Effects of aromatic chemistry-turbulence interactions on soot formation in a turbulent non-premixed flame

In this paper, Large Eddy Simulations (LES) have been performed on an ethylene/air piloted turbulent non-premixed sooting jet flame to quantify the importance of aromatic chemistry-turbulence interactions. Aromatic species are of primary importance since their concentrations control directly the soot nucleation rates. In the current work, the chemistry-turbulence interactions for benzene and naphthalene are taken into account by solving transport equations for their mass fractions. A recently developed relaxation model is used to provide closure for their chemical source terms. The effects of turbulent unsteadiness on soot yield and distribution are highlighted by comparing the LES results with a separate LES using tabulated chemistry for all species including the aromatic species. Results from both simulations are compared to experimental measurements. Overall, it is shown that turbulent unsteady effects are of critical importance for the accurate prediction of not only the inception locations, but also the magnitude and fluctuations of soot. (C) 2014 The Combustion Institute. Published by Elsevier Inc. All rights reserved.