Simulation of cooling oil flow in electrical machines using a 3D CFD/CHT

Authors

L. Sharifian, J. de Smet, N. Shahangian - Toyota Motor Europe, R. Beykrich, A. Jeckel, S. Klier, L. Grupe - FEV

Summary

To exploit the full potential of an electric machine in a vehicle powertrain in terms of power output and efficiency, optimum cooling control of the machine must be ensured. In this context, the objective of this study was the development of a CFD methodology using multiphase approach (oil & air) to accurately simulate the oil flow behavior with a focus on the airgap of an electrical machine with oil spray cooling. Conjugate heat transfer simulation was used for simulation focusing on the winding heads.

The complex flow physics, which strongly influences the overall machine performance, is extremely difficult to investigate with pure measurement techniques. Therefore, 3D CFD was used here for clarification of the flow physics. For validation of the simulations, 2 main measurement techniques (drag torque and optical visualization) were used at speeds between 100 to 3000 rpm. In addition, local thermocouples were applied to evaluate the thermal behavior.
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