Demonstration of heat switch function of loop heat pipe with electrohydrodynamic pump

Abstract

Loop-Heat-Pipes (LHPs) are promising for cooling of electric devices in spacecraft. However, the LHP operation must be shut down in some cases (e.g., lunar rover on cold nights) to avoid overcooling or reduce heater energy consumption. In this study, we placed an electrohydrodynamic (EHD) conduction pump in the liquid line of the LHP, which operates against the normal LHP flow. The pressure generated by the EHD pump overcomes the capillary pressure developed in the evaporator, then LHP operation stops. An EHD conduction pump was developed and evaluated to demonstrate our approach. As a result, the LHP was shutdown successfully when an appropriate high voltage was applied to the EHD pump, and the shutdown continued until applied voltage to EHD pump has decreased.