Description: NASA’s future remote sensing science missions require advanced thermal management technologies to maintain multiple instruments at very stable temperatures and utilize waste heat to keep other critical subsystems above minimum operational temperatures. Two-phase pumped loops are an ideal solution for these applications. A critical need for these pumped loops is a microgravity-compatible evaporator having a large cooling area to maintain the temperatures of multiple electronics and instruments. The evaporator must be able to accommodate multiple heat loads with a wide range of heat flux densities and allow heat loads to be mounted on any available locations of its cooling surfaces to facilitate vehicle-level system integration. To this end, Creare proposes to develop a lightweight, compact evaporator with innovative internal design features to adaptively distribute liquid refrigerant to heated areas, preventing dryout in areas with high heat flux. This advanced flow distribution feature reduces liquid recirculation flow in the pumped loop and thus the system power input. The design features also provide strong internal structural support for the evaporator, reducing the size and mass of the evaporator cover plates. In Phase I, we proved the feasibility of the evaporator by developing a preliminary evaporator design, predicting its overall performance, and demonstrating its key performance features and fabrication processes by testing. In Phase II, we will optimize the evaporator design, fabricate a 0.5 m x 0.5 m evaporator, demonstrate its steady state and transient performance in a representative pumped loop, and deliver it to NASA JPL for further performance evaluation.

Benefits: The proposed evaporator will enable reliable two-phase pumped loops for efficient and precision thermal control of critical instruments in remote sensing science satellites and exploration vehicles, including a future mission to Saturn's moon Enceladus and the Surface Water and Ocean Topography (SWOT) mission. The evaporator technology also has applications in future two-phase thermal management systems for rovers and habitats.

The evaporator technology has applications in advanced two-phase thermal management systems for commercial and military satellites, aircraft, terrestrial cooling systems for electronics and laser systems, hybrid vehicle power electronics, and computer servers.