Flow and Heat Transfer Investigation of Liquid Heat Sink for an IGBT Module

This chapter deals with comparison of heat transfer performance of rectangular and circular mini channels liquid heat sink for cooling of real Insulated Gate Bipolar Transistor (IGBT) module. A three-dimensional steady-state simulation using Ansys Icepak is implemented for this investigation. In this chapter, IGBT module- SKM75GB12T4 made by SEMIKRON is used. The IGBT module is made of multilayers, in which a power of 200 W is dissipated on the silicon diode chip. Water as a coolant is passed through the mini channel at an inlet temperature of 305 K for different values of Reynolds numbers (396 to 989). It is observed that the heat transfer performance of rectangular channels is always better than that of circular channels both in terms of baseplate and junction temperature because the surface area to cross-sectional area ratio is higher in case of rectangular channels. Further, the aspect ratio of rectangular channel is varied in a range of 0.8–1.6 at different Reynolds numbers (396–989). A higher aspect ratio confirms better heat dissipation, although at higher Reynolds number (Re > 700) baseplate temperature is insensitive to the aspect ratio of the mini channel. Thermal resistance for rectangular and circular mini channel is obtained and its variation with channel height is also analysed. It is found to have lower thermal resistance in rectangular channel than circular. Results have shown lower thermal resistance with higher mini channel height. As per the requirements of junction to case thermal resistance value of 0.38 K/W provided by the manufacturer for safe operation of the IGBT, a rectangular mini channel with aspect ratio of 1.5 at Reynolds number of 989 gave the thermal resistance value of 0.39 K/W.