Detonation Characteristics of Some Dusts and Liquid-Dust Suspensions.

摘要

The detonation characteristics of high explosive dusts dispersed in air were studied in a special 'shock tube type' facility wherein the dust was transported through the tube by a gas flow. Detonation of high pressure gases in the driver served to transmit a strong blast wave into the dust mixture. The resultant wave was monitored by pressure switches, pressure transducers, a photodiode, and streak photography. RDX dust in air could not be detonated. However, detonation was realized with 150-micrometre diameter particles in oxygen-enriched air. The small RDX particles (10 micrometre) could not be detonated, even with oxygen enrichment. The conclusion drawn was that the inertia of the large particles led to a large relative velocity between the particles and gas behind the shock wave with the attendant high stagnation temperature and rapid heating to ignition. Other experiments were conducted wherein excess oxygen was supplied by the addition of ammonium perchlorate dust, AP, to the RDX. The AP did increase the sensitivity and some detonation results are presented. Experiments were conducted on the shock wave ignition characteristics of liquid fuel drops with entrained small dust particles. The liquid fuel used was decane and the dusts included RDX, AP and inert aluminum oxide. In general, these dusts served to decrease the ignition time delay and hence to increase the detonability. A theoretical model was developed for the ignition time delay of dust particles behind a shock wave and gave good agreement with experiment results. An approximate model for the combustion rate of dust predicted the propagation rate and structure of a steady state dust detonation.