Working Fluid Trade Study for a Two-Phase Mechanically Pumped Loop Thermal Control System



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48th International Conference on Environmental Systems


NASA is constantly looking at novel mission designs capable of giving greater science returns with lower cost, mass, and power budgets. One such enabling technology is a 2-phase thermal control system capable of providing stability in highly variable thermal environments, with the added benefit of reducing mass and power. 2-Phase mechanically pumped fluid systems are hybrid solutions for thermal control that overcome some limitations typical of heat pipes and single phase systems. They have less sensitivity to pressure drops compared to capillary based heat pipes, which allow for longer lines, smaller pipe diameters and multiple evaporators and condensers. Furthermore, if compared with single phase systems, they accommodate high heat fluxes, require a minimal temperature delta to transfer heat, and allow a high degree of isothermicity. This paper presents a working fluid trade study necessary to optimize the performances of this thermal control system that combines heat pipes and single phase loop principles. New constraints and boundaries driven by the system components have been defined to allow optimal operational points and robustness. The high level model developed in this research accounts for the working mechanism and the system dynamics to rate the performance of the fluids from the REFPROP database. The selection of the working fluid from the final candidates highlighted by the model was made considering cost, hazardous properties, and heritage in previous applications.


Stefano Cappucci, Jet Propulsion Laboratory
Ben Furst, Jet Propulsion Laboratory
Eric Sunada, Jet Propulsion Laboratory
Pradeep Bhandari, Jet Propulsion Laboratory
Takuro Daimaru, Jet Propulsion Laboratory
ICES201: Two-Phase Thermal Control Technology
The 48th International Conference on Environmental Systems was held in Albuquerque, New Mexico, USA on 08 July 2018 through 12 July 2018.


2 phase, MPFL, fluid trade study, two phase mechanically pumped loop, thermal control, technology development