Modeling of soot formation and oxidation in turbulent diffusion flames

Abstract

Soot concentration in a turbulent diffusion flame burning propane was predicted using several formation and oxidation models. The Favre-averaged equations governing conservation of mass, momentum, and energy and transport equations for turbulent quantities, mixture fraction and its variance were solved using the k-t model and the laminar flamelet approach. Calculation of soot concentration was performed using the results of the flame field model as input data. The soot formation models of Khan and Greeves, and Moss and co-workers were used together with the soot oxidation models of Magnussen and Hjertager, Lee et al., and Nagle and Strickland-Constable. Comparison of the results with available measurements, and with the predictions obtained by Fairweather et al. using their own soot formation model, shows that reasonable predictions of soot concentration requires an adjustment of the constants of the model of Moss and co-workers. The soot formation model of Fairweather et al. appears to be less sensitive to the constants. The model of Khan and Greeves yields correct orders of magnitude, but fails to predict some important features of the data. Hence, there is a need to improve presently available soot formation and oxidation models to achieve a satisfactory predictive capability.