Projectile Impact Ignition Characteristics of Propellants.

Abstract

Abstract : The results of an investigation of the projectile impact ignition characteristics of propellants are described. Impact tests were conducted on a single, double and triple base propellant, and a deflagratable composite explosive. The tests were conducted by firing different diameter, flat-nosed brass projectiles into small cylinders of the propellant at various velocities and observing the impact reaction by various sensors. The general behavior of the four materials to impact was the same. The critical impact velocity necessary to induce a sustained reaction in a propellant decreased with increasing projectile diameter. The nature of the reaction depended on the diameter. At small diameters, the induced reaction was always detonation; whereas at the largest diameter the reaction was deflagration, whose intensity increased with increasing impact velocity. A higher critical velocity then again resulted in detonation. A model based on the view that the ignition and reaction in an impacted (shocked) propellant are independent processes was postulated to explain the results. The critical velocity for inducing ignition was consistent with the critical energy concept.