Estimating Energy Release in Metallized Composite Explosives Using the Taylor Model

Abstract

The potential for reactive metal fuels to enhance the energetic output of high explosives has generated an enduring interest in the study of composite explosives. It has typically been demonstrated that added metal fuels can have little or even deleterious impact on the accelerating ability of composite military explosives relative to baseline performance. Often this has led to the assumption of limited reaction of the metal fuel over microsecond timescales. The widespread availability of Photonic Doppler Velocimetry has enabled time resolved measurement of accelerated confinement, ultimately demonstrating prompt reaction of metal fuels. Motivated by this observation, hydrocode modelling studies, and prior author's modifications of Taylor's tubular bomb model, we developed a differential equation form of Taylor's model in a manner where it is straightforward to add sources or phases. An afterburning version of the JWL equation of state was used to add energy to the gaseous products at a linear, time-dependent rate. The metal particles are assumed to remain in velocity equilibrium with the gaseous products and do not transfer heat or influence chemical composition. We focus exclusively on added aluminum as it remains the most ubiquitous choice of metal fuel. The model is initialized with a CJ state calculated from Cheetah 2.0 assuming the Al particles are inert in the detonation. JWL coefficients for the baseline explosive are also used. Qualitative agreement is observed between the model and previously published experiments.