Structural effect of internal composite wick on the anti-gravity heat transfer performance of a concentric annular high-temperature heat pipe

The present study proposes a composite wick with superposed screens in order to optimize the anti-gravity heat transfer performance of a 300 mm long concentric annular high temperature heat pipe (CAHTHP). An analysis of the best screen combination is presented based on a capillary limit model and visualization experiments of liquid anti-gravity transport in wicks. The structural effect of the composite wick on the anti-gravity heat transfer performance of CAHTHP was observed experimentally. The results were compared with those gravity worked CAHTHP. According to the results of the experiments, the dense pore-sparse pore-dense pore screen combination was capable of achieving stable anti-gravity operation under a heating power of 1.9 kW for the CAHTHP. Using the screen combination and a sodium filling rate of 15%, the anti-gravity-worked CAHTHP exhibited good performance during start-up and temperature uniformity at an average temperature of 700 degrees C. 320 s was the frozen start-up time, and 40.9 degrees C was the maximum temperature difference between the hot and cold ends of the CAHTHP. It had a thermal resistance of 0.021 degrees C/W and an effective thermal conductivity of 1303 W/m center dot K. Gravity-worked CAHTHP had an effective thermal conductivity of 1316 W/m center dot K, which demonstrated that the composite wick helped the CAHTHP had a similar capacity for heat transfer in the anti-gravity mode as in the gravity mode.

Automated summary

This study proposes a composite wick to optimize the anti-gravity heat transfer performance of a concentric annular high temperature heat pipe. The experimental results show that the dense pore-sparse pore-dense pore screen combination can achieve stable anti-gravity operation, and the composite wick has an impact on the anti-gravity heat transfer performance of the heat pipe.