Thermal analysis and thermal management of high power density electric motors for aircraft electrification

The aircraft electrification is a vital solution for creating sustainable transportation infrastructure, and developing high power density motors is the key to this electrification. However, the increase of power density will inevitably lead to the increase of motor losses density, resulting in the increase of motor temperature, which will lead to demagnetization of permanent magnets, reduction of the life of insulation materials, reduction of motor operating efficiency and even motor burning. Therefore, effective thermal management is the key to improve the power density and safety of motor. In this paper, the thermal analysis and thermal management of aircraft motors are comprehensively and systematically reviewed. Firstly, the heat source and energy loss of the motor are briefly analyzed. The current mainstream thermal analysis methods and emerging technologies are emphatically introduced, including finite element method, computational fluid dynamics, lumped parameter method, combination method and digital twinning, and the key problems, advantages, and disadvantages associated with each method are analyzed. Then, a comprehensive review of recent research on motor thermal management strategies is presented according to different cooling locations (housing, stator, winding, rotor). and several emerging thermal management technologies, such as superconducting motor, evaporative cooling, phase change material cooling and nanofluid cooling, are also emphatically introduced. Finally, some suggestions on potential future research and development of motor thermal management are put forward. This paper aims to provide inspiration and reference for aircraft motor designers and researchers in the development of efficient thermal management systems.