Spray cooling of power electronics using high temperature coolant and enhanced surface

Abstract

A spray cooling system was developed and tested for thermal management of power inverter modules utilized in automotive applications. System featured an array of 1 times 2 pressure atomized nozzles that used 90degC antifreeze coolant with 0.15 L/min-cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> liquid flow rate and 145 kPa pressure drop. Two cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> simulated device, having an enhanced spray surface with micro scale structures, reached up to 400 W/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> heat flux with only 14degC surface superheat. These experimental results demonstrated the capability of greatly reducing the overall thermal resistance of the inverter modules that are commonly cooled with single phase convective systems. Performance of the presented system proved the spray cooling of power electronics as an attractive option that enables high power densities while maintaining satisfactory and uniform device temperatures. In addition, due to the use of high temperature coolant at low flow rates, spray cooling offers compact and efficient system design.