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Thermosyphon Flooding Limits in Reduced Gravity EnvironmentsFission Power Systems have long been recognized as potential multi-kilowatt power solutions for lunar, Martian, and extended planetary surface missions. Current heat rejection technology associated with fission surface power systems has focused on titanium water thermosyphons embedded in carbon composite radiator panels. The thermosyphons, or wickless heat pipes, are used as a redundant and efficient way to spread the waste heat from the power conversion unit(s) over the radiator surface area where it can be rejected to space. It is well known that thermosyphon performance is reliant on gravitational forces to keep the evaporator wetted with the working fluid. One of the performance limits that can be encountered, if not understood, is the phenomenon of condenser flooding, otherwise known as evaporator dry out. This occurs when the gravity forces acting on the condensed fluid cannot overcome the shear forces created by the vapor escaping the evaporator throat. When this occurs, the heat transfer process is stalled and may not re-stabilize to effective levels without corrective control actions. The flooding limit in earth's gravity environment is well understood as experimentation is readily accessible, but when the environment and gravity change relative to other planetary bodies, experimentation becomes difficult. An innovative experiment was designed and flown on a parabolic flight campaign to achieve the Reduced Gravity Environments (RGE) needed to obtain empirical data for analysis. The test data is compared to current correlation models for validation and accuracy.
Document ID
20130000427
Document Type
Presentation
Authors
Gibson, Marc A. (NASA Glenn Research Center Cleveland, OH, United States)
Jaworske, Donald A. (NASA Glenn Research Center Cleveland, OH, United States)
Sanzi, James L. (Sest, Inc. Middleburgh Heights, OH, United States)
Ljubanovic, Damir (Gilcrest Corp. Cleveland, OH, United States)
Date Acquired
August 27, 2013
Publication Date
July 30, 2012
Subject Category
Astrophysics
Report/Patent Number
E-18221-1
Meeting Information
International Energy Conversion Engineering Conference(Atlanta, GA)
Funding Number(s)
WBS: WBS 887359.01.04
Distribution Limits
Public
Copyright
Public Use Permitted.

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