Pressure effect on soot formation in turbulent diffusion flames

Soot formation in a methane-air turbulent jet diffusion flame is investigat ed numerically using a semi-empirical model. The temperature, density and s pecies (the soot precursor C2H2) fields are calculated using detailed chemi cal kinetic mechanism based on the flamelet library approach. The influence of pressure on the soot formation and the behavior of the semi-empirical m odel in different flame situations are investigated. It is found that the f lame shape and the flame temperature can be well predicted by the flamelet library approach. The calculated soot yield is mostly sensitive to the soot surface growth rate and the increase of pressure. The increase of pressure leads to the increase of soot surface growth rate and therefore to the inc rease of soot volume fraction. By adjusting a model constant in the soot su rface growth rate, the soot emissions in both pressure p = 1 atm and p = 3 atm are properly simulated by the current semi-empirical soot model. (C) 20 01 Elsevier Science Ltd. All rights reserved.