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Flame Suppression Effectiveness.


pdf icon Flame Suppression Effectiveness. (5174 K)
Hamins, A.; Gmurczyk, G. W.; Grosshandler, W. L.; Rehwoldt, R. G.; Vazquez, I.; Cleary, T. G.; Presser, C.; Seshadri, K.

NIST SP 861; April 1994.

Evaluation of Alternative In-Flight Fire Suppressants for Full-Scale Testing in Simulated Aircraft Engine Nacelles and Dry Bays. Section 4, Grosshandler, W. L.; Gann, R. G.; Pitts, W. M., Editor(s)(s), 345-465 pp, 1994.

Available from:

Government Printing Office
Order number: SN003-003-03268-9

Keywords:

halons; fire suppression; effectiveness; diffusion flames; turbulent flames; premixed flames; detonation; chain reactions

Abstract:

A flame will be extinguished when the time required for the chain reaction which sustains combustion exceeds the time it takes to replenish the necessary heat and reactants. A characteristic time for reaction can be estimated from the inverse of a global kinetic rate coefficient expressed in Arrhenius form as [equation] where B is a molecular collision frequency factor, Eo is a global activation energy, R is the ideal gas constant, and T is the gas temperature. Assuming reactant species and heat are transported at about the same rate (i.e., unity Lewis number), a characteristic time for replenishing both can be estimated from a convective flow velocity and a length scale by [equation].