Direct fluid cooling inside the stator of a high-speed electric motor

Electric compressors are a key component in making the aviation industry more sustainable by enabling electric or hydrogen aircraft. At the heart of these compressors lies an electric motor, often capable of delivering high performance in a small form factor. As these electric motors have a high energy density, selecting a proper cooling method is in order to keep them at safe operating temperatures. Currently, cooling the stator of the electric motor from the outside is a popular method, as it is simple to implement. However, it is relatively ineffective compared to direct cooling methods, in which the windings in the stator are targeted directly. In this research, an investigation is performed on the applicability of a variety of direct cooling methods for electric motors specifically used in aircraft. A computationally efficient lumped-element model was developed in MATLAB Simscape for a quantitative comparison between these cooling strategies, after whi ch the most optimal method was found. A more elaborate conjugate heat transfer model in COMSOL Multiphysics was developed to perform various scenario studies with this new cooling strategy. The results show that both the temperatures and the volume of the electric motor could be significantly reduced using this new cooling method.