Experimental and numerical study of stator end-winding cooling with impinging oil jet

As an efficient cooling technology, impinging jet was utilized to reduce end-winding temperature of electric machine stator in this study. Infrared imaging and numerical simulation technologies were applied to investigate heat dissipation efficiency of silicone oil jet on a real electric machine stator. Infrared camera is possible to measure end-winding temperature without influence on flow pattern and heat exchange. Numerical simulation results for end-winding temperature were validated by comparing to experimental results. Then heat transfer coefficient was calculated by inverse method, which is very difficult to be obtained by experimental method. The testing stator had three configurations, among which one was covered by aluminum foil at external surface and the other one had extra internal surface in order to lead oil flow to contact all the end-windings. Moreover, effect of dissipated heat quantity and oil flow rate were considered in present study. According to experimental and simulation results, the configuration with internal surface reveals best cooling performance by impinging oil jet. For this stator configuration, the minimum and the most cost-effective oil flow rates were found which will provide insight for impinging jet system.

Automated summary

In this study, impinging jet was used as an efficient cooling technology to reduce the end-winding temperature of an electric machine stator. Infrared imaging and numerical simulation were utilized to analyze the heat dissipation efficiency of silicone oil jet on a real stator. The results showed that the configuration with an internal surface exhibited the best cooling performance, and the minimum and most cost-effective oil flow rates were determined for this configuration.