Numerical Analysis And Experiment Study Of Porous Micro Heat Sink For High Power LED Array

LED(Light Emitting Diode) is a kind of electronic units that can make electrical energy converted into light. Due to its comparative advantages, LED is widely used in many occasions. However, 80%-90% of the electrical energy is converted into heat when working, which would cause lots of adverse effects on LED condition. Therefore, heat transfer is becoming one of the critical factors that restrict the application of LED.In this paper, firstly focused on the problem of heat transfer of LED, the recent research literature and the active cooling ways of LED are mainly analyzed. By comparing merit and fault of these ways, a novel porous micro heat sink water-cooled system is proposed for LED heat dissipation. The main contents of this study are as following:(1) By processing experimental investigation to examine the heat transfer performance of system, the porous micro heat sink for high power LED array use 5×5chip arrangement, and the porous core is made of copper wire. It is found that the temperature of T3 of the input power of 45 W and 75 W is 38.3? and 45.4?, respectively.(2) Modeling and simulating the experimental system, the numerical modeling results are compared with the experimental ones. It is showed that the temperature difference between simulation and experiment are less than 1 ?, which can provide reliable simulation method for subsequent study analysis tool.(3) The model is used to research the impact of the number of import and export, flow velocity, porosity on the thermal effect of system, and find part of the law to improve the cooling performance. With the same flow rate, two imports and exports can improve the thermal performance of system. Then, the velocity increased from 0.25m/s to 0.5m/s, i the system heat transfer effect is improved obviously. Porosity is smaller cooling effect is better, but also the flow resistance is increased. And even in the case of ambient temperatures up to 36 ?, the maximum temperature of the system chip has only 45.8?.(4)In order to improving the heat transfer effect of system, according to the above experiment and simulation work and using the verified simulation model, the down-empty structure is found. From the points of the chip substrate temperature uniformity, installation convenience and economy, the down-empty structure would be the best option.The purpose of this research is to offer a reference theory and design basis for solving the problem of high power LED array, which could improve the sustainable development and application of LED.