The Influence of Gravity Levels on Soot Formation for the Combustion of Ethylene-Air Mixture

The reduced mechanism coupled with 2D flame code using CHEMKIN II to investigate the effect of gravity on flame structure and soot formation in diffusion flames. The results show that the gravity has a rather significant effect on flame structure and soot formation. The visible flame height and peak soot volume fraction in general increases with the gravity from 1g decreased to 0g. The peak flame temperature decreases with decreasing gravity level. Comparing the calculated results from 1g to 0g, the flame shape becomes wider, the high temperature zone becomes shorter, the mixture velocity has a sharp decrease, the soot volume fraction has a sharp increase and CO and unprovided species distribution becomes wider along radial direction. At normal and half gravity, the flame is buoyancy controlled and the axial velocity is largely independent of the coflow air velocity. At microgravity (0g), the flame is momentum controlled.