Measuring detonation wave profiles in plastic-bonded explosives using PDV

To obtain reaction zone parameters for several high explosives, experimental measurements of the detonation wave profiles in HMX-, RDX- and PETN-based explosives were performed using photon Doppler velocimetry (PDV). Planar detonations were produced by impacting the explosive with a sapphire flyer in a gas gun. Particle velocity wave profiles were measured at the explosive/window interface. LiF windows with very thin vapor-deposited aluminum mirrors were used for experiments. All measurements show a distinct end to the reaction zone, indicating a Chapman-Jouguet (CJ) point. For HMX-based explosives, the presented measurements show that the fast reaction time is approximately 10±2 ns, whereas for RDX- and PETN-based explosives, the values are 14±3 ns and 7±2 ns, respectively. The reaction times or reaction zone lengths obtained in the present study are smaller than previously reported data but much closer to the estimated values in theory. Additionally, the velocity at the Von Neumann (VN) spike was analyzed using the “beat cycles” method, and the pressure at the VN spike was obtained.