Detailed Modeling and Analysis of Aromatic Additive Effects in Ethylene-Air Flames

摘要

Ethylene-air flames are being studied to determine the effects of small amounts of stable aromatic intermediates on the combustion chemistry as it relates to the formation of soot. We show that the introduction of aromatics into the transition regime between a well-stirred and plug flow reactor can trigger the formation of larger aromatics at various concentrations, providing information concerning the gas phase chemistry during soot inception. Gas chromatography is performed on combustion samples extracted from the plug flow reactor at known residence times for a given flame equivalence ratio and additive concentration. The additives studied include benzene and ethylbenzene. For these additives, the results show that the smaller ring compounds achieve steady state between ring formation and expansion. As residence times increase, higher molecular weight molecules are formed at higher concentrations in comparison to baseline data were no additive is introduced. This body of work provides experimental data which will be useful in the expansion of the range of conditions used to validate and "fine tune" existing PAH/Soot models.