Stirred-Reactor Simulations of Enhanced Reaction in the Presence of Fire Suppressants
Gregory T. Linteris, Donald R. Burgess Jr., Fumiaki Takahashi, Viswanath R. Katta, Oliver Meier
Several agents are under consideration to replace CF3Br in suppressing aircraft cargo bays fires. In a Federal Aviation Administration performance test simulating the explosion of an aerosol can, however, the replacements, when added at sub-inerting concentrations, have all been found to create higher final pressure than with no agent, hence failing the test. Thermodynamic equilibrium calculations, as well as perfectly-stirred reactor simulations with detailed reaction kinetics, are performed to understand the unexpected phenomena. The pressure rise with added C2HF5 or C3H2F3Br is shown to be dependent upon the amount of added agent, and can only occur if a large fraction of the available oxidizer in the chamber is consumed, corresponding to near-stoichiometric proportions of fuel, oxygen, and agent. Conversely, due to the unique stoichiometry of CF3Br, this agent is predicted to cause no increase in pressure, even in the absence of chemical inhibition. For CF3Br, stirred-reactor simulations predict that the inhibition effectiveness is highly dependent upon the mixing conditions of the reactants (which affects the local stoichiometry and hence the overall reaction rate). For C2HF5, however, the overall reaction rate was only weakly dependent upon stoichiometry, so the fuel-oxidizer mixing has less effect on the suppression effectiveness.
2011 Fall Technical Meeting for the Eastern State Section of the Combustion Institute
October 9-12, 2011
Fire Suppression, Aircraft Fire Suppression, CF3Br, Halon replacements, fire suppression, flame inhibition
, Burgess, D.
, Takahashi, F.
, Katta, V.
and Meier, O.
Stirred-Reactor Simulations of Enhanced Reaction in the Presence of Fire Suppressants, 2011 Fall Technical Meeting for the Eastern State Section of the Combustion Institute, Storrs, CT
(Accessed March 5, 2024)