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Ionic Wind Development in Corona Discharge for LED Cooling

The working temperature of an LED chip has a great influence on its photoelectric properties. It is urgently necessary to develop an adaptive cooling device for LEDs’ heat management. This paper proposes a “multi-needle-to-mesh” ionic wind generator for enhanced heat transfer in high-power LEDs (HPLED). Experiments were conducted to evaluate the cooling performance of HPLEDs under multiple working conditions. The electric field intensity (EFI) distribution, the charge density, and the dynamic pressure of ionic wind were measured. We also investigated the thermal resistance, the mean heat transfer coefficient, and the output luminous flux of HPLEDs. The results indicate that the EFI distribution is inhomogeneous and there was a reduction in EFI from the needle tip to the collecting electrode of up to 90%. Furthermore, the density of discharges was proportional to the overvoltage but inversely proportional to the square of the discharge gap. The ionic wind velocity was proportional to the overvoltage but inversely proportional to the discharge gap. An approximately 34% reduction of thermal resistance was observed as well. The final reducing rate of HPLED output luminous flux was 9.3%under the action of ionic wind.