Simulation of Condensed‐Explosive Detonation Phenomena with Gases

Abstract

The detonation of a condensed explosive within a solid container and the detonation of a gaseous explosive within an inert‐gas boundary are found to be hydrodynamically similar situations. Experiments with hydrogen, methane, ethane, and propane‐oxygen mixtures confined by air or helium boundaries show that, as with condensed explosives, the properties of the boundary strongly influence the detonation characteristics of the explosive. Schlieren photographs of the interaction process between a gaseous detonation wave and an inert‐compressible‐gas boundary show that the detonation wave becomes curved, and in some cases is quenched, the quenching process being initiated at the compressible boundary. Either oblique or detached shocks are found to occur in the boundary. These observations parallel those made from experiments in which condensed explosives were confined by solid boundaries. With the use of an idealized‐flow model, the acoustic‐impedance ratio of the gaseous boundary to the explosive is determined to be the parameter which characterizes the confining ability of the boundary. Application of these results to condensed‐explosive detonations provides an understanding of some experimentally observed phenomena