Conjugate Heat Transfer CFD Analysis of an Oil Cooled Automotive Electrical Motor

This study brings to forefront the analysis capability of CFD for the oil-cooling of an Electric-Motor (E-Motor) powering an automobile. With the rapid increase in electrically powered vehicle, there is an increasing need in the CFD modeling community to perform virtual simulations of the E-Motors to determine the viability of the designs and their performance capabilities. The thermal predictions are extremely vital as they have tremendous impact on the design, spacing and sizes of these motors. In this paper, with the Simerics, Inc. software, Simerics-MP+®, a complete three dimensional CFD with conjugate heat transfer CHT model of an Electric Motor, including all the important parts like the windings, rotor and stator laminate, endrings etc. is created. The multiphase Volume of Fluid (VOF) approach is used to model the oil flow inside this motor. Two parts of the oil flow, rotor and stator flow, both are simulated, and the net effect of the oil cooling the different solid components is predicted. The study shows the mesh capturing of complicated, intricate paths with relative ease combined with the robust high fidelity interface capturing VOF scheme with rapid turnaround times makes it a very attractive tool for design studies. Thermal results obtained from simulations are compared to physical test data obtained from thermocouple measurements and very good agreement is found.