Soot study in laminar diffusion flames at elevated pressure using two-color pyrometry and Abel inversion

Soot temperatures were measured using a two-color pyrometry and an Abel inversion technique in co-flow diffusion flames at pressures up to 0.4 MPa. The measured soot temperatures are analyzed along with the soot volume fractions. The oxidation of soot particles ceased at the temperature close to 1400 K. The addition of small amount of air into ethylene does not change the temperature in soot formation regions. The added propane (up to chi (C3H8)=0.27) increases the soot volume fraction without changing soot temperatures in ethylene-propane mixture flames. These results support that the enhanced C3H3 recombination reaction for incipient ring formation is the major contribution for the increase of soot volume fraction and the synergistic effect. The radial profiles of soot temperature are calculated from the line-of-sight soot emission data through an Abel inversion procedure. The effective soot particle brightness temperature is not simply weighted toward the regions of highest soot loading.