Experimental investigation on reactivation characteristics of liquid-metal heat pipes after hydrogen inactivation

The use of a hydrogen window provides an effective way for liquid-metal heat pipes (LMHPs) to prevent hydrogen inactivation when operated in a hydrogen-containing atmosphere. This work experimentally investigates the effects of various operational conditions on the reactivation characteristics of LMHPs after hydrogen inactivation. Theoretical analysis and sensitivity analysis are conducted to enhance our understanding and optimize reactivation operations. The results indicate that a slope-shaped distribution of hydrogen buffer enable faster reactivation compared to a near-column shape. A sweep-gas flow rate in 200 mL/min is preferred under test conditions, when both the reactivation time and the pure N2 consumption rate are considered. The working temperature significantly affects the reactivation time, as higher temperatures accelerate the NaH decomposition and increase the hydrogen permeability of hydrogen window. The varying of pressure and preheating temperature of sweep gas under test conditions just have little influence on the reactivation time. In practical conditions, vacuum operations are not recommended due to its extremely low hydrogen-removal rate.

Automated summary

This study experimentally investigates the reactivation characteristics of liquid-metal heat pipes (LMHPs) after hydrogen inactivation and optimizes the reactivation operations using theoretical and sensitivity analysis. The results demonstrate that a slope-shaped distribution of hydrogen buffer enables faster reactivation compared to a near-column shape. A sweep-gas flow rate of 200 mL/min is the preferred option under test conditions, considering both reactivation time and pure N2 consumption rate. The working temperature significantly affects the reactivation time, while pressure and preheating temperature of sweep gas have little influence.