Research On Heat Dissipation Of High Power LED Chips Based On Micro Jet

For LED, its low luminous efficiency results from no effective heat dissipation. As a result, it is very urgent and necessary to solve its heat dissipation problem. Micro jet system adopts impinging jet which has a good heat transfer coefficient. In a word, micro jet system can be a potential solution to heat dissipation problem of LED with high power.In this article, micro jet device will be the main topic. With numerical simulation, a study will be done on the following aspects:the effect of chip heat density, the effect of inlet flow, the effect of micro jet class number, the effect of micro jet radius, the effect of upper-down body size on micro jet device, and the effect of inlet water temperature. If inlet flow speed is0.8m/s and chips class number is2×2, the effect of heat dissipation will be better with micro jet class number2×2comparing with other class numbers and when the radius of the nozzle is0.2mm, the effect of heat dissipation is the best. It is better if the height of upper and down body can be as small as possible. When the height of upper and down body gets smaller, the effect of heat dissipation can be better accordingly.To optimize the structure of the micro jet, a study will be done on the following aspects:the effect of inlet&outlet number, the effect of the shape of micro jet device, the effect of chipset number, as well as the comparison of the structure without micro jet. Compared to one inlet and one outlet, the effect of heat dissipation is better if there is one inlet but two outlets. Among the three arrangements, the effect is the best if two inlets are on a straight line and inlet is vertical to the outlet. When the shape of the nozzle is cone, the effect of heat dissipation will be worse if the proportion of upper&down radius increases. The smaller the proportion of upper&down radius is, the better it is. Surely, when micro jet is doing heat dissipation, it is very necessary to choose a suitable class number and radius of micro jet. Otherwise, the effect can be even worse than water cooling.In the above simulation, working medium is water. The article studys refrigerant as the working medium first time.According to the background and principle when choosing refrigerant, the following common six ones are the preliminary options. They are R22, R123, R134a, R290, R407C and R410A. Analysis the performance of every refrigerant, provide some reference for further study.