Parameter sensitivity study on startup characteristics of high temperature potassium heat pipe

Due to high power density, compact structure and easy modular assembly, heat pipe cooled reactor (HPR) is considered as an excellent candidate for removable power supply system. The heat transfer characteristic of liquid metal heat pipe, which is the only device to conduct the heat from reactor core, is extremely important for the safe operation of HPR. In this paper, the heat transfer performances of high temperature potassium heat pipes (Φ28 × 800 mm) are tested under different heating power (300–1000 W), wick mesh (600 and 800), filling charge amount (20 g and 50 g) and inclination angle (0°, 45°, 90°). The results show there is a temperature difference of 170 °C in condensation section at heating power of 336 W. With the increase of heating power, the melting and propagation speed of the working fluid in container increases, and the heat pipe performance is improved. Both wick mesh and filling charge amount increasing can promote the heat transfer performance of heat pipes, the filling charge amount is the main influencing factor to prevent from overheating at evaporation section. However, the heat pipes, having 50 g potassium, have a great geyser boiling phenomenon at 45°and 90° which could threaten the safe operation of HPR. This study provides experimental data support and theoretical basis for design and optimization of liquid metal heat pipes.