FRACTAL DIMENSION AND AEROSOL-PARTICLE DYNAMICS

Starting from the basic scaling relation between the number of particles in a fractal aggregate and its extension in space, I develop expressions for the aerodynamic and volume equivalent diameters in terms of the primary particle diameter and density, the extension of the aggregate in space, and it's fractal dimension. Expressions are derived for the velocities of such fractal aggregates in thermal, gravitational, electrical, and acoustical fields. A procedure is proposed to obtain the fractal dimension from a comparison of the geometric and aerodynamic distribution functions.