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Suppression of Ignition Over a Heated Metal Surface.


pdf icon Suppression of Ignition Over a Heated Metal Surface. (880 K)
Hamins, A.; Borthwick, P.

Combustion and Flame, Vol. 112, No. 1/2, 161-170, January 1998.

Keywords:

fire research; halogenated compounds; ignition; ignition suppression; ignition temperature

Abstract:

The effectiveness of various agents including N2, C3HF3, C3HF7, CF3Br and CF3I was compared in suppressing the ignition of stoichiometric mixtures of methane/air, propane/air, and ethene/air. Measurements were made of the critical ignition temperature of the reactants as they flowed over a heated nickel surface. The results showed that CF3Br and CF2I were both hihgly effective suppressants of ignition for all fuels studied. This was not the case for N2, C2HF5, and C3HF7, which tended to have little effect on ignition unless very high agent concentrations were present, when ignition was not achieved. The effect of the average reactant velocity and the angle of approach of the reactants (relative to the heated metal surface) on the critical ignition temperature for stoichiometric ehtne/air mixtures flowing over the heated nickel foil were also measured.