Chemical Species Profiles of Laminar Propane-Air Flames

The mole fractions of all C-1-C-4 hydrocarbons, CO, CO2, N-2, and O-2 have been measured through the luminous zone and into the post-flame gases of laminar propane-air flames at one atmosphere pressure. The experiments were performed on a flat-flame burner, and samples were withdrawn by an uncooled quartz probe for gas chromatographic analysis. Measurement of the perturbation of the species distributions by the probe sampling technique have been carried out where possible. Concentration-distance profiles have been obtained at three fuel-air equivalence ratios (0.63, 1.0, and 1.46) and at two flame temperatures (1680 and 1880 degrees K) for the fuel-rich equivalence ratio. These results are compared with predicted concentrations obtained by flame model calculations which include extensive chemical reaction mechanism sets. There are deviations of up to a factor of 10 between the predicted and the measured concentrations of certain species. These measurements provide crucial data from which better reaction mechanisms and rate constants can be derived.