Fluid Flow and Thermal Analysis of an Axial Flux Permanent Magnet Eddy Current Brake

With the increasing requirements for miniaturization and high braking torque, it is now necessary to analyze the thermal characteristics to the same extent as the electromagnetic design for eddy current brakes. However, due to the lack of suitable convection heat transfer correlations for axial flux eddy current brakes, it brings difficulties to designers. To solve this problem, the correlations for an axial flux permanent magnet (PM) eddy current brake are derived using the computational fluid dynamics (CFD) and the least square method. The proposed correlations considered the changes in design parameters and temperatures of the eddy current brake, and the accuracy is verified by the CFD. Subsequently, convective heat transfer coefficients calculated through the correlations are assigned to a thermal network model of the eddy current brake, and the thermal network model is verified by experimental tests. The results show that the thermal network model can accurately predict temperatures of the eddy current brake. Since the time required to calculate convective heat transfer coefficients through the correlations is significantly less than that required through CFD, and the variation of the geometrical parameters and temperatures can be considered, these correlations are very suitable for use in the optimization process.