Hot Reservoir Variable Conductance Heat Pipe with Advanced Fluid Management

A hot reservoir variable conductance heat pipe (VCHP) can offer a significantly tighter passive thermal control than a regular VCHP with a cold-biased reservoir. This attribute makes the hot reservoir VCHP an ideal thermal management device for future planetary landers and rovers and especially for the moon where surviving of the lunar night is energetically challenging. Since the hot reservoir cannot be wicked, it becomes a challenge to properly manage the presence of working fluid within the reservoir. To ensure a long-duration operation of the hot reservoir VCHPs in reduced gravity and in microgravity, advanced fluid management strategies and features must to be developed. Advanced Cooling Technologies, Inc (ACT) in collaboration with Case Western Reserve University (CWRU) is developing a reliable VCHP configuration under the NASA STTR program. The novel VCHP consists of a loop with well-engineered tubing configuration, that would generate a momentum induced continuous flow within the device. This induced flow would provide continuous maintenance of the NCG humidity in the reservoir as well as enable a much faster purging process (i.e. removal of moisture from the hot reservoir) if needed, significantly enhancing device�s reliability. The development of hot reservoir VCHP with advanced fluid management features will be presented in this paper, including both numerical and experimental efforts.