Numerical Simulation Study Of The Effect Of Fin Arrangement On The Heat Transfer Performance Of Micro-pin-fin Heat Sink

With the continuous development of chip and micro-electromechanical structure processing technology,the number of transistors per unit area of a semiconductor chip still maintains a rapid growth trend,and the accompanying increase in heat generation brings serious challenges to the temperature management of the chip.At present,the traditional air cooling technology has been unable to meet the current temperature management needs,and the single-phase liquid cooling technology and the two-phase boiling cooling technology are expected to become the next generation cooling radiator technology of electronic components in the future due to their high cooling and heat dissipation efficiency,large heat dissipation potential,and simple structure.The research on single-phase liquid cooling and two-phase boiling cooling heat dissipation equipment mainly focuses on micro heat sinks.With the gradual diversification of the application fields of micro heat sinks,the optimization of working fluid flow,heat transfer and thermalhydraulic comprehensive performance of micro heat sinks has become an inevitable trend.The shape,size,height and spacing of the micro-pin-fin will have a huge impact on the flow and heat transfer performance of the micro-pin-fin heat sink.The current research work mainly unifies the longitudinal and transverse fin spacing as a single variable.In order to clarify the influence of the fin spacing changes on the working fluid,heat transfer and thermal-hydraulic performance of the micro-pin-fin heat sink under different pin-fin arrangements.In this paper,on the basis of building a single-phase heat transfer model of a square micro-pin-fin heat sink,the numerical simulation of the single-phase heat transfer process of the micro-pin-fin heat sink under different flow and heat flux density conditions is carried out.The fin spacing qualitatively summarizes the influence law of the changes of longitudinal and transverse spacing on the parameters of working fluid flow,heat transfer and thermal-hydraulic comprehensive performance.In addition,by constructing a comprehensive evaluation system for the micro-pin-fin heat sink,and according to the comprehensive evaluation results,the corresponding fin spacing optimization suggestions are put forward for different pin-fin arrangements.The main research conclusions are as follows:1)The change of the longitudinal spacing is mainly by affecting the size of the wake vortex,which changes the velocity and direction distribution in the entire fluid domain,resulting in changes in the flow and heat transfer characteristics of the micro-pin-fin heat sink,while the change in the transverse spacing is mainly by affecting the velocity of the fluid in the transverse inter-fin space changes,but due to the different fluid flow trajectories in the linear and cross-arranged microneedle fin radiators,the same change in the fin spacing may cause changes in the opposite trend.2)No matter for the linear or cross-arranged micro-pin-fin radiator,under the same Reynolds number,the relationship between the parameters of the working fluid flow,heat transfer and comprehensive characteristics with the fin spacing will not change due to the change of heat flux density.3)The influence of the change of fin spacing on the flow,heat transfer and comprehensive characteristics of the linearly arranged micro-pin-fin heat sink（1）Under the same Reynolds number,when the transverse spacing is kept constant,the Fanning friction coefficient increases with the increase of the longitudinal spacing,but the relationship between the pressure drop △p and the longitudinal spacing will be reversed due to the decrease in the number of pin fins per unit length.When the longitudinal spacing remains constant,both △p and f will decrease with the increase of the transverse spacing.（2）Under the same Reynolds number,when the transverse spacing is kept constant,the heat transfer coefficients per unit area h_fin and Nu increase first and then decrease with the increase of the longitudinal spacing,and the point corresponding to the maximum value increases with the difference between Re and transverse spacing.When the longitudinal spacing is kept constant,both h_fin and Nu will decrease with the increase of the transverse spacing.（3）Under the same Reynolds number,when the transverse spacing remains constant,its T_buave,T_bumax and Rtot first decrease and then increase with the increase of the longitudinal spacing,and the maximum value corresponding to The point shrinks with the increase of Re and transverse spacing,and when the longitudinal spacing remains constant,its T_buave,T_bumax and Rtot all decrease with the increase of transverse spacing.4)The influence of the change of the fin spacing on the working fluid,heat transfer and comprehensive characteristics of the linearly arranged micro-pin-fin heat sink（1）Under the same Reynolds number,when the longitudinal spacing or transverse spacing remains constant,the pressure drop △p and the Fanning friction coefficient f both decrease with the increase of the other fin spacing.（2）Under the same Reynolds number,when the longitudinal or transverse spacing remains constant,the heat transfer coefficients per unit area h_fin and Nu will both decrease with the increase of the other fin spacing.（3）Under the same Reynolds number,when the longitudinal spacing or transverse spacing remains constant,its T_buave,T_bumax and Rtot will increase with the increase of another fin spacing.5)For the linearly arranged micro-pin-fin heat sink,its comprehensive performance increases with the decrease of the transverse spacing,and it shows a trend of first increasing and then decreasing with the increase of the longitudinal spacing,and the longitudinal spacing corresponding to the optimal point of comprehensive performance increases with Re increase or decrease in transverse spacing.For the cross-arranged micro-pin-fin heat sink,the variation trend of its heat transfer performance and comprehensive thermal hydraulic performance with the fin spacing is often not the same.