EXPERIMENTAL STUDY ON HEAT TRANSFER PERFORMANCE OF MICROSTRUCTURAL SURFACE SPRAY COOLING IN IGBT MODULES

Spray cooling can fulfill the cooling requirements of electronic devices, such as insulated gate biopolar transistor (IGBT) modules and power batteries. However, the effects of microstructure feature height and spray parameters on their heat transfer performance are not well understood. Therefore, a closed spray cooling test system was set up with 50:50 glycol aqueous solution as the cooling medium, and the effects of spray flow rate, medium temperature, and nozzle height on the heat transfer performance of spray cooling were investigated for various microstructure feature heights. It was found that the heat transfer coefficient was maximum when the nozzle height reached the tangency between the spray surface and the heat transfer surface, and the heat transfer effect was best when the microstructure height was 0.5 mm. The heat transfer coefficients at various flow rates increased with the increase in flow rate, and the maximum surface heat transfer coefficient of 1.76 W/(cm²·K) was obtained at a flow rate of 240 mL/min and a microstructure height of 0.5 mm. The heat transfer coefficient increased with the increase in temperature at various work temperatures and leveled off after 30°C. Similarly, the surface heat transfer coefficient reaches 1.79 W/(cm²·K) when the spray height is 17.3 mm and the height of the microstructure is 0.5 mm, indicating that the surface has the optimal heat transfer capacity. This study provides a theoretical foundation for the application of spray cooling in high-efficiency cooling of IGBT modules in new energy vehicles.