Soot processes in a strongly radiating turbulent flame from laser scattering/extinction experiments

Soot formation within a highly luminous turbulent non-premixed flame burning acetylene in air was investigated by conducting laser scattering and extinction experiments. Mean soot volume fractions, spherule diameters, and aggregate sizes were exclusively characterized based on an optical interpretation that can properly account for the actual particulate morphology. This allowed decoupling of surface growth and oxidation from the unavoidable aggregation process and therefore provided accurate descriptions of turbulent soot dynamics. The present experiments broadened the database in a lightly sooting ethylene flame previously considered so that the effects of fuel type on particle evolution within turbulent flames could be explored. The relatively high particle concentrations in the acetylene flame also offered conditions that are encountered in many practical combustors operating at elevated pressures, e.g. diesel engines. The findings reported here are relevant not only to developing computational models for accurate predictions of radiative transfer but also to controlling pollutant emissions from combustion systems.