PDF CALCULATION OF EMISSION NO IN TURBULENT DIFFUSION FLAME WITH GAS AND SOOT RADIATION THERMAL EFFECT

A turbulent pilot flame is numerically simulated considering thermal effect of non-gray gas and soot particles. with CFD code Fluent in this paper. A 41-steps skeletal with extended NO mechanism (SKEL) is used and different combustion models have been adopted to simulate the combustion in turbulence flame. The DO method is employed to solve the radioactive transfer equation. The WSGG model and the Moss-Brookes model are imposed to consider the radiation effect of non-gray gases and soot. The results compared with experimental data of the "Sandia Flame D" published by the international TNF workshops on turbulent flames shows that the C-PDF model with detailed mechanism is able to accurately predict combustion species and even minor mass fraction of OH; the gaseous radiation has a significant effect on temperature and emission (NO). In addition, although soot radiation represents a relatively small portion of the total radiation heat transfer in pilot diffusion flame, it can lead to a drop of peak temperature up to 8K according to simulation. It is suggested that in simulation where soot is prone to produce, soot radiation thermal effect should be taken into account to capture more accurate prediction of NO.