Heat Dissipation Theory Research Of High-power LED Based On Copper Mesh

High power LED is gradually replacing incandescent lamp and fluorescent lamp,becoming the fourth generation of green lighting source because of it has the advantages of energy saving,long life,environmental protection,safe low voltage,and can dimming randomly etc.But LED's electrical-optical conversion efficiency is still low at present,most of the input power is converted into heat,accumulates inside the LED chip,if the heat is not timely dissipated,it will seriously affect the light failure and service life of high power LED,so the study of heat dissipation of high power LED is necessary.This article aim at traditional radiator,such as aluminum fin,heat pipe,fan cooling having shortcomings of low efficiency,high weight,high cost and so on,concretely prove that the copper mesh radiator is better than traditional aluminum radiator on the thermal performance from theory and experiment angle.At the same time engage in deriving some coefficient model associated with copper mesh heat dissipation.According to this,finding that applying what copper mesh will lead to the best cooling effect,and verifying the correctness of theoretical derivation through interrelated experiment.On this basis,we designed a new type of high-power LED copper mesh light.In this paper,concrete work and achievements are as follows:1)Compared and analyzed the thermal resistance of the aluminum cooling mode and the copper mesh cooling mode,obtain that copper mesh radiator greatly reduce thermal resistance than aluminum radiator,make the life expectancy of LED increase from 50,000 to80,000 hours;Compared and calculated the convection coefficient of the plate,slice and single copper wire,reach the conclusion that the natural convection coefficient of copper wire is much larger than the plate and slice;Designed copper mesh and aluminum plate bull contrast experiment,verify that the copper mesh has better thermal performance compared to aluminum radiator.2)Established the unit geometry model of square mesh and diamond mesh.In order to calculate the length of unit copper wire more accurately,using the arc curved algorithm.Derived the theoretical heat transfer coefficient model of the copper mesh about effective heat dissipation surface area ?,porosity ?,in-plane effective thermal conductivity ke,perpendicular in-plane effective thermal conductivity k_e~*,friction factor f and convection coefficient haccording to the heat transfer theory.Among this,the derivation of thermal conductivity applied the conversion factor method,changed the circular cross section thermal resistance network into the rectangular cross section thermal resistance network.Draw the relationship graph between the various coefficients mathematical model and mesh number according to derivation of above,and get that which mesh copper use will result in the extreme value.3)Combined with the relationship graph of the heat flow ? at per unit length of copper mesh circle,the temperature increase ?t at unit area of copper when absorbed unit heat and mesh.Comprehensively analyze of the cooling model and get that it will have better cooling effect when use smaller mesh copper mesh.In order to verify the correctness of the theoretical derivation,conducted 20 mesh and 40 mesh copper mesh cooling comparison experiments,get the conclusion that the 20 mesh has the better cooling effect than 40 mesh.