Design And Fabrication Of Metal Micro-channel Heat Sink Used For The Cooling Of T/R Module

Micro-channel heat sink has the advantages of compact structure,small size,large heat transfer area,and can realize efficient heat dissipation in small space.So it has a broad application prospect in the fields of aerospace,national defense military electronic communication and so on.In this paper,a metal Micro-channel heat sink is designed and fabricated for the heat dissipation problem of T/R(Transmitter and Receiver)module with high heat flux,then the temperature at the bottom of heat sink and the heat transfer coefficient of heat sink is measured by experiments.In this paper,the simulation model about convection heat transfer in Micro-channel heat sink is established.The influence of cross section size on the flow and heat transfer characteristics in rectangular Micro-channel is studied by simulation.The results show that decreasing the width of Micro-channel will improve the heat transfer coefficient of Micro-channel and increase the pressure drop of working medium,and increasing the aspect ratio of Micro-channel will improve the heat transfer coefficient of Micro-channel and reduce the pressure drop of working medium.The influence of interval structure on the flow and heat transfer characteristics in Micro-channel array is studied by simulation.The results show that boundary layer was destroyed after adding interval structure and the heat transfer coefficient of Micro-channel array is increased by 88.8%~171.34%.In addition,interval structure increases the local resistance in the process of working medium flow,and makes the pressure drop of working medium increased by 8.2%~22.9%.Based on the second law of thermodynamics,the entropy generation of the flow and heat transfer in Micro-channel is analyzed.The influence of the geometry of Micro-channel on entropy generation is studied.According to the principle of entropy generation minimization,the final structure is determined.The width of Micro-channel is 100?m,height is 500?m.The Micro-channel is separated into three sections by interval structure,the length of each section is 2.5mm,3mm and 2.5mm,the size of interval structure is 1mm,the length of Micro-channel is 10mm.Micro-channel is fabricated on copper substrate by UV-lithography of SU-8photoresist and micro electroforming technology,then the altitude compensation of electroforming layer is used to realize the high strength welding between Micro-channel and cover plate.Finally,a metal Micro-channel heat sink is obtained.In order to test the heat exchange performance of metal Micro-channel heat sink,a testing system for heat transfer performance was established,and experimental equipment is examined.By measuring the temperature distribution of the heating block,it is confirmed that the heat conduction inside the heating block follow the rule of one-dimensional heat conduction in the vertical direction,which ensures the controllability of the heat flux density on the heating surface.By examining the air tightness of Micro-channel heat sink and the connecting pipes,it is confirmed the high strength welding between Micro-channel and cover plate,which avoids the leakage of working medium during the experiment.It is measured the temperature at the bottom of heat sink and the heat transfer coefficient of heat sink during the experiment under different conditions.The results show that the upper limit of temperature at the bottom of heat sink is 38.5?and the average heat transfer coefficient of metal Micro-channel heat-sink reaches 67.0 kW/(m~2·K)when the flow of working medium is1~1.8L/min and the heat flux density on the heating surface is 10~80W/cm~2.