Methods for Describing Airborne Fractions of Free Fall Spills of Powders and Liquids.

摘要

The report describes methods for estimating the fractions of liquid and powder that produce aerosols in hypothetical spills. The characteristics of these aerosols are also described. The methods developed were based on previous data on the free fall spills in static air of aqueous solutions of uranyl nitrate, uranine, sucrose solutions and slurries, and titanium dioxide powders (Sutter et al. 1981, Ballinger and Hodgson 1986). After the liquid spill data were corrected for evaporation and settling, regression analysis of the data was produced correlating the fraction of a spill make airborne with dimensionless numbers containing the following parameters: spill height, liquid viscosity, liquid density, air density, and volume of liquid spilled. Statistical descriptions of the log normal distributions were provided for parameters of liquid aerosols. Powder aerosols formed as the powder fell. A dimensional analysis of the powder that dispersed while falling correlated well with the Galileo number, Ga, a dimensionless number containing the parameters mass of powder spilled, powder bulk density, air density, and air viscosity. A computer code was developed to predict the amount airborne at specified time steps after a powder spill.