The kinetic modeling of soot precursors in a butadiene flame

A comprehensive, semidetailed kinetic scheme, describing hydrocarbon oxidation has been applied to the simulation of a premixed, rich, nearly sooting, butadiene, laminar dame. The main goal of this work was to understand the mechanism and to validate a general detailed kinetic model for the prediction of both polycyclic aromatic hydrocarbons (PAHs) and soot precursors from the pyrolysis and oxidation of butadiene. The modeling computations are in quite good agreement with the experimental measurements. Under these conditions, butadiene: undergoes particular pathways involving resonantly stabilized radicals. Molecular reactions explain almost all the consumption of butadiene during its pyrolysis, while the additions on double bonds are of great importance in explaining the formation of the first aromatic rings, and, consequently, of PAHs. Kinetic analysis allows identification of the radical C4H5 as being the major contributing factor in the initial formation of benzene and naphthalene. Several combustion byproducts and radicals are quite well simulated by the model, although important discrepancies in the prediction of CH4 were found. To extend the validity of the developed scheme and to build up a better understanding of the role of different reaction paths, the kinetic model for butadiene was also compared with measurements of both oxidation in jet-stirred and plug flow reactors at intermediate temperatures, and of pyrolysis ina shock tube at high temperatures. (C) 2000 by The Combustion Institute.