Thermal Analysis of an Oil Jet Cooled Electric Motor with Hairpin Windings

This paper proposes a multiphase CFD model to analyze the heat transfer in oil jet cooled electric motor hairpin end-windings. The model includes a detailed and representative end-winding geometry for both crown- and weld-side end-windings of a state-of-the-art electric motor hairpin winding. The convective heat transfer of the cooling method is studied, and a set of heat transfer coefficients is derived. These heat transfer coefficients are imported in a multi-sectorial lumped parameter model of the stator. Finally, the global heat transfer within the stator is evaluated for three different flowrates.