Heat transfer coefficient for water cooled heat sink: application for standard power modules cooling at high temperature

This study presents an overview of water cooling methods used in the power electronic field. The first one uses the classical method with separated power module and cooling device. The second one deals with high reduction of conductive thermal resistance and could predominately be the final cooling solution in the near future. The last one, foreseen for future applications, consists in designing the power module and the cooling device in the silicon material, improving even more the overall thermal resistance. Each alternative may require a good knowledge of the thermal exchange laws in the heat exchanger. The Nusselt number, as a characteristic thermal parameter proposed in the literature, is not always realistic for all kinds of cooling devices. The work focuses on that correlated value determination taking into account the channel geometry, the fluid flow rate and its temperature. Then, the obtained value is used to make a real optimisation of the cooling device.