Shock and Vibration Tolerant Capillary Two-Phase Loops

Advanced Cooling Technologies, Inc. (ACT), supported by Hamilton Sundstrand, proposes to develop a shock and vibration tolerant Capillary Two-Phase Loop for military vehicle applications. The proposed capillary two-phase loop differs from the traditional loop heat pipes and capillary pumped loops in the evaporator design, which provides inherent tolerance to shock and vibration. Two additional features are added to further improve the shock and vibration tolerance: (1) graded wicks are used in the evaporator to mitigate the shock and vibration impact on the liquid-vapor interface (meniscus); and (2) check valves are used in the liquid transport line to mitigate the macro-scale liquid churning motion. The Phase I project will verify the basic concept of combining graded wick evaporator with liquid check valves to achieve improved shock and vibration tolerance. A proof-of-concept capillary two-phase loop using water as the working fluid will be designed, fabricated and tested at Mil-Spec shock and vibration conditions for Army vehicles. The Phase II project will design, fabricate and test full scale capillary two-phase loops under startup and transient heat loading as well as Mil-Spec shock and vibration conditions. The follow on Phase III project will integrate the technology in actual vehicles and conduct qualification tests in simulated operational environments.