Thermal performance of a medium temperature cesium heat pipe at different inclination angles

The cesium heat pipe has great potential in the medium temperature heat transfer fields for its large heat transfer capacity and high isothermality. To present the thermal performance of a cesium heat pipe, especially under different inclination angles, a cesium heat pipe is fabricated and tested in this work. As a result, the applicability of the theoretical calculation of the transition temperature to the cesium heat pipe is verified by the maximum temperature variation rate. Then, the frozen startup process with a sonic limit is described in detail which obeys the same rule as other alkali metal heat pipes. Furthermore, the effects of the heating powers (317.2 W similar to 1416.2 W) and the inclination angles (0 degrees, 30 degrees, 60 degrees, 68 degrees, and 80 degrees) on the thermal performance of the cesium heat pipe are experimentally analyzed. To precisely evaluate the temperature uniformity, the standard deviation of axial temperature in the condenser is calculated. The results indicate that the cesium heat pipe shows excellent temperature uniformity at 68 degrees. The end of the condenser presents a non-negligible temperature gradient at 80 degrees which can be reduced by adding a heat shield in the adiabatic section.

Automated summary

This study fabricates and tests a cesium heat pipe to present its thermal performance, verifies the applicability of theoretical calculation for transition temperature, describes the frozen startup process, and analyzes the effects of heating power and inclination angle on thermal performance. The results show excellent temperature uniformity of the cesium heat pipe at 68 degrees and suggest adding a heat shield to reduce temperature gradient at 80 degrees.