Critical and optimal inclination angles of two-phase closed thermosyphon under different operating conditions

Two-phase closed thermosyphon (TPCT) is widely used and usually installed vertically, but the inclination angle has significant effects on TPCT performance. This work presents an experimental study of TPCT with water as working fluid. The critical and optimal inclination angles of TPCT under non-forced convection cooling conditions are investigated from three aspects of start-up, operating, and heat transfer characteristics at different operating temperatures. The results show that TPCT has the critical inclination angle and the optimal inclination angle. A critical inclination angle of 45 degrees is obtained under different operating conditions. The optimal inclination angle of TPCT is 60 degrees at the operating temperature of 80-150 degrees C, but it is 90 degrees (vertical) at 150-185 degrees C. Furthermore, the start-up and heat transfer performance of TPCT gradually improves with the augment of heating power. This study provides a reference for future research on heat pipe performance enhancement methods and related applications, and presents experimental basis for performance changes in TPCT applications when accidental dry burning occurs. (c) 2021 Published by Elsevier Ltd.

Automated summary

This study investigates the critical and optimal inclination angles of TPCT under different working conditions, as well as the improvement of TPCT performance with increasing heating power. The results provide references for enhancing heat pipe performance and related applications, and also offer experimental basis for performance changes in TPCT applications when accidental dry burning occurs.