Evaluation of Convection Heat Transfer Coefficients in Totally Enclosed PMSMs

This paper evaluates the convection heat transfer coefficients (CHTCs) of a totally enclosed permanent magnet synchronous machines (PMSMs). A generalized computational fluid dynamics (CFD) model is established to investigate the convection heat transfer phenomena inside the machine's cavity and determine the corresponding CHTCs without influence of axial through flow or internal cooling. The CHTCs calculated by CFD are then compared with the widely used empirical rules considering the impact of rotor speed. Subsequently, general convection correlations are suggested for various investigated regions.