Application of an Optical Diagnostic (LII/ELS) to Measure Soot Formation Trends within Turbulent Buoyant Non-Premixed Flames

Flaring in the upstream oil and gas industry generates black carbon, which adversely affects human health and is an important positive climate forcer. Experiments were performed to investigate soot formation and oxidation within these large, flare-type, turbulent, non-premixed, buoyant flames. Simultaneous spatially-resolved auto-compensating Laser-Induced Incandescence and Elastic Light Scattering was used to measure the instantaneous soot volume fraction (fv), primary particle diameter (dp), and mean aggregate radius of gyration (Rgm1) of soot. Measurements were completed on two comparable turbulent buoyant flames emanating from a 50.8 mm diameter pipe with and without an internal turbulence-generating grid. Centreline profiles of fv, dp, and Rgm1 are presented with uncertainties obtained via Monte Carlo analysis. For the conditions investigated, internal pipe turbulence has only a minor effect on the soot formation trends within the flame, suggesting that internal turbulence is likely less important than other factors when modelling soot formation in flare flames.