MORPHOLOGICAL CHANGE OF HARDENED OIL PARTICLES INDUCED BY IMPACTION AGAINST A SOLID-SURFACE

The morphological change of fine particles induced by impaction agains t a solid surface has been investigated for two types of tristearin fi ne particles which have different mass median diameters. It is found t hat the bulk density of the heap formed on the solid surface increases with increasing the impaction velocity and the mass median diameter o f the tested powder. The change in the bulk density can be evaluated b y the effective impaction load which is calculated by the theory of el asticity, considering the particle size distribution and the mechanica l properties of particles. The heap formed on the solid surface at low impaction load consists of fine particles, while at high impaction lo ad, it consists of a caked heap where no particles are found. (C) 1997 American Association for Aerosol Research.