Motion of Fractal-Like Aggregates: Particle Settling Velocity and Thermophoresis

Abstract

A theoretical approach to calculation of the parameters of fractal-like aggregates based on gas-kinetic results for homogeneous spheres is presented. The essence of the approach consists in the replacement of a real fractal aggregate by a sphere equivalent in mobility and approximation of the aggregate density and thermal conductivity by their effective values. The effectiveness of the approach has been confirmed in comparison with known experimental data. It has two important restrictions: a fractal aggregate should consist of a great number of primary particles (100 and more), and primary particles should be monodisperse. Violation of these conditions leads to considerable divergence between theoretical and experimental results.