Soot formation in turbulent non premixed flames

A coupled radiation/flamelet combustion model is applied to the simulation of a turbulent diffusion flame fed with natural gas. The major species and temperature fields are calculated using the Steady Laminar Flamelet and the Eddy Dissipation Concept models. The formation of soot particles is predicted using the method of moments (MOM), coupled with simple semi-empirical models of soot nucleation, growth, oxidation and aggregation. The interaction of turbulence and soot chemistry is described by a probability density approach based on the laminar flamelet formulation. The scope of this work is mainly to investigate the accuracy and reliability of available soot semi-empirical models by comparison with experimental data in turbulent flames. Particular attention is devoted to the effects of turbulent fluctuations on the closure of soot source terms in the moment equations. The predicted soot amount in the turbulent flame investigated is found relatively insensitive to the nucleation models. On the contrary, growth and oxidation models significantly influence soot formation.