Thermal management of electric motor is a significant criterion concerning the performance of the motor since it relies on the working temperature. This paper presents an experimental investigation of a thermal management system with a design based on the passive action of closed-loop pulsating heat pipes (CLPHP). The evaporator is a curved copper section termed the cooling pad, which inculcates the pulsating fluid regime and directly contacts the motor surface. Four such sets of CLPHPs are mounted on a test bench to study the performance characteristics of the system. Water–acetone binary mixture is selected as the working fluid and is tested for optimum mixing ratio by varying the acetone concentration through 40%, 50% and 60%. Performance study is carried out under different current readings of 1 A, 2 A, and 3 A, resulting in respective heat loads of 27 W, 109 W, and 240 W until the steady-state temperature is achieved. Filling ratios (FR) are taken as 40%, 50% and 60% of the total volume. The results obtained show that a 50% filling ratio with a 50% mixing ratio (MR) gives the optimum working condition by which the cooling system can reduce the motor temperature by 33.3 °C with a 47% increase in overall heat transfer coefficient compared to the natural convection of motor surface.

电动机的热管理是关于电动机性能的重要标准，因为它依赖于工作温度。本文介绍了基于闭环脉动热管 (CLPHP) 被动作用设计的热管理系统的实验研究。蒸发器是一个弯曲的铜部分，称为冷却垫，它灌输脉动流体状态并直接接触电机表面。将四套这样的 CLPHP 安装在测试台上以研究系统的性能特征。选择水-丙酮二元混合物作为工作流体，并通过改变 40%、50% 和 60% 的丙酮浓度来测试最佳混合比。性能研究在 1 A、2 A 和 3 A 的不同电流读数下进行，导致各自的热负荷为 27 W、109 W 和 240 W，直到达到稳态温度。填充率 (FR) 取总体积的 40%、50% 和 60%。获得的结果表明，50% 的填充率和 50% 的混合比 (MR) 给出了最佳工作条件，在该条件下，冷却系统可以将电机温度降低 33.3 °C，同时整体传热系数增加 47%。电机表面的自然对流。