Soot and PAH Formation in Counterflow Diffusion Flames of Ethylene-Propane

Abstract

Sooting characteristics of counterflow ethylene/propane mixture flames have been experimentally studied to investigate the fuel structure effect on PAH and soot formation. Laser-induced incandescene and laser induced fluorescene techniques were employed to measure soot volume fraction and polycyclic aromatic hydrocarbon (PAH) concentration, respectively. Importance of C₃-species on PAH growth as well as the Habstraction-C₂H₂ addition (HACA) mechanism has been emphasized, considering that PAH growth rate is greater for with mixed fuel than for pure fuel flames. It was also con finned that HACA pathways are the dominant soot growth mechanism. A new PAH growth model including both C₂-and C₃-growth mechanisms is proposed based on the experimental results.