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Testing of a Spray-bar Thermodynamic Vent System in Liquid NitrogenTo support development of a microgravity pressure control capability for liquid oxygen, thermodynamic vent system (TVS) testing was conducted at Marshall Space Flight Center (MSFC) using liquid nitrogen (LN2) as a LOX simulant. The spray bar TVS hardware used was originally designed by the Boeing Company for testing in liquid hydrogen (LH2). With this concept, a small portion of the tank fluid is passed through a Joule-Thomson (J-T) device, and then through a longitudinal spray bar mixed-heat exchanger in order to cool the bulk fluid. To accommodate the larger mass flow rates associated with LN2, the TVS hardware was modified by replacing the recirculation pump with an LN2 compatible pump and replacing the J-T valve. The primary advantage of the spray-bar configuration is that tank pressure control can be achieved independent of liquid and vapor location, enhancing the applicability of ground test data to microgravity conditions. Performance testing revealed that the spray-bar TVS was effective in controlling tank pressure within a 6.89 kPa band for fill levels of 90%, 50%, and 25%. Tests were also conducted with gaseous helium (GHe) in the ullage. The TVS operated nominally with GHe in the ullage, with performance similar to the tests with gaseous nitrogen (GN2). Testing demonstrated that the spray-bar TVS design was flexible enough for use in two different propellants with minimal hardware modifications.
Document ID
Document Type
Preprint (Draft being sent to journal)
Flachbart, R. H. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Hastings, L. J. (Alpha Technology Huntsville, AL, United States)
Hedayat, A. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Nelson, S. L. (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 and International Cryogenic Materials Conference(Keystone, CO)
Distribution Limits
Public Use Permitted.
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