Direct Measurement of Aerosol Shape Factors

Abstract

The dynamic shape factor K and the coagulation shape factor f of two metal-oxide aerosols, platinum oxide and uranium dioxide, are determined by means of experiments. For this purpose, special measuring and evaluating methods are developed that are independent of the shape of the particles examined. The dynamic shape factor is determined separately for the different size fractions, whereas the coagulation shape factor is calculated by averaging the entire size range examined. The experiments show that the results of experiments with a given aerosol system cannot be automatically transferred to other aerosol systems. The shape of particles of a given size depends on the specific properties of the material and on the prevailing experimental conditions during aerosol generation. For both aerosol systems that are examined, the mean dynamic shape factor—averaged over the total size range examined—agrees roughly with the coagulation shape factor.