Experimental investigations on start-up and thermal performance of sodium heat pipe under swing conditions

High-temperature heat pipes (HTHPs) have a potential of being used for passive heat dissipation of marine nuclear reactors in emergency. In order to understand the influence of wave action on the performance of HTHPs, a sodium heat pipe is fabricated and experimentally tested in this work. The effects of low-frequency swing on start-up and thermal performance of this heat pipe are examined and compared with the static state tests. The results show that swinging motion has a negligible influence on the whole start-up performance of the heat pipe, however, it would lead to the small-amplitude periodic temperature fluctuations especially at the evaporator. Temperature fluctuation frequency is nearly corresponding to the swing, and the temperature fluctuation amplitude is increased with the swing amplitude. The steady-state thermal performance is slightly decreased with increasing swing speed and decreasing swing amplitude in terms of thermal resistance under test conditions, but the influence seems negligible as well. (C) 2020 Elsevier Ltd. All rights reserved.