INHIBITION OF A FUEL LEAN ETHYLENE AIR FLAME IN A JET STIRRED COMBUSTOR BY METHYL-CHLORIDE - EXPERIMENTAL AND MECHANISTIC ANALYSES

Probability density functions (PDFs) of instantaneous temperature have been obtained for fuel lean C2H4/air burning in a toroidal jet stirred combustor (TJSC) using pulsed laser Rayleigh scattering. The PDFs provide a very sensitive measure of departures from perfectly stirred reactor (PSR) behavior. Narrow PDFs were obtained under stable operating conditions. As the mean combustion temperature was reduced or the reaction kinetics decelerated by the addition of CH3C1, the PDFs exhibited a bimodal distribution indicative of localized blowout. Modeling of the reactions indicates that chlorine primarily destabilizes this hydrocarbon oxidation system by inhibiting the burnout of CO. This inhibition is affected through significant depletion of OH in the presence of relatively high levels of HC1 by the reaction OH + HC1 = H2O + Cl. Inhibition is further affected by the termination reaction Cl + HO2= HC1 + O2because HO2is a source of OH. © 1990, Taylor & Francis Group, LLC. All rights reserved.