Chemical structure of atmospheric pressure premixed n-decane and kerosene flames

This study was aimed at comparing the chemical structure of two rich premixed dames fed respectively with a neat fuel : n-decane and a multi-component fuel, kerosene. Both flames were stabilized on a flat-flame burner at atmospheric pressure. Samples were withdrawn along the symmetry axis with a quartz microprobe and analyzed by gas phase chromatography. The main objective was to justify, for a future modelling purpose, the use of a detailed reaction mechanism validated in the n-decane flame to predict the chemical structure of a kerosene flame. A close similitude was observed for the mole fraction profiles of both major species and main intermediates measured in each flame. Relative concentrations of the intermediate species in the n-decane flame can be interpreted qualitatively by beta-scission of large alkyl radicals. The only marked difference observed when changing the fuel concerns benzene. The maximum mole fraction measured in the kerosene flame : 1.05 . 10(-3) exceeds by one order of magnitude, the maximum value obtained in the n-decane dame: 6.5 . 10(-5). This result confirms the conclusions drawn from a previous study of n-decane and kerosene flames stabilized at low pressure (6 kPa). Since the concentrations of the intermediate species involved in the formation of benzene are within the same range in both the fuels, it is inferred that the additional benzene results from reaction of the aromatic component of the kerosene fuel.