The effect of oxygen enrichment on incipient soot particles in inverse diffusion flames

► We examine changes in oxygen concentration in the oxidizer in inverse diffusion flames, and investigate the soot formation of incipient soot particles. Laser diagnostics such as OH, PAHs-PLIF and soot scattering technique showed the flame structure according to the oxygen enrichment. Two-color pyrometry showed that temperature along the soot growth line maintained between 2000 and 2200 K. The oxygen enrichment resulted in moving the beginning of the yellow flame. C/H ratios of soot particles linearly increased with increasing residence time, and incipient soot particles from inverse diffusion flames were carbonized gradually.