Explosibility of Explosive and Propellant Dusts

摘要

A specially design flow system was constructed to obtain more detailed data on the effect of particle size and concentration on the spark ignition of propellant and explosive dusts. With this apparatus the concentration can be controlled over a 1.5 m (5 ft), and streak photography can be employed to determine the velocity of flames and/or explosion waves. Thus information on both ignition and propagation can be obtained. The ignition characteristics of M1 propellant, RDX, HMX, and ball powder were determined. The concentration was varied from 0.15 to 1.5 g/liter, and the particle size was from 75 to 225 micrometers. Ignition with subsequent flame propagation required a concentration of at least 0.15 to 0.3 g/liter for all dusts tested. Values from previous studies conducted in a Hartmann apparatus ranged from 0.1222 g/liter to 0.5 g/liter for some of the same materials with similar particle sizes. Thus the lower limits of ignition are in good agreement; however, due to the relatively small size of the Hartmann apparatus, direct comparisons of ignition at upper limits are difficult.