ID#: 185
Abstract Title: Detonation Properties of a Model Condensed-Phase Explosive with a Pressure Sensative Rate Law
Session Title: Condensed Phase Explosions/Detonations
Session Date: 7/30/01
Session Start Time: 2:00 PM
Contributing Author: Aslam, T.D.
Organization: Los Alamos National Laboratory
Country: USA
Authors: Tariq D. Aslam
Short Abstract: During the course of modeling detonations in condensed-phase explosives, one typically resorts to empirical models for describing both the rate of chemical energy release and the equation of state of the explosive. The model examined here incorporates a pressure sensitive rate law, and an ideal equation of state, with \gamma=3, appropriate for a condensed-phase explosive. This particular model has been studied theoretically using a weakly-curved, quasi-steady asymptotic approach called detonation shock dynamics (DSD). The asymptotic theory yields an intrinsic propagation law for the detonation shock front. In particular, there will be a relation between the normal detonation shock speed, the acceleration of the normal detonation speed, the second derivative (along the shock) of the detonation speed and the curvature of the shock. One of the primary focuses of this paper will be to carry out direct numerical simulations (DNS) of the model and investigate the diameter effect in unconfined charges of explosives (planar geometry) for various charge diameters and pressure sensitivity parameters. To treat the resulting multi-material flow, an adaptive mesh refinement strategy is used in conjunction with the ghost fluid algorithm. Phenomenologically, we find that the low sensitive rate laws can support a steady traveling wave for arbitrary stick radii, while for more sensitive rate laws we find that there is a critical radius, below which a steady traveling solution doesn't exist. We find that the DSD theory is qualitatively accurate, and quantitatively accurate when the detonation is stable and not near failure.