Thermal and Hydraulic Performance of Water/Glycol Mixture and the Application on Power electronics Cooling

Abstract

Numerical simulations were conducted to study thermal and hydraulic performance of liquid-cooled heat sink on power electronics cooling, in particular with water/glycol mixture. Considering non-uniform and discrete heat sources, geometry and number of cooling channels were analyzed. The results show that alternating rectangular channel has high thermal performance with a little penalty in hydraulic resistance. The number of cooling channels can be optimized to provide the best thermal performance, as 40 channels for the analyzed case. Performance difference resulting from working coolants was studied, with 100% de-ionized water, mixture of 50% ethylene glycol and 50% de-ionized water (EGW) by weight, and mixture of 60% propylene glycol and 40% de-ionized water (PGW) by weight. The variations of fluid physical properties with temperature were taken into account. It has been concluded that lower coolant temperature does not necessarily lead to better cooling capacity, i.e. a specific coolant has an optimum operation temperature to provide the maximum cooling performance.