Liquid cooling heat dissipation structure based on bionic microchannel and preparation method

Abstract

The invention relates to the technical field of liquid cooling heat dissipation, in particular to a liquid cooling heat dissipation structure based on a bionic microchannel and a preparation method of the liquid cooling heat dissipation structure based on the bionic microchannel, and the liquid cooling heat dissipation structure comprises a liquid cooling plate main body, a turbulent flow generation assembly and a gradient heat sink composite layer, the fractal bionic micro-channel comprises a main channel and at least four stages of branch channels, and the last-stage branch channel is distributed in a logarithmic spiral line mode; the turbulent flow generation assembly is composed of triangular prisms and hemispherical pit arrays which are arranged in a staggered mode. The gradient heat sink composite layer comprises a diamond-containing copper composite matrix and a surface micro-nano structure. The bionic micro-channel structure is combined with the micro-channel with specific parameters, an efficient substance transmission system in a living body is simulated, the flowing uniformity of cooling liquid is optimized, generation of local hot spots is reduced, and the overall heat dissipation performance is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid cooling heat dissipation, and particularly to a bionic microchannel liquid cooling heat dissipation structure and a preparation method thereof. Background Art

[0002] In the prior art, Chinese Patent Application No.: CN202310217469.X discloses a microchannel heat dissipation structure and a heat dissipation device with a bionic structure, which relates to the technical field of heat dissipation of electronic components. It includes: a primary heat dissipation channel, and a plurality of secondary heat dissipation channels are connected to the primary heat dissipation channel, and the secondary heat dissipation channels are mutually communicated with the primary heat dissipation channel; a tertiary heat dissipation channel is arranged between the primary heat dissipation channel and the secondary heat dissipation channel. The tertiary heat dissipation channel is integrally in the shape of an imitation leaf vein, and the tertiary heat dissipation channel is respectively communicated with the primary heat dissipation channel and the secondary heat dissipation channel. The inner wall of the bionic lotus leaf microstructure is modified, reducing the heat transfer resistance and flow resistance. The hydrophobicity of the microstructure enables the fluid to flow more rapidly, enhancing the capillary action of the tertiary heat dissipation channel and indirectly improving the heat dissipation performance of each heat dissipation channel.

[0003] However, in the existing heat dissipation structure, due to the internal microstructural design, the internal transmission stability is poor, and it cannot ensure heat dissipation of local heat sources. Therefore, it is necessary to make new improvements to the structure of the existing heat dissipation components. Summary of the Invention

[0004] To solve the above problems, the present invention combines a bionic microchannel structure with microchannels of specific parameters, simulates an efficient substance transport system in a living organism, optimizes the flow uniformity of the coolant, reduces the generation of local hot spots, and improves the overall heat dissipation performance of a bionic microchannel liquid cooling heat dissipation structure and a preparation method thereof.

[0005] The technical solution adopted by the present invention is: a bionic microchannel liquid cooling heat dissipation structure, including a liquid cooling plate main body, a turbulent flow generation component, and a gradient heat sink composite layer. The liquid cooling plate main body is internally provided with a fractal bionic microchannel, and the fractal bionic microchannel includes a main channel and at least four levels of branch channels. Among them, the last-level branch channels are distributed in a logarithmic spiral; the turbulent flow generation component is composed of a staggered array of triangular prisms and hemispherical pits, and the inclination angle of the triangular prisms is 25° - 55°; the gradient heat sink composite layer includes a copper composite matrix containing diamond and a surface micro-nano structure, and the surface micro-nano structure is an array of conical nano-columns with a height of 20 - 50 μm.

[0006] A further improvement to the above solution is that the gradient heat sink composite layer is covered on the fractal bionic microchannel through a physical vapor deposition process, and the gradient heat sink composite layer is used to conduct the heat of the chip to the coolant; the turbulent flow generating component forms an array of triangular prisms and hemispherical pits on the surface of the gradient heat sink composite layer through laser micro-texturing processing technology.

[0007] A further improvement to the above solution is that the hydraulic diameter of the microchannel is 0.5 - 1.2 mm, the aspect ratio > 50, and the heat dissipation power density ≥ 150 W / cm².

[0008] A further improvement to the above solution is that the bifurcation angle of the branch channel is 70° - 110°, and the cross-sectional area of adjacent hierarchical channels gradually decreases.

[0009] A further improvement to the above solution is that the height of the triangular prism is 1 / 4 - 1 / 2 of the height of the fractal bionic microchannel, the ratio of the spacing between adjacent prisms to the prism height is 1.2 - 2.0, and the arrangement density of the hemispherical pit array is 50 - 200 pieces / cm².

[0010] A further improvement to the above solution is that the copper composite substrate includes 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] A further improvement to the above solution is that it further includes a swirl inlet and an anti-vortex outlet. The swirl inlet is provided with spiral guide vanes, the lift angle of the spiral guide vanes is 15° - 30°, and the anti-vortex outlet is provided with a gradually expanding anti-vortex chamber and staggered baffles.

[0012] A further improvement to the above solution is that the liquid cooling plate body is provided with a plurality of fiber optic temperature sensors, and the plurality of fiber optic temperature sensors are arranged in an array on the liquid cooling plate body, and the spacing between adjacent fiber optic temperature sensors is 2 - 5 mm.

[0013] A further improvement to the above solution is that the inner surface of the fractal bionic microchannel is provided with a hydrophobic area and a hydrophilic area, the hydrophobic area and the hydrophilic area are arranged alternately, the contact angle of the hydrophobic area > 150°, the contact angle of the hydrophilic area < 30°, and the alternating period is 3 - 8 mm.

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

[0015] A further improvement to the above solution is that the liquid cooling plate body is made of a chromium zirconium copper alloy substrate, the thickness of the plasma nitriding treatment layer on its outer surface is 10 - 30 μm, and the hardness ≥ 800 HV.

[0016] A method for preparing a bionic microchannel liquid cooling heat dissipation structure, the method comprising the following steps: Step S1, using selective laser melting to form the main body matrix of the liquid cooling plate, with a laser power of 200 - 400 W, a scanning speed of 800 - 1200 mm / s, a layer thickness of 20 - 50 μm, and the surface roughness Ra of the formed fractal bionic microchannel ≤ 3.2 μm; Step S2, etching the turbulent flow generating components on the inner wall of the fractal bionic microchannel by micro - electro - discharge machining, with a pulse width of 10 - 50 μs, a current intensity of 3 - 8 A, and a machining depth of 0.1 - 0.3 mm; Step S3, using magnetron sputtering to deposit a gradient heat sink composite layer, first sputtering a 200 - 500 nm titanium bonding layer, then depositing a 50 μm copper layer, and finally depositing a diamond layer, with a sputtering power density of 8 - 12 W / cm² and a substrate temperature of 400 - 600 °C; Step S4, performing vacuum diffusion welding and packaging, with a welding pressure of 10 - 20 MPa, maintaining the temperature at 750 - 800 °C for 2 - 4 h, and a vacuum degree ≤ 5×10⁻³ Pa; Step S5, implementing micro - arc oxidation surface treatment, with the electrolyte containing 10 - 15 g / L of sodium silicate, a voltage of 300 - 450 V, a treatment time of 10 - 30 min, and generating a 20 - 50 μm ceramic layer; Step S6, optimizing the flow channel parameters through particle image velocimetry technology, adjusting the spiral angle of the branch channel to 20° - 40°, and increasing the local Nusselt number Nu by 15 - 25%.

[0017] The beneficial effects of the present invention are: Compared with the existing heat dissipation structures, in terms of the fractal bionic microchannels, the unique design of the present invention brings about efficient coolant distribution. The arrangement of the main channel and at least four levels of branch channels, especially the logarithmic spiral distribution of the last-level branch channels, greatly increases the flow uniformity and coverage range of the coolant within the liquid-cooling plate body. Compared with traditional channels, the fractal structure enables the coolant 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 between the coolant and the inner wall of the liquid-cooling plate body, enhancing the convective heat transfer and further improving the heat dissipation performance. The turbulent flow generating component is composed of an array of triangular prisms and hemispherical pits arranged in a staggered manner, where the inclination angle of the triangular prisms is between 25° and 55°, which can effectively disrupt the flow state of the coolant and prompt it to form turbulent flow. The generation of turbulent flow breaks the limitation of the coolant boundary layer, enhances the mixing and heat exchange within the coolant, significantly increases the convective heat transfer coefficient, and thus improves the heat dissipation effect. The specific structure and angle settings can ensure the stability of the coolant flow while promoting turbulent flow, avoiding excessive pressure loss. The gradient heat sink composite layer with a diamond-containing copper composite matrix itself has high thermal conductivity and can quickly transfer heat from the heat source. The micro-nano structure of the conical nano-column array with a surface height of 20 - 50μm greatly increases the surface heat dissipation area, and through the synergistic effect of thermal radiation and convection at the micro-nano scale, further improves the heat dissipation efficiency, enabling the entire liquid-cooling heat dissipation structure to more efficiently meet the heat dissipation requirements of high-power heat-generating devices.

[0018] The present invention covers the gradient heat sink composite layer on the fractal bionic microchannels through physical vapor deposition technology, greatly improving the heat conduction efficiency from the chip to the coolant. Relying on its unique material properties and structure, the gradient heat sink composite layer effectively reduces the thermal resistance, enabling heat to be quickly and evenly transferred from the chip to the coolant, avoiding local overheating of the chip, extending the service life of the chip, and ensuring its stable operation. The array of triangular prisms and hemispherical pits formed on the surface of the gradient heat sink composite layer by laser micro-texturing processing technology, as the turbulent flow generating component, can effectively disrupt the flow state of the coolant and prompt the coolant to form turbulent flow. The generation of turbulent flow increases the contact area and disturbance degree between the coolant and the surface of the gradient heat sink composite layer, improves the convective heat transfer coefficient between the coolant and the heat sink composite layer, and further enhances the heat dissipation effect.

[0019] By combining a smaller hydraulic diameter with a larger aspect ratio, the present invention significantly increases the contact area between the coolant and the microchannel wall, enhancing the convective heat transfer process between the coolant and the heat dissipation structure, making heat exchange more complete and efficient. The high heat dissipation power density indicates that the structure can quickly dissipate a large amount of heat per unit area, effectively addressing the high heat generated by high-power equipment during operation and ensuring stable operation of the equipment under suitable temperature conditions. The biomimetic microchannel structure is combined with microchannels of specific parameters to simulate the efficient material transfer system within the organism, optimizing the flow uniformity of the coolant, reducing the generation of local hot spots, and improving overall heat dissipation performance.

[0020] This method for fabricating a biomimetic microchannel liquid-cooling heat dissipation structure involves selective laser melting to form the main body of the liquid cooling plate. Precisely controlling parameters such as laser power, scanning speed, and layer thickness ensures low surface roughness of the resulting fractal biomimetic microchannels, ensuring smooth fluid flow within the microchannels and effectively reducing flow resistance. By using micro-EDM to etch a turbulence-generating component, under specific pulse widths, current intensities, and machining depths, turbulence is generated within the microchannels, significantly enhancing heat transfer efficiency between the fluid and the microchannel walls and improving heat dissipation performance. Magnetron sputtering deposits a gradient heat sink composite layer. Optimized sputtering power density and substrate temperature control ensure a tight bond between the titanium bonding layer, copper layer, and diamond layer, resulting in excellent performance. The titanium bonding layer enhances interlayer adhesion, the copper layer's excellent thermal conductivity allows for rapid heat transfer, and the diamond layer further improves heat dissipation efficiency and wear resistance. Vacuum diffusion welding, performed under appropriate pressure, temperature, and vacuum conditions, ensures the sealing and overall strength of the liquid cooling structure, preventing coolant leakage and structural 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 its surface hardness. Finally, particle image velocimetry was used to optimize flow channel parameters and adjust the helix angle of the branch channels, effectively increasing the local Nusselt number and significantly enhancing the heat dissipation capacity of the liquid cooling structure, meeting the heat dissipation requirements of high-power devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the structure of the bionic microchannel liquid cooling and heat dissipation structure of the present invention; Figure 2 for Figure 1 A schematic diagram of the structure based on the bionic microchannel liquid cooling heat dissipation structure from another perspective; Figure 3 for Figure 1 A schematic diagram of the structure based on the bionic microchannel liquid cooling heat dissipation structure from another perspective; Figure 4 for Figure 1 A is an enlarged schematic diagram; Figure 5 forFigure 1 Schematic diagram of the fractal bionic microchannel based on the bionic microchannel liquid cooling heat dissipation structure; Figure 6 is Figure 1 Schematic diagram of the turbulent flow generation component based on the bionic microchannel liquid cooling heat dissipation structure; Figure 7 is Figure 1 Schematic diagram of the gradient heat sink composite layer based on the bionic microchannel liquid cooling heat dissipation structure; Figure 8 is Figure 1 Schematic diagram of the gradient heat sink composite layer based on the bionic microchannel liquid cooling heat dissipation structure; Figure 9 is Figure 1 Schematic diagram of the swirl inlet based on the bionic microchannel liquid cooling heat dissipation structure; Figure 10 is Figure 1 Schematic diagram of the anti-vortex outlet based on the bionic microchannel liquid cooling heat dissipation structure; Figure 11 Schematic flow chart of the method for preparing the bionic microchannel liquid cooling heat dissipation structure of the present invention.

[0022] Explanation of reference numerals: Liquid cooling plate main body 1, fractal bionic microchannel 11, main channel 111, branch channel 112, hydrophobic area 113, hydrophilic area 114, optical fiber temperature sensor 12, turbulent flow generation component 2, triangular prism 21, hemispherical pit 22, gradient heat sink composite layer 3, copper composite matrix 31, micro-nano structure 32, thick copper base layer 33, transition layer 34, diamond layer 35, swirl inlet 4, spiral guide vane 41, anti-vortex outlet 5, gradually expanding anti-vortex chamber 51, staggered baffle 52. Detailed implementation manners

[0023] For the convenience of understanding the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0024] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs. The terms used in the description of the present invention herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention.

[0026] As Figures 1 to 11 shown, in one embodiment of the present invention, a bionic microchannel liquid cooling structure is involved, which includes a liquid cooling plate body 1, a turbulent flow generating component 2, and a gradient heat sink composite layer 3. A fractal bionic microchannel 11 is provided inside the liquid cooling plate body 1. The fractal bionic microchannel 11 includes a main channel 111 and at least four levels of branch channels 112. Among them, the last-level branch channels 112 are distributed in a logarithmic spiral. The turbulent flow generating component 2 is composed of an array of triangular prisms 21 and hemispherical pits 22 arranged in an interleaved manner. The inclination angle of the triangular prism 21 is 25° to 55°. The gradient heat sink composite layer 3 includes a copper composite matrix 31 containing diamond and a surface micro-nano structure 32. The surface micro-nano structure 32 is an array of conical nano-columns with a height of 20 to 50 μm. In terms of the fractal bionic microchannel 11 of the present invention, its unique design brings efficient coolant distribution. The setting of the main channel 111 and at least four levels of branch channels 112, especially the logarithmic spiral distribution of the last-level branch channels 112, greatly increases the flow uniformity and coverage of the coolant in the liquid cooling plate body 1. Compared with traditional channels, the fractal structure enables the coolant to reach each heat generation 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 between the coolant and the inner wall of the liquid cooling plate body, strengthening the convective heat transfer and further enhancing the heat dissipation performance. The turbulent flow generating component 2 is composed of an array of triangular prisms 21 and hemispherical pits 22 arranged in an interleaved manner, where the inclination angle of the triangular prism 21 is between 25° and 55°, which can effectively disrupt the flow state of the coolant and promote the formation of turbulent flow. The generation of turbulent flow breaks the limitation of the coolant boundary layer, enhances the mixing and heat exchange inside the coolant, significantly increases the convective heat transfer coefficient, and thus improves the heat dissipation effect. The specific structure and angle setting can ensure the stability of the coolant flow while promoting turbulent flow and avoid excessive pressure loss. The copper composite matrix 31 containing diamond in the gradient heat sink composite layer 3 itself has high thermal conductivity and can quickly transfer heat from the heat source. The micro-nano structure of the conical nano-column array with a surface height of 20 to 50 μm greatly increases the surface heat dissipation area. Through the synergistic effect of thermal radiation and convection at the micro-nano scale, the heat dissipation efficiency is further improved, enabling the entire liquid cooling structure to more efficiently meet the heat dissipation requirements of high-power heat generating devices.

[0027] The gradient heat sink composite layer 3 is covered on the fractal bionic microchannel 11 through a physical vapor deposition process. The gradient heat sink composite layer 3 is used to conduct the heat of the chip to the coolant. The turbulent flow generating component 2 forms an array of triangular prisms 21 and hemispherical pits 22 on the surface of the gradient heat sink composite layer 3 through a laser micro-texturing processing technique. In this embodiment, the gradient heat sink composite layer 3 is covered on the fractal bionic microchannel 11 through a physical vapor deposition process, greatly improving the heat conduction efficiency from the chip to the coolant. With its unique material properties and structure, the gradient heat sink composite layer 3 effectively reduces the thermal resistance, enabling heat to be quickly and evenly transferred from the chip to the coolant, avoiding local overheating of the chip, extending the service life of the chip, and ensuring its stable operation. The array of triangular prisms 21 and hemispherical pits 22 formed on the surface of the gradient heat sink composite layer 3 by the laser micro-texturing processing technique of the present invention, as the turbulent flow generating component 2, can effectively disrupt the flow state of the coolant and promote the formation of turbulent flow in the coolant. The generation of turbulent flow increases the contact area and disturbance degree between the coolant and the surface of the gradient heat sink composite layer 3, improves the convective heat transfer coefficient between the coolant and the heat sink composite layer, and further enhances the heat dissipation effect.

[0028] The hydraulic diameter of the microchannel is 0.5 - 1.2 mm, the aspect ratio > 50, and the heat dissipation power density ≥ 150 W / cm². In this embodiment, the combination of a smaller hydraulic diameter and a larger aspect ratio greatly increases the contact area between the coolant and the microchannel wall surface, strengthens the convective heat transfer process between the coolant and the heat dissipation structure, and makes the heat exchange more sufficient and efficient. The high heat dissipation power density indicates that this structure can quickly dissipate a large amount of heat per unit area, effectively cope with the high heat generated during the operation of high-power devices, and ensure the stable operation of the device in a suitable temperature environment. The bionic microchannel structure combined with the microchannel with specific parameters simulates the efficient substance transport system in the organism, optimizes the flow uniformity of the coolant, reduces the generation of local hot spots, and improves the overall heat dissipation performance.

[0029] In the above embodiment, the cooperative heat dissipation effect of the fractal microchannel and the turbulent flow component is tested The bifurcation angle of the branch channel 112 is 70° - 110°, and the cross-sectional area of adjacent hierarchical channels gradually decreases. In this embodiment, the angle range can effectively guide the flow direction and distribution of the coolant in the channel. When the coolant flows through the bifurcation, this angle enables the coolant to be more evenly distributed into each branch channel 112, avoiding the situation of excessive or too small local flow rate, thereby improving the uniformity of the overall heat dissipation efficiency. And the cross-sectional area of adjacent hierarchical channels gradually decreases. As the coolant flows in the channel, the gradually decreasing cross-sectional area can increase the flow rate of the coolant accordingly. The increase in flow rate helps to enhance the convective heat transfer coefficient between the coolant and the channel wall, and can transfer heat from the heat source to the coolant more efficiently.

[0030] The height of the triangular prism 21 is 1 / 4 to 1 / 2 of the height of the fractal bionic microchannel 11. The ratio of the adjacent prism spacing to the prism height is 1.2 to 2.0. The arrangement density of the hemispherical pits 22 array is 50 to 200 pits / cm². In this embodiment, the specific ratio of the height of the triangular prism 21 to the height of the fractal bionic microchannel 11, that is, the height of the triangular prism 21 is 1 / 4 to 1 / 2 of the height of the fractal bionic microchannel 11, is of great significance for optimizing the heat dissipation performance. This ratio can effectively guide the coolant to form a suitable flow state in the microchannel, enhancing the contact and heat transfer efficiency between the coolant and the channel wall. The ratio of the adjacent prism spacing to the prism height in the range of 1.2 to 2.0 can adjust the flow rate and flow direction of the coolant, promoting the uniform distribution of the coolant throughout the heat dissipation area and avoiding local overheating. The arrangement density of the hemispherical pits 22 array being 50 to 200 pits / cm² further increases the contact area between the coolant and the heat dissipation surface, strengthens the turbulence degree of the coolant, and effectively improves the heat dissipation coefficient of the heat dissipation structure.

[0031] The copper composite substrate 31 includes a copper base layer 33 with a thickness of 50 to 100 μm, a transition layer 34 with a thickness of 30 to 50 μm, and a diamond layer 35 with a thickness of 10 to 30 μm. The transition layer 34 is a copper-diamond gradient composite material. In this embodiment, the copper base layer with a thickness of 50 to 100 μm, relying on its good electrical conductivity and thermal conductivity, can efficiently collect and initially conduct heat, laying a solid heat dissipation foundation for the entire heat dissipation system. The 30 to 50 μm transition layer 34, as a copper-diamond gradient composite material, plays a key role in connection and optimization. It effectively alleviates the interfacial thermal resistance problem caused by the material property differences between the copper base layer and the diamond layer 35, making the heat transfer more smooth and efficient, and reducing the heat dissipation hindrance caused by the sudden change of thermal resistance. The 10 to 30 μm diamond layer 35, with its ultra-high thermal conductivity, can quickly dissipate heat, significantly improving the heat dissipation efficiency.

[0032] Refer to Figures 9 to 10As shown, it further includes a swirl inlet 4 and an anti-vortex outlet 5. The swirl inlet 4 is provided with spiral guide vanes 41, and the lift angle of the spiral guide vanes 41 is 15° - 30°. The anti-vortex outlet 5 is provided with a gradually expanding vortex elimination chamber 51 and staggered baffles 52. In this embodiment, the spiral guide vanes 41 provided at the swirl inlet 4 have a lift angle between 15° and 30°, which can make the coolant enter the system in a specific spiral manner. On the one hand, the spiral flow can enhance the contact and friction between the coolant and the microchannel wall surface, greatly improving the turbulence degree of the coolant, thereby increasing the convective heat transfer coefficient and significantly enhancing the heat dissipation effect. On the other hand, this orderly spiral flow helps to stabilize the flow pattern of the coolant, reducing flow dead zones and local overheating phenomena. The design of the gradually expanding vortex elimination chamber 51 and the staggered baffles 52 at the anti-vortex outlet 5 can effectively eliminate the vortices generated when the coolant flows out. The gradually expanding structure can reduce the fluid velocity, decrease the kinetic energy of the fluid, and inhibit the generation and development of vortices. The staggered baffles 52 further disrupt the shape of the vortices, causing the vortices to dissipate, ensuring the smooth outflow of the coolant, and avoiding problems such as pressure fluctuations and uneven flow rates caused by vortices.

[0033] The liquid cooling plate body 1 is provided with a plurality of fiber optic temperature sensors 12. The plurality of fiber optic temperature sensors 12 are arranged in an array on the liquid cooling plate body 1, and the distance between adjacent fiber optic temperature sensors 12 is 2 - 5 mm. In this embodiment, the temperature distribution on the surface of the liquid cooling plate body can be accurately sensed. Due to the small sensor spacing, temperature changes in a small area can be captured, providing detailed and comprehensive data support for monitoring the heat dissipation effect of the coolant in the bionic microchannel. It helps to promptly detect abnormal heat dissipation points. During the operation of the liquid cooling system, if the heat dissipation in a local area is poor and the temperature rises abnormally, the closely arranged sensors can quickly sense and feedback, so that technicians can promptly adjust the system parameters or troubleshoot faults. By obtaining a large amount of dense temperature data, the design of the bionic microchannel can be further optimized. Based on these temperature information, key parameters such as the structure of the microchannel and the flow rate of the coolant can be targeted for improvement.

[0034] In the above embodiment, performance verification of the gradient heat sink layer and the flow guiding structure The inner surface of the fractal bionic microchannel 11 is provided with a hydrophobic area 113 and a hydrophilic area 114, and the hydrophobic area 113 and the hydrophilic area 114 are alternately arranged, the contact angle of the hydrophobic area 113 is greater than 150°, the contact angle of the hydrophilic area 114 is less than 30°, and the alternating period is 3 to 8 mm. In this embodiment, the contact angle of the hydrophobic area 113 is greater than 150°, so that it exhibits extremely strong hydrophobicity, which can effectively prevent the liquid from adhering to and spreading in this area, prompting the liquid to quickly converge into droplets and form a form that is conducive to flow. The contact angle of the hydrophilic area 114 is less than 30°, showing good hydrophilicity and can quickly guide the liquid to flow in a directional manner. The alternating period is set at 3 to 8 mm. This reasonable range allows the liquid to maintain an appropriate flow rhythm in the microchannel, avoiding uneven liquid distribution due to a long period, and preventing flow disturbances caused by a short period. This alternating arrangement significantly optimizes the coolant flow within the microchannels, enhancing contact and heat exchange efficiency between the coolant and the microchannel walls. This in turn improves the heat dissipation performance of the entire liquid-cooled heat dissipation structure, ensuring efficient and stable system operation. This effectively reduces the high heat generated by the equipment during operation, ensuring continuous and stable operation at a suitable temperature, reducing performance degradation and component aging caused by overheating, and extending the equipment's service life.

[0035] The cross-section of the branch channel 112 is a gradient rectangle, with a width attenuation rate of 0.5~1.2% / mm along the flow direction and a depth increase rate of 0.3~0.8% / mm. In this embodiment, the width attenuation rate along the flow direction is controlled at 0.5~1.2% / mm, which can effectively regulate the flow rate and pressure distribution of the fluid in the channel. As the width decays, the fluid velocity will change accordingly, prompting the coolant to contact the channel wall more fully, enhancing the convection heat transfer coefficient, and improving the heat dissipation efficiency. The depth increase rate is 0.3~0.8% / mm, which increases the storage capacity of the coolant and extends the residence time of the coolant in the channel, which is conducive to absorbing more heat. This gradual design can also avoid local overheating, make the heat distribution more uniform, and effectively reduce thermal resistance.

[0036] The main body of the liquid cooling plate adopts a chromium-zirconium-copper alloy substrate, and its outer surface is treated with plasma nitriding with a thickness of 10 to 30 μm and a hardness of ≥800 HV. In this embodiment, the chromium-zirconium-copper alloy substrate has excellent thermal conductivity, laying a solid foundation for efficient heat dissipation, and can quickly transfer heat from the heat source to all parts of the liquid cooling plate body. The plasma nitriding layer with a thickness of 10 to 30 μm on the outer surface plays a key role. Its hardness of ≥800 HV greatly improves the wear resistance and corrosion resistance of the liquid cooling plate body, extends its service life, and reduces the risk of performance degradation due to wear or corrosion. This treatment enables the liquid cooling plate body to maintain a stable structure and performance even in complex and harsh working environments.

[0037] In the above embodiments, the chromium-zirconium-copper alloy matrix: Cu content ≥ 99.2 wt%, Cr 0.15 - 0.25 wt%, Zr 0.08 - 0.12 wt%; total impurity elements ≤ 0.05 wt% (including O ≤ 0.003 wt%, S ≤ 0.005 wt%).

[0038] The gradient composite of the transition layer: the volume fraction gradient of diamond: linearly increases from 0% in the copper base layer to 85% in the diamond layer; the D50 particle size of diamond grains: 5 μm at the bottom of the transition layer → 25 μm at the top (gradient change).

[0039] The plasma nitriding treatment layer: the nitrided layer contains ε-Fe3N phase (60 - 75%) + γ'-Fe4N phase (25 - 40%); the surface nitrogen concentration gradient: the surface layer ≥ 12 at% → the matrix interface ≤ 3 at%.

[0040] In the above embodiments, comparison of surface characteristics and material strengthening effects Refer to Figures 1 to 11As shown, a method for preparing a bionic microchannel liquid cooling heat dissipation structure, the method includes the following steps: Step S1, using selective laser melting to form the main body matrix of the liquid cooling plate, with a laser power of 200-400W, a scanning speed of 800-1200mm / s, a layer thickness of 20-50μm, and the surface roughness Ra of the formed fractal bionic microchannel 11 ≤ 3.2μm; Step S2, etching the turbulent flow generating component 2 on the inner wall of the fractal bionic microchannel 11 by micro-EDM, with a pulse width of 10-50μs, a current intensity of 3-8A, and a processing depth of 0.1-0.3mm; Step S3, using magnetron sputtering to deposit a gradient heat sink composite layer 3, first sputtering a 200-500nm titanium bonding layer, then depositing a 50μm copper layer, and finally depositing a diamond layer 35, with a sputtering power density of 8-12W / cm² and a substrate temperature of 400-600°C; Step S4, performing vacuum diffusion welding and encapsulation, with a welding pressure of 10-20MPa, maintaining the temperature at 750-800°C for 2-4h, and a vacuum degree ≤ 5×10⁻³Pa; Step S5, implementing micro-arc oxidation surface treatment, with the electrolyte containing 10-15g / L of sodium silicate, a voltage of 300-450V, and a treatment time of 10-30min, to generate a 20-50μm ceramic layer; Step S6, optimizing the flow channel parameters through particle image velocimetry technology, adjusting the spiral angle of the branch channel 112 to 20°-40°, so that the local Nusselt number Nu is increased by 15-25%. In this embodiment, in the process of forming the main body matrix of the liquid cooling plate by selective laser melting, parameters such as laser power, scanning speed, and layer thickness are precisely controlled to ensure that the surface roughness of the formed fractal bionic 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 turbulent flow generating component 2 by micro-EDM, under specific pulse width, current intensity, and processing depth, the fluid can form turbulent flow in the microchannel, greatly enhancing the heat transfer efficiency between the fluid and the microchannel wall surface and improving the heat dissipation performance. Magnetron sputtering deposits the gradient heat sink composite layer 3, and reasonable control of the sputtering power density and substrate temperature enables the titanium bonding layer, copper layer, and diamond layer 35 to be tightly combined and have excellent performance. The titanium bonding layer enhances the adhesion between the layers, the good thermal conductivity of the copper layer can quickly conduct heat, and the diamond layer 35 further improves the heat dissipation efficiency and wear resistance. Vacuum diffusion welding and encapsulation under appropriate pressure, temperature, and vacuum degree conditions ensure the sealing and overall strength of the liquid cooling structure, avoiding coolant leakage and structural 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 through particle image velocimetry technology and adjusting the spiral angle of the branch channel 112, the local Nusselt number is effectively increased, significantly enhancing the heat dissipation capacity of the liquid cooling heat dissipation structure and meeting the heat dissipation requirements of high-power devices.

[0041] In the above embodiments, in the step of magnetron sputtering deposition, the copper layer is doped with 0.5-1.2 wt% of nano-Al2O3 particles (particle size 50-80 nm) to improve the creep resistance.

[0042] In the step of vacuum diffusion welding, an Ag-Cu-Ti active filler metal (Ag72Cu26Ti2 wt%) is used, and the thickness of the solder joint is controlled to be 10-15 μm.

[0043] In the step of micro-arc oxidation treatment, nano-ZrO2 (2-5 g / L) is added to the electrolyte to generate a Zr-doped ceramic layer, which improves the thermal shock resistance.

[0044] The above embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A bionic microchannel liquid cooling heat dissipation structure, characterized in that: including a liquid-cooled plate body, wherein a fractal bionic microchannel is arranged inside the liquid-cooled plate body, the fractal bionic microchannel comprises a main channel and at least four levels of branch channels, and the last-level branch channels are distributed in a logarithmic spiral; a turbulent flow generating component, which is composed of an array of triangular prisms and hemispherical pits arranged in a staggered manner, and the inclination angle of the triangular prisms is 25°-55°; a gradient heat sink composite layer, which includes a copper composite matrix containing diamond and a surface micro-nano structure, and the surface micro-nano structure is an array of conical nano-columns with a height of 20-50 μm; the gradient heat sink composite layer is covered on the fractal bionic microchannel through a physical vapor deposition process, and the gradient heat sink composite layer is used to conduct the heat of the chip to the coolant; the turbulent flow generating component forms an array of triangular prisms and hemispherical pits on the surface of the gradient heat sink composite layer through a laser micro-texturing processing technology; the hydraulic diameter of the microchannel 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 microchannel liquid cooling heat dissipation structure according to claim 1, wherein: the bifurcation angle of the branch channels is 70°-110°, and the cross-sectional areas of adjacent hierarchical channels gradually decrease.

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

4. The bionic microchannel liquid cooling heat dissipation structure according to claim 1, wherein: the copper composite matrix includes 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-diamond gradient composite material.

5. The bionic microchannel liquid cooling heat dissipation structure according to claim 1, wherein: also includes a swirl inlet and an anti-vortex outlet, the swirl inlet is provided with a spiral guide vane, the lift angle of the spiral guide vane is 15°-30°, and the anti-vortex outlet is provided with a gradually expanding anti-vortex chamber and staggered baffles.

6. The bionic microchannel liquid cooling heat dissipation structure according to claim 1, characterized in that: the liquid-cooled plate body is provided with a plurality of fiber optic temperature sensors, and the plurality of fiber optic temperature sensors are arranged in an array on the liquid-cooled plate body, and the spacing between adjacent fiber optic temperature sensors is 2-5 mm.

7. The bionic microchannel liquid cooling heat dissipation structure according to claim 1, wherein: the inner surface of the fractal bionic microchannel is provided with a hydrophobic area and a hydrophilic area, the hydrophobic area and the hydrophilic area are arranged alternately, the contact angle of the hydrophobic area is >150°, the contact angle of the hydrophilic area is <30°, and the alternating period is 3-8 mm.

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

9. The bionic microchannel liquid cooling heat dissipation structure according to claim 1, characterized in that: the liquid-cooled plate body adopts a chromium-zirconium copper alloy matrix, the thickness of the plasma nitriding treatment layer on its outer surface is 10-30 μm, and the hardness is ≥800 HV.

10. A method for preparing the bionic microchannel liquid cooling heat dissipation structure according to any one of claims 1 to 9, characterized in that: The method includes the following steps: Step S1, using selective laser melting to form the liquid-cooled plate body matrix, the laser power is 200-400 W, the scanning speed is 800-1200 mm / s, the layer thickness is 20-50 μm, and the surface roughness Ra of the formed fractal bionic microchannel is ≤3.2 μm; Step S2, etching the turbulent flow generating component on the inner wall of the fractal bionic microchannel through micro-EDM, the pulse width is 10-50 μs, the current intensity is 3-8 A, and the processing depth is 0.1-0.3 mm; Step S3: Deposit a gradient heat sink composite layer by magnetron sputtering. First, sputter a 200 - 500 nm titanium bonding layer, then deposit a 50 μm copper layer, and finally deposit a diamond layer. The sputtering power density is 8 - 12 W / cm², and the substrate temperature is 400 - 600 °C; Step S4: Perform vacuum diffusion welding and encapsulation. The welding pressure is 10 - 20 MPa, keep the temperature at 750 - 800 °C for 2 - 4 h, and the vacuum degree is ≤ 5×10⁻³ Pa; Step S5: Implement micro - arc oxidation surface treatment. The electrolyte contains 10 - 15 g / L sodium silicate, the voltage is 300 - 450 V, the treatment time is 10 - 30 min, and a 20 - 50 μm ceramic layer is formed; Step S6: Optimize the flow channel parameters through particle image velocimetry technology. Adjust the spiral angle of the branch channel to 20° - 40°, so that the local Nusselt number Nu is increased by 15 - 25%.

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