Heat transfer characteristics of a concentric annular high temperature heat pipe under anti-gravity conditions

Abstract

Many industrial applications call for high-temperature heat pipes working in anti-gravity modes. In past studies, heat pipes with concentric annular structures were developed with certain levels of anti-gravity working ability in low-temperature ranges. In this study, a concentric annular high-temperature heat pipe (CAHTHP) used for anti-gravity operation was designed and fabricated. Under the anti-gravity working condition, the effects of inclination angle on the CAHTHP frozen startup performance and temperature uniformity were experimentally studied and compared with gravity-operated experiments. The results show that the CAHTHP can achieve stable anti-gravity operation under high flux heating and natural convection cooling. The anti-gravity working condition and the working inclination angle have slight effects on the frozen startup rapidity and temperature uniformity of the CAHTHP. For different inclination angles, the CAHTHP startup times are all similar at approximately 450 s, and the thermal resistance values are all smaller than 0.05 °C/W. Moreover, the anti-gravity frozen startup process variation of the CAHTHP is in good agreement with that of the frozen startup two-region model.