Numerical Simulation Of Heat Transfer Mechanism Of Microchannel Heat Sink Based On LB Method

With the rapid improvement of the performance of electronic devices,the thermal load of the cooling system is greatly increased,and the heat exchange space tends to be miniaturized.The conventional gas-cooling and liquid-cooling technologies are difficult to meet the thermal management requirements of high-performance electronic devices.The microchannel heat sink has the outstanding advantages of compact structure and high heat exchange per unit volume,and has become an important technology for cooling large-scale integrated circuits and microelectronic devices.In present,the research on microchannel heat sink is mainly based on experimental research,which can only capture the change of the overall performance of the microchannel heat sink,and it is difficult to reveal the microscopic mechanism of internal flow and heat transfer.However,simulation studies often neglect the effect of thermophysical parameters for conjugate heat transfer between solid and liquid,and less consider the combined some effects of microscale effects on the microchannel heat sink,and rarely extend the mechanism research to the three-dimensional microchannel heat sink.The lack of these studies limits the understanding of the heat transfer mechanism of microchannel heat sinks,and also becomes the bottleneck for optimizing the heat transfer performance of microchannel heat sinks.Firstly,we have revealed the nature of the conjugate heat transfer problem by theoretical analysis.As the LB method has the advantages of easily dealing with complex boundaries and simple programming.We have fully considered the conjugate heat transfer between solid and fluid,and established the LB model describing the internal flow and energy transfer of the microchannel heat sink.Based on this model,the numerical effects of different structured surfaces,wall thickness,thermophysical parameters of solid and liquid,and Reynolds number on the flow and heat transfer of the microchannel heat sink are numerically studied.The results show that the structure of the channel has a significant effect on fluid flow and heat transfer.Increasing Re number and solid-liquid thermal conductivity ratio and reducing solid-liquid heat capacity ratio can optimize the heat transfer performance of microchannel heat sink.In addition,we comprehensively discuss the viscous heat dissipation effect,the inlet effect and the power rate fluid.The results show increasing Br number and the power rate index will cause the heat transfer performance of the microchannel heat sink to deteriorate.Finally,the research on microchannel heat sink is extended to three dimensions,and the size optimization of sidewall and the influence of solid-liquid thermal conductivity ratio is analyzed.The results show that increasing the thickness of the sidewall surface can increase the local Nu number of the sidewall surface,but it also leads to an increase in the temperature of the entire heat exchange system.Increasing the solid-liquid thermal conductivity ratio in a certain range can reduce the wall temperature of the microchannel heat sink.The research in this paper clarifies the variation of heat transfer performance of microchannel heat sink under different structural parameters and thermal properties,and reveals the heat transfer mechanism inside the microchannel heat sink under the influence of viscous heat dissipation effect and power rate index.The research results can provide theoretical guidance and data support for the enhancement of microchannel heat sink heat transfer performance.