Accession Number : AD0806642

Title :   A STUDY OF THE SETTLING OF CONCENTRATED AEROSOL CLOUDS.

Descriptive Note : Final rept. 15 Apr-31 Dec 65,

Corporate Author : BATTELLE MEMORIAL INST COLUMBUS OH COLUMBUS LABS

Personal Author(s) : Mitchell, R. I. ; Gieseke, J. A. ; Putnam, A. A. ; Pilcher, J. M. ; Schulz, E. J.

Report Date : DEC 1966

Pagination or Media Count : 97

Abstract : The objective of this research was to develop an understanding of the settling behavior of concentrated aerosol clouds (mass subsidence) and to determine the effect of mass subsidence on the history of aerosols. A thorough literature review of the subject was made, and a theoretical study was conducted to establish critical design considerations of the experimental equipment. Due to its ease of formation, cigarette smoke was used as the test aerosol and settling determinations were made both in cylindrical and rectangular settling chambers. For these studies the concentration of the smoke and the density of the gaseous medium were varied. The results of these studies showed that it was possible to obtain settling velocities several hundred times higher than that predicted by Stoke's law. During these studies both high-speed movies and still photographs were taken to document the types of aerosol breakup that were obtained. Because of the difficulty in reproducing experimental trials using a gaseous medium, it was decided to model the system with uniformly sized glass beads suspended in glycerine. Numerous studies were conducted in which the volume of the cloud and concentration of beads in the cloud were varied. The type of cloud breakup obtained with the liquid system was very similar to that obtained in the gaseous system. The settling velocity obtained with a high concentration of beads was approximately 30 times that of a single bead. (Author)

Descriptors :   (*AEROSOLS, ATMOSPHERIC PRECIPITATION), CONCENTRATION(CHEMISTRY), VELOCITY, DENSITY, SIMULATION, SMOKE, HIGH SPEED PHOTOGRAPHY, GLASS, SPHERES, GLYCEROLS.

Subject Categories : Meteorology
      Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE