PENETRATION OF POLYDISPERSE AEROSOLS THROUGH SCREEN DIFFUSION BATTERY

ABSTRACT

As an alternative data reduction scheme for diffusion battery measurements, penetration of polydisperse aerosol particles in a screen type diffusion battery has been calculated employing Brownian diffusion and interception as the applicable deposition mechanisms. The influences of the mean particle size and the geometric standard deviation of the aerosol on penetrations of the total particle number, radius, surface area, and the total particle volume have been examined. It is quantitatively shown that depending upon the type of aerosol instrument in use as a particle counting means and depending upon the size distribution of the measured aerosols, penetration characteristics can become markedly different. For a highly dispersed aerosol having a small mean particle size, the total radius, the surface area and the total volume of aerosol particles are shown to penetrate a diffusion battery more slowly in that order than the total number of particles. However, when the mean size of the aerosol increases, such a monotomic increase in penetration becomes no longer valid due to increasing importance of the interceptional deposition. Experimental measurements have been performed to demonstrate applications of the calculated results.