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Modeling study of the mechanisms of flame inhibition by CF3Br fire suppression agent
This paper presents the methodology and results of a modeling study undertaken to identify how Halon 1301 (CF3Br) interacts with a flame at the level of elementary reactions. The main purpose is to isolate the chemical kinetics and physical phenomena associated with flame inhibition mechanisms. The specific interest in the study of halons is to further understand how CF3Br functions as an effective flame suppressant so that this information can be used to identify replacement agents. As a result of this work, both the ways in which CF3Br molecules directly participate in flame inhibition and the contributions of the Br and CF3 fragments have been identified. The predominant mechanisms include: (1) trapping of H-atoms diffusing in the direction opposite to the convective flow through the reaction H+CF3Br = CF3+HBr, thus reducing the level of chain branching in the preheat zone, (2) consumption of H-atom through the reaction H+HBr = H2+Br, (3) endothermic cooling of the flame by the unimolecular dissociation of CF3Br, and (4) terminating radicals in the preheat zone by the reaction Br+HO2 = HBr+O2. The efficacy of the various mechanisms is quantitatively ranked by the computed decrease in the laminar flame speed relative to an undoped ethylene/air base case.
Modeling study of the mechanisms of flame inhibition by CF3Br fire suppression agent
This paper presents the methodology and results of a modeling study undertaken to identify how Halon 1301 (CF3Br) interacts with a flame at the level of elementary reactions. The main purpose is to isolate the chemical kinetics and physical phenomena associated with flame inhibition mechanisms. The specific interest in the study of halons is to further understand how CF3Br functions as an effective flame suppressant so that this information can be used to identify replacement agents. As a result of this work, both the ways in which CF3Br molecules directly participate in flame inhibition and the contributions of the Br and CF3 fragments have been identified. The predominant mechanisms include: (1) trapping of H-atoms diffusing in the direction opposite to the convective flow through the reaction H+CF3Br = CF3+HBr, thus reducing the level of chain branching in the preheat zone, (2) consumption of H-atom through the reaction H+HBr = H2+Br, (3) endothermic cooling of the flame by the unimolecular dissociation of CF3Br, and (4) terminating radicals in the preheat zone by the reaction Br+HO2 = HBr+O2. The efficacy of the various mechanisms is quantitatively ranked by the computed decrease in the laminar flame speed relative to an undoped ethylene/air base case.
Modeling study of the mechanisms of flame inhibition by CF3Br fire suppression agent
Casias, C.R. (author) / McKinnon, J.T. (author)
1998
9 Seiten, 13 Quellen
Conference paper
English
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