Revealing the doping effects of C2H6O isomers on a benzene flame: An experimental and modeling study

Chemical structures of six laminar premixed ethanol- and dimethyl ether (DME)-doped benzene flames were investigated at the pressure of 30 Torr with the carbon/oxygen (C/O) ratio maintained at 0.7. Dozens of flame species including some reactive radicals and aromatics were identified and quantified with the technique of synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS). A kinetic model was constructed by combining our previous benzene model with sub-mechanisms for ethanol and DME. The model was tested with the current speciation measurements, showing satisfactory predictive performances. Based on the rate of production (ROP) analyses, the pathways for fuel decompositions and the aromatics growth were revealed. Compared to the neat benzene flame, the higher concentrations of monocyclic aromatic hydrocarbons (MAHs) in doped flames are due to the higher production of C1 and C2 hydrocarbons from the consumptions of oxygenated additives. While the formation of polycyclic aromatic hydrocarbons (PAHs) is inhibited, which results from the reduced formation of phenyl, C3 and C5 species.