Analysis of Heat Transfer in the Air Gap of Electrical Machines Using Empirical Equations and Computational Fluid Dynamics

Abstract

This paper deals with the thermal analysis of the air gap using empirical equations and computational fluid dynamics (CFD). First, empirical equations are introduced to calculate the air gap heat transfer coefficients. The thermal air gap model is shown. Next, numerical modelling is discussed, namely the shear stress transport k-omega model. Afterwards, parametric air gap models are presented. The air gap heat transfer coefficients calculated from empirical equations are compared with the air gap heat transfer coefficients from CFD. Next, a comparison between the thermal resistances calculated using the empirical equations and between thermal resistances of CFD is shown. Finally, velocity air gap profiles with air gap temperature contours are presented.