Multiphase flow and thermal analysis of hollow-shaft cooling system for motors of Electric Drive Units (EDUs)
2022-01-0805
03/29/2022
- Content
- Typical motor designs are limited by the installation space and working environment. The electrical losses in the various components of the motor such as stator, rotor and coils can be quite significant and as a result, thermal issue is a bottle neck to improve power and torque density. In order to mitigate the thermal issue, an effective liquid cooling system must be employed that ensures sufficient heat dissipation from the motor and helps to reduce packaging size. Although both stator and rotor are cooled in a typical motor, this paper discusses a multiphase oil-air mixture analysis on a spinning hollow rotor and rotor shaft subjected to forced oil cooling. Three-dimensional computational fluid dynamics (CFD) conjugate heat transfer (CHT) simulations were carried out to investigate flow and heat transfer. The effect of centrifugal force, shaft RPM, density gradients and secondary flows were investigated. Initially the computational model was validated with bench test data in terms of pressure loss for a specific flowrate of oil at a given temperature. Later the model was simulated at various shaft RPM, oil flowrates and rotor heat loss maps. Overall, the centrifugal force as a result of spinning shaft was shown to influence heat transfer. However certain regions within the shaft due to relative distribution of oil-air mixture had minimal effect. The RPM of the shaft was found to have a significant effect on heat transfer whereas the secondary flow due to density gradients had minimal effect.
- Citation
- Yashwanth, B., Ronning, J., Kolesnikov, A., and Mehta, Y., "Multiphase flow and thermal analysis of hollow-shaft cooling system for motors of Electric Drive Units (EDUs)," SAE Technical Paper 2022-01-0805, 2022, .