Dark waves in liquid homogeneous explosives with unstable detonation front

Abstract

An explanation is given of the detailed mechanism of the divergent and convergent dark waves that originate at the charge boundary in detonating liquid homogeneous explosives with unstable detonation front. The mechanism involves the propagating failure wave that transmits the breakdown of the chemical reaction, and two different propagation modes for spreading the reinitiated detonation into the charge. Experiments with artificially induced divergent dark waves show that there are three different induction times for the reinitiating adiabatic thermal explosion. The size of a boundary irregularity in relation to the pertinent induction time is shown to be the controlling parameter that decides what kind of dark wave will result. The conditions for transition from convergent to divergent dark wave are given with reference to experiments that demonstrate the transition. The boundary-induced dark waves traverse the charge and become part of the general pattern of transverse reaction breakdown and reinitiating triple waves that are inherent in the normal process of propagation of a detonation with unstable front.