Study For Natural Convection Of The LED Street Lamp's Heat Sink

At present, the environmental and development issues become the core of the contemporary world issues. In the context of energy-saving emission reduction, green economy has become a more sustainable new industry. LED light source as a revolutionary new energy-saving environmental protection is the concern of the countries and regions of the world's strategic industries. If the heat sink of high power LED Street lamp is not good, will cause the LED luminous efficiency low, life expectancy shortened, LED chips, phosphor, package have serious changes the optical properties of materials, thermal is one of the promoting LED lighting key technologies need to be addressed.This article experimentally analyzed the natural convection cooling performance on the current mainstream of high power LED Street lamp-aluminum radiator. And established a three-dimensional physical modeling using CFD software, using whole discrete, the whole solution in radiator in space by natural convective heat transfer process are coupled numerical calculation, received the radiator heat balance around the stable temperature and cooling air flow of vector field. Numerical results and experimental results within 2% error, it ensures the reliability of the numerical calculation.Research found that the radiator in the large space in natural convection, the cold air around the radiator heated and moved up by the action of the buoyancy, the supplementary cold air came in, constantly cycle to heat away in the process, above the radiator forms a barrier area, hinder has around air entered radiator rib tablets middle of slot road, making rib tablets can not be full of natural convection. This paper focuses on the heat sink temperature and radiator cooling air flow characteristics around, have proposed a design of permeable structures in the middle and the bottom surface of substrate at both ends of the radiator slot. Change the air flow direction of disturbed flow cooling radiator, you can make the vertical flow of air in the middle of radiator, not only can damage the barrier region above the radiator, also increase the speed of air flow around the radiator, increasing the amount of cooling air circulation. In the same 50W power, the bottom surface of substrate of the LED lights through the open-type than the original model of the maximum temperature of 5 degrees lower, the average heat transfer coefficient of fin from 7.2W/(m~2·K) increased to 8.5 W/(m~2·K), significantly increased the high-power LED street lamp radiator cooling capacity.