Validation and analysis of detailed kinetic models for ethylene combustion
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Present work aims at evaluation of contemporary comprehensive detailed kinetic mechanisms for ethylene combustion, including the Konnov mechanism, LLNL nButane mechanism, San Diego (UCSD) mechanism and USC mechanism. These models have been validated by extensive comparison with available experimental data on ethylene ignition and flame propagation. The experimental data from the literature have been carefully examined to accurately assess the models' predicting performance. Noticeable differences in the predictions of ethylene ignition and flame propagation under a variety of conditions have been observed. Moreover, sensitivity analysis has been conducted to identify important reactions for the prediction of ethylene ignition and flames. For ethylene ignition, it was found that C2H4 consumption reactions with radicals OH, O and subsequent reactions of vinyl with oxygen have dominant effect on predicted ignition delays. The pathway analysis has also been performed for each mechanism to identify different reaction pathways in ethylene ignition process. For ethylene flames, sensitivity analysis shows that H-O and C-1 chemistry reactions significantly influence the laminar burning velocity in lean ethylene/air flames, while C-2 chemistry reactions become of increasing importance in fuel-rich flames. Furthermore, to better understand the models' predicting behavior, the differences in the reaction rate constants and routes of C2H4 and vinyl chemistry have been analyzed and discussed. (C) 2011 Elsevier Ltd. All rights reserved.