A Study of the Chemiluminescence of СН*, ОН*, С2*, and СО2* During the Ignition of C2H2/O2/Ar Mixture Behind Reflected Shock Waves

The self-ignition of a number of near-stoichiometric acetylene−oxygen mixtures diluted with argon are experimentally and computationally studied to gain additional insights into the nature of the chemiluminescence that accompanies this process and to obtain some of its quantitative characteristics. The experiments are performed behind reflected shock waves at temperatures of 1270–1820 K and a pressure of ∼1 bar. The time evolution of the intensity of the luminescence of the electronically excited C2*, CH*, and OH* radicals and CO2* molecule is concurrently monitored. The measured temperature dependences of the ignition delay time are demonstrated to be in satisfactory agreement with the published data and the results of simulations within the framework of our own and a number of published mechanisms. To achieve a better description of the behavior of CO2* and C2*, and to improve the agreement between the experimental data and the results of kinetic simulation of CO2*, a novel kinetic mechanism wherein the reaction СН2 + О2 = СО2* + Н + Н is replaced by the reaction СН + О2 = СО2* + Н has been proposed.