Equation of state and reaction rate for condensed-phase explosives

TLDR

The wide‑range equation of state is a nonideal model based on empirical fitting forms derived from thermodynamic principles that capture the essential physical features of detonation. The authors calibrate the PBX‑9502 equation of state and reaction rate by fitting products and reactants Hugoniot data, as well as detonation shock speed–curvature and wedge test data, to empirical forms. Simulations using the calibrated model predict particle‑velocity transients and steady detonation behavior that agree with gas‑gun and rate‑stick experiments.

Abstract

The wide-ranging equation of state is a nonideal equation of state based on empirical fitting forms argued from thermodynamic considerations that yield the proper physical features of detonation. The complete equation of state forms are presented and the equation of state and a reaction rate are calibrated for the condensed-phase explosive PBX-9502. Experimental overdriven Hugoniot data are used to calibrate the products equation of state off the principal isentrope passing through the Chapman-Jouguet state. Shock Hugoniot data are used to calibrate the reactants equation of state. The normal detonation shock speed-shock curvature data (Dn−κ) from rate-stick measurements and shock initiation data from wedge tests are used to calibrate the reaction rate. Simulations are carried out that predict detailed particle velocity transients that are measured experimentally with embedded electromagnetic gauge measurements from gas-gun experiments. Multidimensional simulations of steady detonation in a right circular cylinder rate stick are carried out and compared with experiment.