A comprehensive review and experimental investigation on heat pipes application in electrical machines

The rapid development of transportation electrification brings unprecedented opportunities and challenges as well to the technological improvement of high power density motors. As the major restriction of the motor performance, thermal issues attract more attentions recently and heat pipe (HP), due to its ultra-high thermal conductivity and lightweight characteristics, is identified as a promising solution. Though HPs are attempted in cooling systems of electrical machines, it still needs to fully understand their thermal benefits. This
article provides a comprehensive review and performs a series of experimental investigations to fill the technology gaps for the HPs applications in electrical machines. Firstly, the HP technology is briefly introduced, followed by a detailed review on its applications in different locations of electrical machines with corresponding thermal improvements reported. Then, experimental tests are conducted to investigate the correlation between the HPs parameters and cooling effectiveness, including cross-sectional shape, bending angle, fins arrangement
and inclination angle. The obtained results and conclusions could provide a guideline for the promotion of HPs in future electrical machines for transportation.