The figures show an instantaneous soot distribution (upper frame) and the average soot distribution (middle) in comparison to the visual impression (photo in lower frame) in a turbulent jet flame (ONERA/DLR). The soot distributions were measured by LII.
Laser-induced incandescence permits quantitative determination of soot volume fractions when the method is calibrated using extinction measurements. Our work is aimed at establishing laser-induced incandescence as a reliable measurement technique for application in turbulent high-pressure combustion like gas turbine combustion chambers. Systematic tests are carried out on high-pressure burners using various fuels, including liquid fuels, in a wide range of stoichiometry and pressures. Evaluating the decay of the LII signal over time permits determination of the primary particle size of the soot produced during combustion.