In situ two-phase flow in pulsating heat pipe

The importance of cooling devices for solving the heat generation problems of electronic devices is increasing, and a heat pipe can provide the highest thermal performance. PHPs using water are commonly made of copper and silicon; however, aluminum is more sustainable than copper, and more economical than silicon (in addition to weight and durability advantages). However, aluminum has not been employed as a material for PHPs with water as the working fluid. This is because non-condensable hydrogen gas is generated from the reaction of aluminum and water at high temperature, leading to the stoppage of flows inside the PHPs and resulting in the worst thermal performance. In this study, a micro-nano surface treatment was applied to the surface of the aluminum. This prevented hydrogen gas formation by forming aluminum hydroxide, thereby removing possible reaction sites on the surface. The proposed method improved both the performance and durability of water-aluminum PHPs.