Fluid Line Evacuation and Freezing Experiments for Digital Radiator Concept

Freezable radiators offer an attractive solution to the issue of thermal control system scalability. As thermal environments change, a freezable radiator will effectively scale the total heat rejection it is capable of as a function of the thermal environment and flow rate through the radiator. Scalable thermal control systems are a critical technology for spacecraft that will endure missions with widely varying thermal requirements. These changing requirements are a result of the space craft's surroundings and because of different thermal rejection requirements during different mission phases.However, freezing and thawing (recovering) a radiator is a process that has historically proven very difficult to predict through modeling, resulting in highly inaccurate predictions of recovery time. To attempt to improve this, tests were conducted in 2009 to determine whether the behavior of a simple stagnating radiator could be predicted or emulated in a Thermal Desktop™ numerical model. A 50-50 mixture of DowFrost HD and water was used as the working fluid. Efforts to scale this model to a full scale design, as well as efforts to characterize various thermal control fluids at low temperatures are also discussed.Previous testing and modeling efforts showed that freezable radiators could be operated as intended, and be fairly, if not perfectly predicted by numerical models. This paper documents the improvements made to the numerical model, and outcomes of fluid studies that were determined necessary to go forward with further radiator testing.

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Fluid Line Evacuation and Freezing Experiments for Digital Radiator Concept

Cited by 3 publications

References 14 publications

Effect of Gravity on Ice-Layer Growth in a Freezable Heat Exchanger

Effect of Gravity on Ice-Layer Growth in a Freezable Heat Exchanger

Design and Modeling of a Radiator with Digital Turn-Down Capability under Variable Heat Rejection Requirements

Freezable Radiator Model Correlation Improvements and Fluids Study

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