Quantitative Chemical Mechanism for Heterogeneous Growth of Soot Particles in Premixed Flames

Abstract

In this article we present the first quantitative chemical mechanism for the heterogeneous growth of soot particles in premixed flames. We have found that the increased surface growth rate in sootier (richer) flames is due primarily to an increase in the surface area available for growth; the concentration of the gas phase growth species is similar from flame to flame. Growth decreases as the soot ages in the flame, but this is due to a decrease in the reactivity of the soot and not to a depletion of growth species. Acetylene supplies nearly all of the mass for soot growth, and our data suggest that soot growth can be understood in terms of a first order decomposition reaction of acetylene on the soot surface.