Radial and Axial Inlet and Outlet Design for End Winding Cooling of High-Speed Integrated Flux-Switching Motor-Compressor

In this paper, radial and axial housing inlet and outlet designs are proposed to cool a novel high-speed integrated flux-switching motor-compressor. With special arrangements of inlets and outlets in the housing, thermal analysis shows that the end windings can be effectively cooled. The rotor poles of the proposed machine are designed in the shape of airfoils so that they function as the rotor of an axial-flow fan. As the machine rotates at high speed, air is drawn into the machine and accelerated in the rotor. In this process, the airflow also cools the machine through forced convection; as a result, the machine achieves self-cooling. In order to use this capability most effectively, it is necessary to optimize the air flow path within the machine in order to direct air to critical surfaces that must be cooled and also remain at a favorable point on the fan curve. This paper explores different housing inlet and outlet designs and their influence on the pressure drop and surface heat transfer coefficients. The electromagnetic performance is evaluated by 3-D finite element analysis (FEA), and 3-D computational fluid dynamics (CFD) simulations are used to evaluate the thermal-fluid performance including the convective heat transfer coefficient at different surfaces.