Kinetic effects of methyl radicals on PRF lean ignition: a comparative study of skeletal mechanisms

Despite considerable achievements of combustion kinetics, the chemical kinetic impacts of trace promoting species on practical fuel combustion has been hitherto handled seperately either as ignition or extinction-related effects, overlooking the impact of the extinction process on re-ignition kinetics. We herein demonstrate the applicability of oscillatory stirred reactor configuration to quantify the combined impacts of the methyl radical on ignition/extinction of primary reference fuels (PRF) in stoichiometric and ultra-lean conditions, thereby complementing steady-state configurations for kinetic mechanism validation. A new convenient reactivity metric is proposed based on the matching of temperature Fourier spectrum of additivated fuels with corresponding PRF. Using a new skeletal mechanism obtained from calibration on a variety of ignition experiments, we characterize ignition regimes by CEMA analysis and highlight the key reactions of the C1-C3 reaction subsets that should be included in minimal skeletal mechanisms used in reactive CFD modeling to properly describe re-ignition phenomena over a variety of new combustion applications involving methyl radical injection.