Experimental Study of a High-Temperature Oscillating Heat Pipe Using Infrared Imaging

Abstract In this study, an apparatus is constructed to perform infrared (IR) visualization experiments on a high-temperature oscillating heat pipe (HTOHP). Experiments are carried out on an HTOHP with caesium as the working fluid at 7 heating powers and a cooling temperature of 180 °C. The HTOHP starts up at 200 W and reaches the heat transfer limit at 500W. As the heating power increases, the thermal performance of HTOHP gets better before the limit. The wall temperature field variations obtained by the IR camera show the apparent differences in temperature distribution between the two side pipes when the HTOHP is in the unidirectional flow state. The overall increase in the wall temperature field with increasing heating power reflects the increase in the amount of heat it transfers. When the limit is reached, the temperature of the condensation section of the HTOHP reduces to the molten salt cooling temperature. An analysis of the thermal performance of the HTOHP shows that as the heating power increases, the average thermal resistance decreases by 65 %, from 3.12 °C/W at 200 W to 1.09 °C/W at 450 W.