Research On Air Cooled Porous Micro Heat Sink For Heat Dissipation Of High Power LED Array

High power LED(Light Emitting Diode)as a new generation of semiconductor Light source,which has the advantages of energy-saving,environmental protection and long life,is widely research and attention.However,due to the limitation of electro-optical efficiency of LED,over 80% of the electrical energy is converted into heat,if the heat can't be effectively dissipation in time,which will lead to the junction temperature increased,decrease using life and luminescence efficiency of the LED.So,for high-power LED device application promotion,the heat dissipation is an urgent problem to be solved.In view of the high power LED with high heat flux,the strict junction temperature control characteristic,this paper proposes a new type of air cooled porous micro heat sink cooling technology to meet heat dissipation requirement of the high power LED.Firstly,establish the mathematical model of porous micro heat sink and the model for simulation according to the structure of the porous micro heat sink.Next is thermal simulation of the air cooled porous micro heat sink of high power LED array by using fluid simulation software Fluent.And the result show that the LED chip of maximum temperature is 62? under the condition of environmental is 27?,power of the LED array is 125 W.Finally,the effect factors of porous micro heat sink flow and heat transfer are analyzed by using the method of simulation,and draw the following conclusions.Increase inlet air velocity can effectively decrease the temperature of the LED chip,but the drop trend of temperature is decreasing;Decrease the porosity can improve the heat dissipation effect of porous micro heat sink,but it will increase the pressure drop of porous micro heat sink;Reduce the thickness of the porous wick,LED chip temperature gradually decreased,and the downward trend gradually increase;The LED chip temperature has linear relationship with the environmental temperature;The LED chip temperature also has linear relationship with the input power of LED array.Through the research of this paper,it could prove that the air cooled micro porous micro heat sink cooling technology can meet the demand of the heat dissipation of high-power LED arrays,this cooling technology provides a new way to dissipation heat for the application of high power LED.The result of analysis the factors affect the heat transfer performance of porous micro heat sink provides a theoretical basis for structure optimization design of porous micro heat sink.