Study On The Performance Of Ionic Wind Cooling System For LED Of High Heat Flux

Associated technologies continue to be miniaturized in parallel with enhancements in their performance.Enhancement in performance is parallel with a substantial increase in power density.Heat dissipation and temperature uniformity problems have been a bottleneck for LED development.Therefore,LED is in need of an innovative and advanced cooling technology with the following attributes: high efficiency;low weight,volume and cost;low noise generator;low power consumption;flexible form factor;no moving parts.Ionic wind cooling technology has all the attributes mentioned above,which makes it probably become the next generation solution for LED thermal management.An ionic wind generator consisting of a emitting tip and a collecting electrode is designed based on corona discharge theory.An experimental system is built to test key factors having influence on its performance.Three factors are studied,including the shape of emitting electrode;the shape of collecting electrode and the gap between the electrodes.Moreover,an ionic wind cooling system for LED of high heat flux is developed,which is capable of a cooling area of 40mm×40mm.Finally,comparison test is designed for analysis of the ionic wind cooling system and the traditional forced convection cooling system.Specific contents are as follows:1.Microfabricated emitting electrode and collecting electrode are made of 1mm thick copper plate by laser processing equipment.The emitting electrode and the collecting electrode are then assembled to be a single ionic wind generator.Through experimental study,three factors are studied,including the grid hole area of collecting electrode,the emitter curvature radius and the gap between the two electrodes.The results are as follows: when the grid hole area is 1.0mm×1.0mm;the emitter curvature radius is 0.122mm;and the gap between the two electrodes is 5mm,the highest velocity of 2.45m/s is achieved.2.An experimental system is built to study the performance of ionic wind generator array.Three factors such as the longitudinal spacing of array,the transverse spacing of array and the angle between the collecting electrode and the radiating surface are studied one by one.The results are as follow: when the longitudinal spacing of array is 6mm;the transverse spacing of array is 2.64mm;the angle between the collecting electrode and the radiating surface is 30 degrees,the lowest temperature of 50.59 degrees Celsius is achieved.3.Study on the effect of heat flux and applied voltage on the ionic wind cooling system for LED is operated.A comparison test is designed to analyze the heat transfer performance of the ionic wind cooling system and the traditional forced convection cooling system.The results are as follow: with the heat flux of 0.3752 cm W,the heat performance is quite good,and the highest heat transfer coefficient of 75.56W/(?·K) is achieved;with the applied voltage of 4.2k V,the heat transfer coefficient of 66.71W/(?·K) is achieved;when the power consumption is less than 0.026 W,the ionic wind cooling system has absolute advantages with a heat transfer coefficient of 51.30W/(?·K).Study on the ionic wind cooling system have provided new ideas for the design and structural optimization of the ionic wind generator,and the study on heat transfer characteristics and cooling performances of the ionic wind cooling system have enriched the thermal management for the chip of high heat flux such as LED.