturbance degree of the cooling liquid and the surface of the gradient heat sink composite layer, improves the convective heat transfer coefficient between the cooling liquid and the heat sink composite layer, and further enhances the heat dissipation effect.

[0026] The present application greatly increases the contact area of the cooling liquid and the micro-channel wall surface by matching a smaller hydraulic diameter with a larger length-diameter ratio, strengthens the convective heat transfer process between the cooling liquid and the heat dissipation structure, and the heat exchange is more sufficient and efficient. The high heat dissipation power density indicates that the structure can quickly dissipate a large amount of heat per unit area, which can effectively cope with the high heat generated by high-power equipment during operation and ensure the stable operation of the equipment in a suitable temperature environment. The combination of the bionic micro-channel structure and the micro-channel with specific parameters simulates the efficient material transport system in the biological body, optimizes the flow uniformity of the cooling liquid, reduces the generation of local hot spots, and improves the overall heat dissipation performance.

[0027] The method for preparing the bionic micro-channel liquid cooling heat dissipation structure precisely controls the laser power, scanning speed and layer thickness and the like in the selective laser melting forming of the liquid cooling plate main body link to ensure that the surface roughness of the formed fractal bionic micro-channel is low, which provides a good foundation for the smooth flow of the subsequent fluid in the micro-channel and effectively reduces the flow resistance. The micro-EDM etching turbulence generating assembly can form turbulence in the fluid in the micro-channel under specific pulse width, current intensity and processing depth, greatly enhancing the heat transfer efficiency between the fluid and the micro-channel wall and improving the heat dissipation performance. The magnetron sputtering deposition of the gradient heat sink composite layer enables the titanium bonding layer, copper layer and diamond layer to be closely combined and have excellent performance. The titanium bonding layer enhances the adhesion between the layers, the copper layer has good thermal conductivity to quickly conduct heat, and the diamond layer further improves the heat dissipation efficiency and wear resistance. The vacuum diffusion welding packaging under suitable pressure, temperature and vacuum degree ensures the sealing and overall strength of the liquid cooling structure, avoids leakage of the cooling liquid and deformation of the structure. The ceramic layer generated by the micro-arc oxidation surface treatment not only improves the corrosion resistance of the liquid cooling structure, but also enhances the surface hardness. Finally, the particle image velocimetry technology is used to optimize the flow channel parameters and adjust the spiral angle of the branch channel, effectively improving the local Nusselt number and significantly enhancing the heat dissipation capacity of the liquid cooling heat dissipation structure, meeting the heat dissipation needs of high-power equipment. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 Figure 1 is a structural schematic diagram of the bionic micro-channel liquid cooling heat dissipation structure according to the present application;

[0029] Figure 2 Figure 2 is a structural schematic diagram of the bionic micro-channel liquid cooling heat dissipation structure according to the present application from another perspective; Figure 1

[0030] Figure 3 Figure 1

[0031] Figure 4 Figure 1 ​​​​enlarged view of A in FIG.

[0032] Figure 5 For Figure 1 structure diagram of the fractal bionic microchannel of the bionic microchannel liquid cooling heat dissipation structure in the application;

[0033] Figure 6 For Figure 1 structure diagram of the turbulence generating assembly of the bionic microchannel liquid cooling heat dissipation structure in the application;

[0034] Figure 7 For Figure 1 structure diagram of the gradient heat sink composite layer of the bionic microchannel liquid cooling heat dissipation structure in the application;

[0035] Figure 8 For Figure 1 structure diagram of the gradient heat sink composite layer of the bionic microchannel liquid cooling heat dissipation structure in the application;

[0036] Figure 9 For Figure 1 structure diagram of the rotational flow inlet of the bionic microchannel liquid cooling heat dissipation structure in the application;

[0037] Figure 10 For Figure 1 structure diagram of the vortex prevention outlet of the bionic microchannel liquid cooling heat dissipation structure in the application;

[0038] Figure 11 Flow diagram of the method for preparing the bionic microchannel liquid cooling heat dissipation structure in the application.

[0039] Legend of reference signs: liquid cooling plate body 1, fractal bionic microchannel 11, main channel 111, branch channel 112, hydrophobic area 113, hydrophilic area 114, optical fiber temperature sensor 12, turbulence generating assembly 2, triangular prism 21, hemispherical pit 22, gradient heat sink composite layer 3, copper composite base 31, micro-nano structure 32, thick copper base layer 33, transition layer 34, diamond layer 35, rotational flow inlet 4, spiral flow guide vane 41, vortex prevention outlet 5, staggered baffle 52. DETAILED DESCRIPTION

[0040] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided so that the disclosure of the present application can be more thoroughly and completely understood.

[0041] It is to be understood that where an element such as a layer, region or substrate is described as being "on" another element, it can be directly on the other element or intervening elements can also be present. Where an element such as a layer, region or substrate is described as being "connected" to another element, it can be directly connected to the other element or intervening elements can also be present.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application.

[0043] As Figures 1-11As shown, in an embodiment of the present application, a kind of based on bionic microchannel liquid cooling heat dissipation structure is related to, including liquid cooling plate main body 1, turbulence generation component 2 and gradient heat sink composite layer 3, the inside of the liquid cooling plate main body 1 is equipped with fractal bionic microchannel 11, the fractal bionic microchannel 11 includes stem channel 111 and at least four levels of branch channel 112, wherein, last branch channel 112 is in logarithmic spiral line distribution;The turbulence generation component 2 is formed by staggered arrangement of triangular prism 21 and hemispherical pit 22 array, the inclination angle of the triangular prism 21 is 25 ° ~ 55 °;The gradient heat sink composite layer 3 includes diamond-containing copper composite matrix 31 and surface micro-nano structure 32, the surface micro-nano structure 32 is the conical nanometer column array of height 20 ~ 50 μm.The present application in fractal bionic microchannel 11, its unique design brings efficient cooling liquid distribution.Stem channel 111 and the setting of at least four levels of branch channel 112, especially last branch channel 112 is in logarithmic spiral line distribution, greatly increases the flow uniformity and coverage range of cooling liquid in the liquid cooling plate main body 1.Compared with traditional flow channel, fractal structure makes cooling liquid more quickly, more fully reach each heat generating area, effectively reduces the generation of local hot spots, improves the overall heat dissipation efficiency.Moreover, fractal structure increases the contact area of cooling liquid and the inner wall of liquid cooling plate main body, strengthens the convection heat transfer, further improves the heat dissipation performance.Turbulence generation component 2 is formed by staggered arrangement of triangular prism 21 and hemispherical pit 22 array, wherein the inclination angle of the triangular prism 21 is between 25 ° ~ 55 °, can effectively disturb the flow state of cooling liquid, promotes it to form turbulence.The generation of turbulence breaks the limitation of cooling liquid boundary layer, enhances the mixing and heat exchange inside cooling liquid, significantly improves the convection heat transfer coefficient, thereby improves the heat dissipation effect.Specific structure and angle setting, while promoting turbulence, can also ensure the stability of cooling liquid flow, avoid the emergence of excessive pressure loss.Gradient heat sink composite layer 3 diamond-containing copper composite matrix 31 itself has high thermal conductivity, can quickly transmit heat from heat source.Out of the surface height of 20 ~ 50 μm conical nanometer column array micro-nano structure, greatly increases the surface heat dissipation area, through the synergistic effect of thermal radiation and convection under micro-nano scale, further improves the heat dissipation efficiency, so that the whole liquid cooling heat dissipation structure can more efficiently cope with the heat dissipation demand of high-power heat generating equipment.

[0044] The gradient heat sink composite layer 3 is covered on the fractal biomimetic microchannel 11 by a physical vapor deposition process, and is used to conduct the chip heat to the cooling liquid; and the turbulence generating assembly 2 is formed by a laser micro-texture machining technology, and the triangular prisms 21 and the hemispherical pit 22 array are formed on the surface of the gradient heat sink composite layer 3. In the embodiment, the gradient heat sink composite layer 3 is covered on the fractal biomimetic microchannel 11 by a physical vapor deposition process, which greatly improves the conduction efficiency of the chip heat to the cooling liquid. The gradient heat sink composite layer 3 effectively reduces the thermal resistance due to its unique material properties and structure, so that the heat can be quickly and uniformly transferred from the chip to the cooling liquid, avoiding local overheating of the chip, prolonging the service life of the chip, and ensuring stable operation. The triangular prisms 21 and the hemispherical pit 22 array formed on the surface of the gradient heat sink composite layer 3 by the laser micro-texture machining technology serve as the turbulence generating assembly 2, which can effectively disturb the flow state of the cooling liquid and promote the formation of turbulence in the cooling liquid. The generation of turbulence increases the contact area and disturbance degree between the cooling liquid and the surface of the gradient heat sink composite layer 3, improves the convective heat transfer coefficient between the cooling liquid and the heat sink composite layer, and further enhances the heat dissipation effect.

[0045] The hydraulic diameter of the microchannel is 0.5-1.2 mm, the length-diameter ratio is greater than 50, and the heat dissipation power density is greater than or equal to 150 W / cm². In the embodiment, the smaller hydraulic diameter is matched with the larger length-diameter ratio, which greatly increases the contact area between the cooling liquid and the microchannel wall, strengthens the convective heat transfer process between the cooling liquid and the heat dissipation structure, and the heat exchange is more sufficient and efficient. The high heat dissipation power density indicates that the structure can quickly dissipate a large amount of heat per unit area, which can effectively cope with the high heat generated by high-power equipment during operation, and ensure that the equipment works stably in a suitable temperature environment. The biomimetic microchannel structure is combined with the microchannel with specific parameters to simulate the efficient material transport system in the biological body, optimize the flow uniformity of the cooling liquid, reduce the generation of local hot spots, and improve the overall heat dissipation performance.

[0046] In the above embodiment, the synergistic heat dissipation effect of the fractal microchannel and the turbulence assembly is tested

[0047] The bifurcation angle of the branch channel 112 is 70°-110°, and the cross-sectional area of the adjacent level channel gradually decreases. In the embodiment, the angle range can effectively guide the flow direction and distribution of the cooling liquid in the channel. When the cooling liquid flows through the bifurcation, the angle makes the cooling liquid be more uniformly distributed to each branch channel 112, avoiding the situation that the local flow is too large or too small, thereby improving the uniformity of the overall heat dissipation efficiency. The cross-sectional area of the adjacent level channel gradually decreases. As the cooling liquid flows in the channel, the gradual decrease of the cross-sectional area can increase the flow rate of the cooling liquid. The increase of the flow rate helps to enhance the convective heat transfer coefficient between the cooling liquid and the channel wall, and can more efficiently transfer the heat from the heat source to the cooling liquid.

[0048] The height of the triangular prism 21 is 1 / 4-1 / 2 of the height of the fractal biomimetic microchannel 11, the ratio of the distance between adjacent prisms to the height of the prism is 1.2-2.0, and the arrangement density of the array of hemispherical pits 22 is 50-200 pieces / cm2. In this embodiment, the specific ratio of the height of the triangular prism 21 to the height of the fractal biomimetic microchannel 11, i.e. the height of the triangular prism 21 is 1 / 4-1 / 2 of the height of the fractal biomimetic microchannel 11, is of great significance for optimizing the heat dissipation performance. This ratio can effectively guide the cooling liquid to form a suitable flow state in the microchannel, enhance the contact and heat exchange efficiency between the cooling liquid and the flow channel wall. The ratio of the distance between adjacent prisms to the height of the prism is in the range of 1.2-2.0, which can adjust the flow rate and flow direction of the cooling liquid, promote the uniform distribution of the cooling liquid in the entire heat dissipation area, and avoid local overheating phenomenon. The arrangement density of the array of hemispherical pits 22 is 50-200 pieces / cm2, which further increases the contact area between the cooling liquid and the heat dissipation surface, strengthens the turbulence degree of the cooling liquid, and effectively improves the heat dissipation coefficient of the heat dissipation structure.

[0049] The copper composite substrate 31 comprises a 50-100 μm thick copper base layer 33, a 30-50 μm transition layer 34, and a 10-30 μm diamond layer 35. The transition layer 34 is a copper and diamond gradient composite material. In this embodiment, the 50-100 μm thick copper base layer can efficiently collect and preliminarily conduct heat due to its good electrical conductivity and thermal conductivity, thereby laying a solid heat dissipation foundation for the entire heat dissipation system. The 30-50 μm transition layer 34 as a copper and diamond gradient composite material plays a key role in connection and optimization. It effectively alleviates the interface thermal resistance problem between the copper base layer and the diamond layer 35 due to the difference in material properties, making heat transfer more smooth and efficient, and reducing the heat dissipation resistance caused by thermal resistance mutation. The 10-30 μm diamond layer 35 can quickly dissipate heat due to its ultra-high thermal conductivity, thereby significantly improving the heat dissipation efficiency.

[0050] Referring to Figures 9-10As shown, the liquid cooling plate body 1 is provided with a spiral inlet 4 and a vortex prevention outlet 5. The spiral inlet 4 is provided with a spiral vane 41 with an angle of 15°-30°. The vortex prevention outlet 5 is provided with a gradually expanding vortex elimination chamber 51 and staggered baffles 52. In the embodiment, the spiral vane 41 of the spiral inlet 4 has an angle of 15°-30°, which can make the cooling liquid enter the system in a specific spiral manner. On the one hand, the spiral flow can enhance the contact and friction between the cooling liquid and the microchannel wall surface, greatly improve the turbulent degree of the cooling liquid, and thus improve the convective heat transfer coefficient and significantly enhance the heat dissipation effect. On the other hand, such orderly spiral flow helps to stabilize the flow state of the cooling liquid, reduce the flow dead zone and local overheating phenomenon. The gradually expanding vortex elimination chamber 51 and staggered baffles 52 at the vortex prevention outlet 5 can effectively eliminate the vortex generated when the cooling liquid flows out. The gradually expanding structure can reduce the speed of the fluid, reduce the kinetic energy of the fluid, and inhibit the generation and development of the vortex. The staggered baffles 52 further disturb the shape of the vortex, so that the vortex dissipates, ensuring that the cooling liquid flows out smoothly and avoiding problems such as pressure fluctuation and uneven flow caused by vortex.

[0051] The liquid cooling plate body 1 is provided with a plurality of optical fiber temperature sensors 12, which are arrayed on the liquid cooling plate body 1 with a spacing of 2-5 mm between adjacent optical fiber temperature sensors 12. In the embodiment, the temperature distribution on the surface of the liquid cooling plate body can be accurately sensed. Due to the small spacing between the sensors, the temperature change in a small area can be captured, providing detailed and comprehensive data support for monitoring the heat dissipation effect of the cooling liquid in the bionic microchannel. It is helpful to timely find abnormal heat dissipation points. During the operation of the liquid cooling system, if the temperature abnormally rises due to poor heat dissipation in a local area, the closely arranged sensors can quickly sense and feedback so that the technical personnel can timely adjust the system parameters or troubleshoot the fault. By obtaining a large amount of and dense temperature data, the design of the bionic microchannel can be further optimized. Based on these temperature information, the structure of the microchannel, the flow rate of the cooling liquid and other key parameters can be improved.

[0052] In the above embodiment, the performance of the gradient heat sink layer and the flow guide structure is verified

[0053] The inner surface of the fractal bionic micro-channel 11 is provided with hydrophobic regions 113 and hydrophilic regions 114, which are arranged alternately, the contact angle of the hydrophobic region 113 is > 150°, the contact angle of the hydrophilic region 114 is < 30°, and the alternating period is 3-8 mm. In this embodiment, the contact angle of the hydrophobic region 113 is > 150°, which shows strong hydrophobicity, can effectively prevent the adhesion and spreading of the liquid in this region, and promote the liquid to quickly converge into droplets, forming a favorable flow form. The contact angle of the hydrophilic region 114 is < 30°, which shows good hydrophilicity and can quickly guide the directional flow of the liquid. The alternating period is set to 3-8 mm, which makes the liquid in the micro-channel maintain a proper flow rhythm, avoids uneven distribution of the liquid due to too long period, and prevents flow disorder caused by too short period. This alternating arrangement greatly optimizes the flow state of the cooling liquid in the micro-channel, enhances the contact and heat exchange efficiency between the cooling liquid and the micro-channel wall, and thus improves the heat dissipation performance of the entire liquid cooling heat dissipation structure, ensuring the efficient and stable operation of the system. Effectively reduce the high heat generated during equipment operation, ensure the equipment to work continuously and stably in a suitable temperature environment, reduce the performance decline, component aging and other problems caused by overheating, and prolong the service life of the equipment.

[0054] The cross section of the branch channel 112 is a gradually changing rectangle, the width attenuation rate along the flow direction is 0.5-1.2% / mm, and the depth increase rate is 0.3-0.8% / mm. In this embodiment, the width attenuation rate along the flow direction is controlled to be 0.5-1.2% / mm, which can effectively adjust the flow rate and pressure distribution of the fluid in the channel. With the attenuation of the width, the fluid velocity changes accordingly, which promotes the contact between the cooling liquid and the channel wall, enhances the convective heat transfer coefficient, and improves the heat dissipation efficiency. The depth increase rate is 0.3-0.8% / mm, which increases the storage amount of the cooling liquid and prolongs the residence time of the cooling liquid in the channel, which is beneficial to absorb more heat. This gradual design can also avoid local overheating, making the heat distribution more uniform, and effectively reducing the thermal resistance.

[0055] The liquid cooling plate body adopts a chromium-zirconium-copper alloy substrate, and the outer surface is provided with a plasma nitriding treatment layer with a thickness of 10-30 μm and a hardness of ≥800 HV. In this embodiment, the chromium-zirconium-copper alloy substrate has good thermal conductivity, which lays a solid foundation for efficient heat dissipation and can quickly conduct heat from the heat source to the liquid cooling plate body. The outer surface of the plasma nitriding treatment layer with a thickness of 10-30 μm plays a key role, and the hardness of ≥800 HV greatly improves the wear resistance and corrosion resistance of the liquid cooling plate body, prolongs its service life, and reduces the risk of performance decline caused by wear or corrosion. This treatment enables the liquid cooling plate body to maintain stable structure and performance in complex and harsh working environments.

[0056] In the above embodiment, the chromium-zirconium-copper alloy substrate has a Cu content of ≥99.2 wt%, a Cr content of 0.15-0.25 wt%, a Zr content of 0.08-0.12 wt%, and a total content of impurities of ≤0.05 wt% (including O ≤0.003 wt%, S ≤0.005 wt%).

[0057] The transition layer gradient composite material has a diamond volume fraction gradient that linearly increases from 0% in the copper base layer to 85% in the diamond layer, and a diamond grain D50 particle size that is 5 μm at the bottom of the transition layer and 25 μm at the top (gradient change).

[0058] The plasma nitriding treatment layer contains ε-Fe3N phase (60-75%) and γ'-Fe4N phase (25-40%), and has a surface nitrogen concentration gradient of ≥12 at% in the surface layer and ≤3 at% at the substrate interface.

[0059] In the above embodiment, the surface characteristics and the material strengthening effect are compared.

[0060] Reference is made to Figures 1-11As shown, a method for preparing a biomimetic microchannel liquid cooling heat dissipation structure, the method comprising the following steps: step S1, using selective laser melting forming a liquid cooling plate main body, laser power 200-400 W, scanning speed 800-1200 mm / s, layer thickness 20-50 μm, surface roughness Ra≤3.2 μm of the formed fractal biomimetic microchannel 11; step S2, etching a turbulence generating component 2 on the inner wall of the fractal biomimetic microchannel 11 by micro electro discharge machining, pulse width 10-50 μs, current intensity 3-8 A, machining depth 0.1-0.3 mm; step S3, using magnetron sputtering to deposit a gradient heat sink composite layer 3, first sputtering a 200-500 nm titanium bonding layer, then depositing a 50 μm copper layer, and finally depositing a diamond layer 35, sputtering power density 8-12 W / cm2, substrate temperature 400-600 °C; step S4, vacuum diffusion welding packaging, welding pressure 10-20 MPa, temperature 750-800 °C for 2-4 h, vacuum degree ≤5×10-3 Pa; step S5, micro-arc oxidation surface treatment, electrolyte containing sodium silicate 10-15 g / L, voltage 300-450 V, treatment time 10-30 min, generating a 20-50 μm ceramic layer; step S6, optimizing the flow channel parameters by particle image velocimetry technology, adjusting the spiral angle of the branch channel 112 to 20-40°, and improving the local Nusselt number Nu by 15-25%. In this embodiment, in the process of selective laser melting forming a liquid cooling plate main body, the laser power, scanning speed and layer thickness are accurately controlled to ensure that the surface roughness of the formed fractal biomimetic microchannel 11 is low, which provides a good foundation for the smooth flow of the subsequent fluid in the microchannel and effectively reduces the flow resistance. By etching the turbulence generating component 2 by micro electro discharge machining, under a certain pulse width, current intensity and machining depth, the fluid can form turbulence in the microchannel, greatly enhancing the heat transfer efficiency between the fluid and the microchannel wall and improving the heat dissipation performance. Magnetron sputtering deposition of the gradient heat sink composite layer 3, reasonable sputtering power density and substrate temperature control, make the titanium bonding layer, copper layer and diamond layer 35 tightly combined and excellent performance. The titanium bonding layer enhances the adhesion between the layers, the copper layer has good thermal conductivity to quickly conduct heat, and the diamond layer 35 further improves the heat dissipation efficiency and wear resistance. Vacuum diffusion welding packaging under suitable pressure, temperature and vacuum degree conditions ensures the sealing and overall strength of the liquid cooling structure, avoiding cooling liquid leakage and structure deformation. The ceramic layer generated by micro-arc oxidation surface treatment not only improves the corrosion resistance of the liquid cooling structure, but also enhances the surface hardness. Finally, by optimizing the flow channel parameters by particle image velocimetry technology, adjusting the spiral angle of the branch channel 112, the local Nusselt number is effectively improved, and the heat dissipation capacity of the liquid cooling heat dissipation structure is significantly enhanced, meeting the heat dissipation needs of high-power equipment.

[0061] In the above embodiment, in the step of magnetron sputtering deposition, the copper layer is doped with 0.5-1.2wt% nano Al2O3 particles (particle size 50-80nm) to improve the anti-creep performance.

[0062] In the step of vacuum diffusion welding, Ag-Cu-Ti active filler (Ag72Cu26Ti2 wt%) is used, and the thickness of the brazing seam is controlled to be 10-15μm.

[0063] In the step of micro-arc oxidation treatment, nano ZrO2 (2-5g / L) is added to the electrolyte to generate Zr-doped ceramic layer to improve the thermal shock resistance.

[0064] The above embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as the limitation of the patent scope of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A biomimetic microchannel-based liquid cooling heat dissipation structure, characterized in that: Comprising A liquid cooling plate body, which is internally provided with a fractal bionic micro-channel, the fractal bionic micro-channel comprises a main channel and at least four levels of branch channels, wherein the last level of branch channels is distributed in a logarithmic spiral line; A turbulence generating assembly composed of staggered triangular prisms and hemispherical pit arrays, the inclination angle of the triangular prisms is 25°-55°; A gradient heat sink composite layer, which comprises a diamond-containing copper composite substrate and a surface micro-nano structure, the surface micro-nano structure is a tapered nano-pillar array with a height of 20-50 μm; The gradient heat sink composite layer is covered on the fractal bionic micro-channel by physical vapor deposition process, and the gradient heat sink composite layer is used to conduct the heat of the chip to the cooling liquid; The turbulence generating assembly is formed on the surface of the gradient heat sink composite layer by laser micro-texturing technology, and the triangular prisms and hemispherical pit arrays are formed; The hydraulic diameter of the micro-channel is 0.5-1.2 mm, the length-diameter ratio is >50, and the heat dissipation power density is ≥150 W / cm².

2. The bionic micro-channel liquid cooling heat dissipation structure according to claim 1, characterized in that: The bifurcation angle of the branch channel is 70°-110°, and the cross-sectional area of the adjacent level channel gradually decreases.

3. The bionic micro-channel liquid cooling heat dissipation structure according to claim 1, characterized in that: The height of the triangular prism is 1 / 4-1 / 2 of the height of the fractal bionic micro-channel, the ratio of the distance between adjacent prisms to the height of the prism is 1.2-2.0, and the arrangement density of the hemispherical pit array is 50-200 / cm².

4. The bionic micro-channel liquid cooling heat dissipation structure according to claim 1, characterized in that: The copper composite substrate comprises a 50-100 μm thick copper base layer, a 30-50 μm transition layer, and a 10-30 μm diamond layer, and the transition layer is a copper and diamond gradient composite material.

5. The bionic micro-channel liquid cooling heat dissipation structure according to claim 1, characterized in that: It also includes a cyclone inlet and a vortex prevention outlet, the cyclone inlet is provided with a spiral guide vane, the lift angle of the spiral guide vane is 15°-30°, and the vortex prevention outlet is provided with a gradually expanding vortex elimination chamber and staggered baffles.

6. The bionic micro-channel liquid cooling heat dissipation structure according to claim 1, characterized in that: The liquid cooling plate body is provided with a plurality of optical fiber temperature sensors, and a plurality of optical fiber temperature sensor arrays are distributed on the liquid cooling plate body, and the distance between adjacent optical fiber temperature sensors is 2-5 mm.

7. The bionic micro-channel liquid cooling heat dissipation structure according to claim 1, characterized in that: The inner surface of the fractal bionic micro-channel is provided with hydrophobic and hydrophilic regions, the hydrophobic and hydrophilic regions are alternately arranged, the contact angle of the hydrophobic region is >150°, the contact angle of the hydrophilic region is <30°, and the alternating period is 3-8 mm.

8. The bionic micro-channel liquid cooling heat dissipation structure according to claim 1, characterized in that: The cross section of the branch channel is a gradually changing rectangle, the width attenuation rate along the flow direction is 0.5-1.2% / mm, and the depth increase rate is 0.3-0.8% / mm.

9. The bionic micro-channel liquid cooling heat dissipation structure according to claim 1, characterized in that: The liquid cooling plate body adopts a chromium-zirconium-copper alloy substrate, and the outer surface is provided with a plasma nitrided layer with a thickness of 10-30 μm and a hardness of ≥800 HV.

10. A method for preparing the biomimicry microchannel liquid cooling heat dissipation structure according to any one of claims 1-9, characterized in that: The method comprises the following steps: Step S1, using selective laser melting to form a liquid cooling plate body substrate, laser power 200-400 W, scanning speed 800-1200 mm / s, layer thickness 20-50 μm, and the surface roughness of the formed fractal bionic micro-channel Ra≤3.2 μm; Step S2, etching a turbulence generating assembly on the inner wall of the fractal bionic micro-channel by micro electrical discharge machining, pulse width 10-50 μs, current intensity 3-8 A, and machining depth 0.1-0.3 mm; Step S3, a gradient heat sink composite layer is deposited by magnetron sputtering, a 200-500 nm titanium adhesive layer is first sputtered, then a 50 μm copper layer is deposited, and finally a diamond layer is deposited, the sputtering power density is 8-12 W / cm², and the substrate temperature is 400-600 ℃; Step S4, vacuum diffusion welding packaging is performed, the welding pressure is 10-20 MPa, the temperature is 750-800 ℃ and is maintained for 2-4 h, and the vacuum degree is ≤5×10⁻³ Pa; Step S5, micro-arc oxidation surface treatment is implemented, the electrolyte contains 10-15 g / L of sodium silicate, the voltage is 300-450 V, the treatment time is 10-30 min, and a 20-50 μm ceramic layer is generated; Step S6, the flow channel parameters are optimized by the particle image velocimetry technology, the spiral angle of the branch channel is adjusted to 20°-40°, and the local Nusselt number Nu is increased by 15-25%.

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