Experimental study on heat transfer characteristics of pulsating heat pipe under vibration environment

Abstract

Understanding the heat transfer characteristics of pulsating heat pipe (PHP) under vibration condition is important for the specific applications of PHP in moving vehicles, working machines or handheld equipment. In this paper, an experimental system for testing the thermal performance of PHP under different vibration conditions was built, the effects of vibration frequency and vibration amplitude on the temperature oscillation characteristics, overall heat transfer performance (thermal resistance and equivalent heat conductivity), start-up performance (start-up temperature and start-up time) of PHP have been analyzed. The results show that more obvious influences of vibration frequency and amplitude on the heat transfer performance of PHP can be observed under lower heat input condition. Increasing vibration frequency will reduce the overall thermal resistance, start-up time and start-up temperature, and increase equivalent heat conductivity. However, increasing vibration amplitude will enhance the overall thermal resistance and reduce the equivalent thermal conductivity, and increase both start-up time and start-up temperature. Therefore, better heat transfer performance of PHP can be obtained under high-frequency vibration environment or small amplitude vibration environment, as well as the start-up performance. It is acknowledged that compared with non-vibration condition, the heat transfer performance of PHP is limited under low vibration frequency (fv ≤ 25Hz) or large vibration amplitude (a ≥0.8 mm).