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liquid nitrogen (oxygen simulent) thermodynamic venting system test data analysisIn designing systems for the long-term storage of cryogens in low gravity space environments, one must consider the effects of thermal stratification on excessive tank pressure that will occur due to environmental heat leakage. During low gravity operations, a Thermodynamic Venting System (TVS) concept is expected to maintain tank pressure without propellant resettling. The TVS consists of a recirculation pump, Joule-Thomson (J-T) expansion valve, and a parallel flow concentric tube heat exchanger combined with a longitudinal spray bar. Using a small amount of liquid extracted by the pump and passing it though the J-T valve, then through the heat exchanger, the bulk liquid and ullage are cooled, resulting in lower tank pressure. A series of TVS tests were conducted at the Marshall Space Flight Center using liquid nitrogen as a liquid oxygen simulant. The tests were performed at fill levels of 90%, 50%, and 25% with gaseous nitrogen and helium pressurants, and with a tank pressure control band of 7 kPa. A transient one-dimensional model of the TVS is used to analyze the data. The code is comprised of four models for the heat exchanger, the spray manifold and injector tubes, the recirculation pump, and the tank. The TVS model predicted ullage pressure and temperature and bulk liquid saturation pressure and temperature are compared with data. Details of predictions and comparisons with test data regarding pressure rise and collapse rates will be presented in the final paper.
Document ID
Document Type
Conference Paper
Hedayat, A.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Nelson, S. L.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Hastings, L. J.
(Alpha Technology Huntsville, AL, United States)
Flachbart, R. H.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Tucker, S. P.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
August 23, 2013
Publication Date
January 1, 2005
Subject Category
Fluid Mechanics and Thermodynamics
Meeting Information
Cryogenic Engineering Conference & International Cryogenic Materials Conference(Keystone, CO)
Distribution Limits
Work of the US Gov. Public Use Permitted.