High-temperature oxidation of acetylene by N2O at high Ar dilution conditions and in laminar premixed C2H2 + O2 + N2 flames

High-temperature oxidation of acetylene (C2H2) is studied behind reflected shock waves and in laminar flames. Atomic resonance absorption spectroscopy (ARAS) is employed to record oxygen atom concentration profiles for the mixture of 10 ppm C2H2 + 10 ppm N2O + argon and temperatures from 1688 K to 3179 K, extending the range of such data available from the literature. Laminar burning velocity of C2H2 in a diluted oxidizer with 11-13% O-2 in the O-2 + N-2 mixture is measured using the heat flux method and compared to the literature data for the 13% O-2 mixture. An updated detailed kinetic mechanism is presented to model and analyze the results, and the selection of rate constants in the C2H2 sub-mechanism, whose importance was identified by the sensitivity analysis, is discussed. The performance of the new model is compared against several reaction schemes available from the literature, and kinetic differences between them are outlined. The new shock-wave data helped to improve the performance of the present model compared to its previous version. For the laminar flames, a particular importance of reactions involving C2H3 is identified, however, the reasons for the observed differences in model predictions are to a large extent located outside the C2H2 sub-mechanism, which were also identified. (C) 2021 The Author(s). Published by Elsevier Inc. on behalf of The Combustion Institute.

Automated summary

High-temperature oxidation of acetylene was studied using ARAS to analyze oxygen atom concentration profiles and conduct kinetic modeling. The selection of rate constants in the C2H2 sub-mechanism was found to significantly impact model performance, and non-C2H2 related reactions were identified to also influence model predictions.