Experimental and Chemical Kinetics Study of the Effects of Halon 1211 (CF2BrCl) on the Laminar Flame Speed and Ignition of Light Hydrocarbons

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• 作者：Olivier Mathieu ; Charles Keesee ; Claire Gregoire ; Eric L. Petersen
• 刊名：Journal of Physical Chemistry A
• 出版年：2015
• 出版时间：July 16, 2015
• 年：2015
• 卷：119
• 期：28
• 页码：7611-7626
• 全文大小：789K
• ISSN：1520-5215

文摘

In this study, the effect of Halon 1211 (CF₂BrCl) on the ignition delay time and laminar flame speed of CH₄, C₂H₄, and C₃H₈ were investigated experimentally for the first time. The results showed that the effects of Halon 1211 on the ignition delay time are strongly dependent on the hydrocarbon: the ignition delay time of CH₄ is significantly decreased by Halon 1211 addition, while a significant increase in the ignition delay time was observed with C₂H₄ for the lowest temperatures investigated. Ignition delay times for C₃H₈ were slightly increased, mostly on the low-temperature side and for the fuel-rich case. A significant reduction in the laminar flame speed was observed for all of the fuels. A tentative chemical kinetics model was assembled from existing models and completed with reactions that have been determined in the literature or estimated when necessary. The experimental results were reproduced satisfactorily by the model, and a chemical analysis showed that most of the effects of Halon 1211 on the ignition delay times of C₂H₄ and C₃H₈ are due to the consumption of H radical through the reaction HBr + H 鈬?Br + H₂. In the case of methane, the CF₂ radical promotes the formation of H via CF₂ + CH₃ 鈬?CH₂:CF₂ + H, which then promotes the branching reaction H + O₂ 鈬?OH + O. The laminar flame speed results can be explained using catalytic cycles involving Br atoms that are similar to those reported in the literature for CF₃Br. This study exhibits the need for a better estimation of the chlorine atom chemistry during the combustion of hydrocarbons in the presence of fire suppressants.