The effect of exit strain rate on soot volume fraction in turbulent non-premixed jet flames

Laser-Induced Incandescence measurements from soot were applied to determine the soot volume fraction (SVF) in three attached turbulent non-premixed jet flames of a similar C2H4-H2-N2 fuel mixture with varying exit strain rate. For all three cases the jet exit Reynolds number was maintained at 15000 while varying both the jet diameter and the fuel exit velocity. Measurements revealed an inverse relationship between the exit strain rate and all of the considered quantities. The probability density functions of maximum instantaneous SVF showed the same trends in terms of exit strain rate although the most probable SVF increased with decreasing exit strain. The volume integrated SVF showed an inverse relationship with the exit strain rate which can be characterized by an exponential fit. A linear correlation was observed between the exit strain rate and the maximum instantaneous SVF the maximum mean SVF and the total soot volume per flow rate of fuel.