The effect of soot particle optical inhomogenity and agglomeration on the analysis of light scattering measurements in flames

Computations have been performed for homogeneous and radially inhomogeneous spheres plus agglomerated structures composed of spherical primary units. The ranges of refractive index and particle size considered are typical of soot in flames. The effects of uncertainty in the refractive index and neglect of its radial distribution on inferring spherical particle sizes and concentrations from in situ light-scattering measurements are delineated. A framework is established for computing various scattering characteristics of agglomerated particles in terms of the scattering functions for spherical particles. The results achieved for agglomerates indicate that mean values of the particle concentration, number of units in an agglomerate and overall agglomerate size may be inferred from light-scattering data.