Properties of explosively driven aluminum particle fields and their inhalation hazards.

摘要

A high speed framing camera (HSFC) and a particle image velocimetry (PIV) instrument were used to determine the properties of explosively driven particle fields in microsecond and millisecond intervals. Two-inch long right circular cylindrical charges with half-inch diameter cores made of organic explosive were used as the driving explosive. The core was surrounded by a particle bed of aluminum or tungsten powder of a specific particle size distribution. Position data from the leading edge of the particle fronts for each charge were recorded with the framing camera at early time, first 125 mus, and with a PIV instrument at later time (5.7 ms) to determine the mean particle velocities. In addition, using a PIV image, a velocity gradient along the length of the particle field was established by using the mean particle velocity value determined from three separate horizontal bands that transverse the particle field. The results showed lower velocity particles at the beginning of the particle field closest to the source and higher velocity particles at the leading front portion of the field. Differences in particle dispersal, luminescence, and agglomeration were seen when changes in the initial particle size and material type were made. The aluminum powders showed extensive luminescence with agglomeration, forming large particle structures while a tungsten powder showed little luminescence, agglomeration and no particle structures. Combining velocity data from the HSFC and PIV, the average drag coefficient for each powder type was determined. The particle field velocities and drag coefficients at one meter showed good agreement with the numerical data produced from a computational fluid dynamics code.;The dissolution rate of aluminum powder in serum ultrafiltrate stimulant solution was conducted. A match to the International Commission on Radiological Protection, ICRP 66 lung model default value for the overall instantaneous clearance rate was determined. Using a ratio of volume moments derived from the sample powder system, a correction to the experimental dissolution rate constant was made to fit a mono distributed powder system that will allow the constant to be applied to other powder systems with different particle size distributions.