Study On Heat Transfer Enhancement Of Directionally Solidified Lotus-type Porous Copper Microchannel Heat Sink

The performance,reliability and service life of micro-electronic chip are affected by the operating temperature and its uniformity.With the increasing of electronic device integration,the power of electronic device increases,while the space for cooling is decreased.In order to meet the growing demand of electronic device heat dissipation,research on heat dissipation methods of high efficiency has become an important subject.The porous copper micro-channel heat sink has a low fabrication cost,the flow resistance is greatly reduced due to the multi-layered cylindrical hole with a smooth inner wall.Therefore,the porous copper micro-channel heat sink gradually becomes a heat material for heat dissipation of electronic devices.There have been many studies on the heat transfer coefficient of the porous copper,but the research on improving the surface temperature uniformity is few reported.Based on the porous copper fabricated by unidirectional solidification,this paper developed a new CPU cooling technology based on the porous copper prepared in the laboratory.Through experiment and simulation,with water and GaInSn liquid metal as coolant,this paper tests the influencing factors on the heat dissipation performance of porous copper micro-channel heat sink,especially the improvement of temperature uniformity.This paper uses Solidworks to model the porous copper microchannel heat sink by 1:1,and then selects the Flow Simulation module for thermal simulation.,analyzed the influence of gradient arrangement parameters on the heat transfer coefficient and temperature uniformity.In order to reduce the temperature difference and pressure drop of heat sink,porous copper is divided into several pore gradient array sections aligned in the direction of pore axis.Heat transfer performance of heat sink continuously improved with decreasing of the width of sections.There exists an optimal number of sections leading to the best heat transfer performance of lotus-type porous copper heat sink.Lotus-type porous copper heat sink achieved best heat transfer performance with 100 pore gradient array sections aligned in the direction of pore axis at a certain width and number of sections.This paper systematically tests the heat dissipation performance of the porous copper micro-channel heat sink under different pore gradient array parameters.The experimental results are basically consistent with numerical simulation results.When the porous copper with 100 pore gradient array is divided into 4 sections,the heat dissipation performance is significantly improved with water as its coolant in the flow of 100mL/s,which temperature difference reduced by 51% and import and export pressure drop of heat sink reduced by 48% compared to lotus-type porous copper heat sink without pore gradient array.In this paper,based on the study of the heat dissipation performance of the porous micro-channel heat sink,an engineering prototype for the CPU cooling was developed.Through installation and testing on the server host,it was found that the heat-dissipating capacity of the device can meet the heat-dissipation requirements either using water or liquid GaInSn metal.The porous copper heat sink has certain application value in the field of CPU heat dissipation.