The channel effect: Coupling of the detonation and the precursor shock wave by precompression of the explosive

摘要

The high-explosive channel effect is investigated to study the coupling dynamics of the precursor shock wave with the detonation. This is achieved experimentally by using porous pentaerythritol tetranitrate (PETN) powder in square channels. It is found that the precursor shock wave causes the detonation to accelerate to approximately 1.5 times the detonation velocity of the porous PETN. This phenomenon is found to be almost independent of the fill gas and the initial pressure in the channel. It is found that the precursor shock wave is insufficiently strong to initiate the PETN layer before the arrival of the main detonation front, and that the mechanism responsible for the observed acceleration is precompression of the explosive layer by the precursor shock wave. This mechanism is modeled analytically by generalizing an existing model for the precursor shock wave dynamics with boundary layers. The results agree well qualitatively and relatively well quantitatively considering the assumptions that are made. (C) 2004 American Institute of Physics.