Self-Ignition and Pyrolysis of Acetone behind Reflected Shock Waves

Abstract

Abstract The self-ignition of a stoichiometric acetone−oxygen mixture diluted with argon was studied both experimentally and numerically. The experiments were performed behind reflected shock waves over a temperature range from 1280 to 1810 K at a total gas concentration of [M]50 ≈ 10−5 mol/cm3. The process was monitored by recording the signals of absorption by methyl radicals (λ = 216.5 nm) and emission from electronically excited OH* radicals (λ = 308 nm) and CO2* molecules (λ = 370 nm). Numerical simulations within the framework of various detailed kinetic mechanisms were performed to reproduce our own and published experimental data on the pyrolysis and self-ignition of acetone behind reflected shock waves, including the concentration profiles of acetone and CH3 in the ground state and electronically excited OH* and CO2*, as well as the temperature dependence of the self-ignition delay time. It has been established that various detailed kinetic mechanisms describe the kinetic characteristics of the pyrolysis of acetone in shock waves with varying degrees of accuracy. At the same time, all of them predicted the measured ignition delays within a factor of two. A sensitivity analysis showed that the reactions determining the pyrolysis of acetone produce only a slight effect on the branched-chain ignition process, so that the relevant rate constants only slightly affect the ignition delay time.