Influence of equivalence ratio on the structure of low-pressure premixed methanolair flames

Abstract

Five low-pressure premixed methanolair flames were analyzed at different equivalence ratios between 0.82 and 1.50. Mole fraction profiles were measured for nine species using a sampling probe/gas ghromatography/electron spin resonance technique. Experimental data were compared with predictions from a one-dimensional flame model using a reduced chemical kinetic mechanism. This mechanism, including only 18 species and 34 pairs of elementary reactions, and the rate constants were in accord with recently recommended values. For the species examined in the five flames, a satisfactory agreement was obtained in shape, magnitude and also in location (except for the lean flame). The removal of CH 3OH was dominated by CH 2OH and HCO reactions, especially their decomposition and consumption by O 2, with fast subsequent production of CH 2O and CO. A reaction path analysis, including the calculation of net reaction rates and the individual contributions of the elementary reactions, is used to interpret the model.