Thermal analysis of the oil cooling motor according to the churning phenomenon

In this study, the flow field and temperature distribution in a 160-kW commercial electric vehicle motor ac-cording to the churning phenomenon were investigated to analyze the effect of the churning phenomenon on the cooling performance of motor. To this end, experimental and numerical analysis were conducted to analyze the relationship between flow field and cooling performance. First, this study analyzed the effect of oil temperature on the motor cooling performance, and the results revealed that the average temperature decreased by 48.9 degrees C with a decrease in the oil temperature from 100 to 50 degrees C, but the temperature variation is increased by 10.2 %. Second, this study analyzed the effect of oil flow rate on the motor cooling performance, and the results revealed that with an increase in the oil flow rate from 5 to 10 LPM, the average temperature decreased by 8.7 degrees C, and the temperature variation is increased by 3.6 %. Lastly, this study analyzed the effect of motor rotation speed on the motor cooling performance, and the results revealed that the average temperature increased by 8 degrees C with an increase in the motor rotation speed from 8,700 to 14,000 RPM, and the temperature variation is increased by 34.4 %. These results indicate that the churning phenomenon results in a non-uniform temperature distribution and decreased the cooling efficiency by disturbing oil flow from the cooling pipe.