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Storage and Discharge Characteristics of Halon Alternatives.

pdf icon Storage and Discharge Characteristics of Halon Alternatives. (882 K)
Yang, J. C.; Cleary, T. G.; Vazquez, I.; Boyer, C. I.; King, M. D.; Breuel, B. D.; Grosshandler, W. L.; Huber, M. L.; Weber, L.

Alliance for Responsible Atmospheric Policy; U.S. Environmental Protection Agency; Environment Canada; United Nations Environment Programme; U.S. Department of Agriculture. Stratospheric Ozone Protection for the 90's. 1995 International CFC and Halon Alternatives Conference and Exhibition. Proceedings. October 21-23, 1995, Washington, DC, 594-603 pp, 1995.


Federal Aviation Administration, Washington, DC


halon alternatives; aircraft fires; dry bays; discharge; halons; pipes; sprays; thermophysical properties


Three important issues regarding the use of halon alternatives for in-flight fire protection applications were studied as part of the current halon alternative research program at the National Institute of Standards and Technology (NIST): (1) the conditions inside the vessel at different ambient temperatures before discharge, (2) the discharge of the contents into a confined space, and (3) the distribution of the agent/nitrogen mixture in piping systems. The first issue addresses the resultant pressure inside the vessel before discharge. Such information dictates the vessel structural integrity and subsequent discharge behavior of the agent/nitrogen mixture. The second deals specifically with military aircraft dry bay fire protection, and the third concerns general (commercial and military) aircraft engine nacelle fire protection applications. To establish the internal vessel conditions, the effects of fill density, initial nitrogen pressure, and ambient temperature were studied. For the discharge of agent/nitrogen mixture into a confined space, the effects of vessel geometry, initial nitrogen pressure, fill density, initial vessel temperature, discharge mechanism, discharge orientation, and orifice size were examined. For the distribution of agent/nitrogen mixture in piping systems, the effects of initial nitrogen pressure, fill density, initial bottle temperature, and piping geometries (sudden pipe expansion and contraction, different piping diameters, tees, and elbows) on the two-phase flow behavior were explored. Experimental results and model predictions will be presented and discussed for each issue.