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Modeling Analysis for NASA GRC Vacuum Facility 5 UpgradeA model of the VF5 test facility at NASA Glenn Research Center was developed using the direct simulation Monte Carlo Hypersonic Aerothermodynamics Particle (HAP) code. The model results were compared to several cold flow and thruster hot fire cases. The main uncertainty in the model is the determination of the effective sticking coefficient -- which sets the pumping effectiveness of the cryopanels and oil diffusion pumps including baffle transmission. An effective sticking coefficient of 0.25 was found to provide generally good agreement with the experimental chamber pressure data. The model, which assumes a cold diffuse inflow, also fared satisfactorily in predicting the pressure distribution during thruster operation. The model was used to assess other chamber configurations to improve the local effective pumping speed near the thruster. A new configuration of the existing cryopumps is found to show more than 2x improvement over the current baseline configuration.
Document ID
20140013388
Acquisition Source
Glenn Research Center
Document Type
Technical Memorandum (TM)
Authors
Yim, J. T.
(NASA Glenn Research Center Cleveland, OH United States)
Herman, D. A.
(NASA Glenn Research Center Cleveland, OH United States)
Burt, J. M.
(Air Force Research Lab. Cleveland, OH, United States)
Date Acquired
November 6, 2014
Publication Date
February 1, 2013
Subject Category
Ground Support Systems And Facilities (Space)
Systems Analysis And Operations Research
Report/Patent Number
E-18630
GRC-E-DAA-TN6932
NASA/TM-2013-216496
Funding Number(s)
WBS: WBS 182603.01.04.02
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
cryopumping
test facilities
simulation
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