THE COMPUTATIONAL SIMULATION OF A STOICHIOMETRIC CH2CL2 CH4/AIR FLAT FLAME/

A flat flame simulation was performed to model experimental data from a dichloromethane/methane/air flame. A detailed elementary reaction me chanism was used to carry out the simulation and to obtain insights ab out key chemical processes occurring in various regions of the flame. The flame was at stoichiometric conditions with a Cl/H ratio of 0.34. The PREMIX flat flame program was used to obtain the calculated result s. Comparisons between calculation and experiment were good for the th ree reactants and five of the seven stable intermediates for which exp erimental data were available. Calculated CO2 and CO profiles were als o good, but were found to be offset from experiment by 0.02 cm, with t he calculated profiles occurring too late in the flame. A reaction rat e analysis found that the flame developed in three stages, an initiati on stage, a chlorine inhibited oxidation stage, and finally CO burnout by the reaction CO + OH. The initiation stage was dominated by chlori ne abstraction of H atoms from the fuel species and recombination of d ichloromethyl, chloromethyl and methyl radicals to C-2's. This initiat ion stage was found to occur in the flame at temperatures of 1070 K to 1500 K. The oxidation stage was characterized by temperatures between 1500 K and 1660 K. CO2 formation from CO + OH was found to be inhibit ed in the initiation stage and oxidation stage. Once the temperature r eached 1660 K OH radicals became available through the endothermic rea ctions O + H2O and O + HCl, and CO + OH became the dominant pathway fo r CO2 formation.