Cutting Copper Fiber Oriented Sintering Heat Sinks For Water Cooling Of LED And Their Performance Study

LED light sources are gradually applied to plant factories,but the problem of the heat dissipation causes the disadvantage of high energy consumption.Considering the water irrigation system of plant factorys,it is a reasonable way to design a water-cooled heat sink with high specific surface area and high porosity for solving the problem.Therefore,cutting copper fiber oriented sintering heat sinks for water cooling of LED were proposed in this work.The heat transfer performance and flow characteristics of the heat sinks were investigated by experiments and simulations.This paper mainly includes the following aspects:(1)The cutting copper fiber oriented sintering heat sink for water cooling of LED was designed and prepared.The heat transfer process in the heat sink and the thermal resistances of the corresponding process were analyzed.The evaluation index of heat transfer performance and flow characteristics of the heat sink was determined.(2)A performance test platform for the cutting copper fiber oriented sintering heat sink for water cooling of LED was set up.The heat transfer performance and flow characteristics of the heat sink were investigated by experiments.The results show that with the increase of the inlet flowrate,the heat transfer performance of cutting copper fiber oriented sintering heat sinks is enhanced,but the magnitude of enhancement decreases gradually.The pressure drop of the heat sinks increases with the increase of the inlet flowrate,and so does its increasing range.The temperature uniformity of the heat sinks increases with the increase of the inlet flowrate.Compared to cutting copper fiber random sintering heat sinks,the heat transfer performance of cutting copper fiber oriented sintering heat sinks is slightly worse,but their pressure drops are much lower and their comprehensive heat transfer performance is better.With the decrease of the porosity of sintered skeletons,the heat transfer performance of the heat sinks is enhanced slightly,but the pressure drop increases distinctly.The heat sinks with 80% porosity have better temperature uniformity.The equivalent diameter of cutting copper fibers has little impact on the heat transfer performance of the heat sinks.The smaller the equivalent diameter of fibers is,the greater the pressure drop is.When the equivalent diameter of fibers is 195.12μm,the heat sinks with 80% porosity have better temperature uniformity.(3)A numerical model of the cutting copper fiber oriented sintering heat sink for water cooling of LED was established.The heating power of LED,inertia loss coefficient and viscous resistance coefficient of cutting copper fiber oriented sintering skeletons were obtained by experiments.Fluent was used to simulate The flow and heat transfer of cooling water in the cutting copper fiber oriented sintering heat sink were simulated based on the commercial software FLUENT.The numerical results show good agreement with the experimental data,validating the accuracy of the numerical model.(4)The performances of the heat sinks under different structural parameters were predicted by numerical model.The numerical results show that at the same inlet flowrate,with the increase of the thickness of sintered skeletons,the pressure drop decreases,and the heat transfer performance of the heat sinks increases first and then weakens.When the thickness of sintered skeletons is 2mm,the heat sinks show the best heat transfer performance.At the same inlet flowrate,with the increase of the length of sintered skeletons,the pressure drop increases,and so does the heat transfer performance,but the increasing trend slows down gradually.