Development of a Technique to Determine the Morphology and Dynamics of Agglomerates in Chemically Reacting Flows.

摘要

Analytical and experimental studies for the morphology and dynamics of agglomerated particulates in combustion systems were carried out. The analytical studies entailed the investigation of the validity of the approximate relations for scattering and absorption characteristics as well as predictions of the depolarized light scattering intensities for the agglomerates as functions of primary particle diameter, primary particle number density, scattering angle and optical properties of the particles. The approximate relations were found to be accurate to within 20% or better for agglomerates consisting of Rayleigh size primary particles and with optical properties typical of flame soot. It was found that the agglomerate structures encountered in typical flame systems and other agglomerates composed of metallic or dielectric spheres the reciprocity relations do not hold. Experiments were carried out utilizing latex spheres dispersions in distilled water. The results indicate that multiple scattering within the agglomerate may be the cause for the significant difference (up to 30% or more) of the depolarization ratio from the expected value of 1.0. Soot formation, Particle sizing, Agglomerate characterization, Depolarized light scattering, Reciprocity Relations.