Optimization of Wall Velocity Measurements Using Photonic Doppler Velocimetry (PDV)

The paper describes the measurement of cylindrical charge wall velocity profiles at various angles to the surface normal. The wall velocities were measured using simple zero generation photonic Doppler velocimetry (PDV). The detonation velocity was measured simultaneously using fiber optic probes coupled with a digital chronometer. The PDV probe angles were set in the range of -2° to 17° to the surface normal. Powdered pentaerythritol tetranitrate (PETN) and the PETN-based plastic-bonded explosive Semtex 1A were selected as the explosive materials in order to ensure reliable detonation under the measurement conditions. The explosive charges were confined in thin-walled aluminum tubes with an internal diameter of 16 mm and wall thickness of 2 mm. The results can be useful for the characterization of charge expansion phenomena and also for the optimization of cylinder test measurements using PDV. Gurney constants were determined for both explosives.