Experimentation and direct numerical simulation of self-similar convergent detonation wave

Abstract

Abstract.The propagation of self similar convergent detonation wave in TATB-based explosive composition was studied both experimentally and numerically. The device constists in a 50 mm cylinder of TATB surrounded by an HMX tube. The detonation in HMX overdrives the detonation in TATB which adapts to the propagation velocity with a convergent front at centerline. We measured a curvature of κ = −21.2 m −1 for propagation velocity of 8750 m/s, which extends the knowledge of the (D n , κ) law. A wide ranged EOS/reaction rate model inspired from previous work of Wescott et al. was calibrated to reproduce both the run-to-detonation distance and the newly extended (D n , κ) law for the 1D sligthly curved detonation theory. 2D Direct Numerical Simulations (DNS) were made on fine resolved mesh grid for the experimental configuration and for various driver velocities. The simulation reproduces the experimental data both qualitatively (overall detonation structure) and quantitatively (κ = −25.4 m −1 ).

Theoretical study of the influence of the equation of state mixture properties on the velocitycurvature relationship for heterogeneous solid explosives

“…The rate law is then calibrated to match both the run to detonation distance and the experimental celerity-curvature curve. The coefficients are calibrated to reproduce a TATB based explosive composition [3,4].…”

“…In its simplest form in ref [3,4], the closure for the reactive equation of state used the hypothesis of ideal energy mixing, pressure equilibrium p=p S =p G and same volume v=v S =v G (for simplicity). In the following we will keep pressure equilibrium p=p S =p G and ideal mixture hypothesis and investigate several closures either based on physical assumptions: -thermal equilibrium T S = T G , -isentropic reactants dS S = 0, or idealized assumptions:…”