Settling Velocity and Density of Monodisperse Aerosols

Abstract

The theory of particles settling in streamline flow in a horizontal tube has been applied to determine the settling velocity and density of a monodisperse aerosol. The aerosol is collected on a filter paper placed in a tube cross section downstream of the inlet. Microscopic examination of the characteristic pattern of the deposited particles on the paper permits a calculation of particle settling velocity and density. Tests of the theory, using monodisperse particles 0.796, 1.305, 1.90, and 2.68 microns in diameter, showed agreement to within 8% or better with settling velocity values calculated from the known size and density of the particles. The theory applies to spheres, cubes, and particles having symmetrical shapes.