Abstract
Toward the improvement of performance of the electric vehicle (EV), the design of the motor shape appropriate to heat removal is important. A typical EV motor is composed of the pair of coaxial cylinders with the fixed outer cylinder (i.e., stator) and rotating inner cylinder (i.e., rotor). The present study experimentally and numerically clarifies the influence of inner shape on thermo-fluid characteristics of the EV motor. The flow behavior in slits between the rotor and stator was measured via PIV. The heat transfer of the gap between the rotor and stator was obtained by the numerical calculation. Furthermore, thermal network was introduced in order to estimate thermo-fluid characteristics among every component of the EV motor. In flow visualization via PIV, vortex flow was observed in the slit on the stator wall. In the numerical calculation, the heat transfer rate of with slit case in the high rotational speed was increased compared with that of without slit case. Hence, it was implied that the heat flux was increased by the presence of vortex of the internal slits. In the temperature estimation, difference between thermal resistances without slit case and with slit case did not affect temperatures of each component.
