Thermal Analysis of a Rotor Oil Jet Cooled Electric Motor with Hairpin Windings

This paper proposes a hybrid multiphase CFD modeling approach to analyze the heat transfer in a rotor oil jet cooled electric motor. The model incorporates a detailed and representative end-winding geometry of a state-of-the-art electric motor with hairpin windings. The end-winding oil flow distribution and convective heat transfer is studied. The resulting convective heat transfer coefficients are imported into a multi-sector lumped parameter model of the stator assembly. The model is used to evaluate the maximum continuous cooling performance of the cooling concept for two different speeds and flow rates.