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Tri-Gas Pressurization System Testing and Modeling for Cryogenic ApplicationsThe use of Tri‐gas in rocket propulsion systems is somewhat of a new technology. This paper defines Tri‐gas as a mixture of gases composed largely of helium with a small percentage of a stoichiometric mixture of hydrogen and oxygen. When exposed to a catalyst the hydrogen and oxygen in the mixture combusts, significantly raising the temperature of the mixture. The increase in enthalpy resulting from the combustion process significantly decreases the required quantity of gas needed to pressurize the ullage of the vehicle propellant tanks. The objective of this effort was to better understand the operating characteristics of Tri‐gas in a pressurization system with low temperature applications. In conjunction with ongoing programs at NASA Marshall Space Flight Center, an effort has been undertaken to evaluate the operating characteristics of Tri‐gas through modeling and bench testing. Through improved understanding of the operating characteristics, the risk of using this new technology in a launch vehicle propulsion system was reduced. Bench testing of Tri‐gas was a multistep process that targeted gas characteristics and performance aspects that pose a risk to application in a pressurization system. Pressurization systems are vital to propulsion system performance. Keeping a target ullage pressure in propulsions tanks is necessary to supply propellant at the conditions and flow rates required to maintain desired engine functionality. The first component of testing consisted of sampling Tri‐gas sources that had been stagnant for various lengths of time in order to determine the rate at which stratification takes place. Second, a bench test was set up in which Tri‐gas was sent through a catalyst bed. This test was designed to evaluate the performance characteristics of Tri‐gas, under low temperature inlet temperatures, in a flight‐like catalyst bed reactor. The third, most complex, test examined the performance characteristics of Tri‐gas at low temperature temperatures in a test configuration built to more closely resemble a vehicle pressurization system. The results of these bench tests address various risks that all relate to underperformance of Tri‐gas pressurization systems.
Document ID
20140012449
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Taylor, B. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Polsgrove, R. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Stephens, J. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Hedayat, A. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
September 23, 2014
Publication Date
July 28, 2014
Subject Category
Spacecraft Propulsion And Power
Report/Patent Number
M14-3173
Meeting Information
Meeting: AIAA/ASME/SAE/ASEE Joint Propulsion Conference
Location: Cleveland, OH
Country: United States
Start Date: July 28, 2014
End Date: July 30, 2014
Sponsors: American Society for Electrical Engineers, American Inst. of Aeronautics and Astronautics, American Society of Mechanical Engineers, Society of Automotive Engineers, Inc.
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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