Numerical study on hypervelocity acceleration of flyer plates by overdriven detonation of high explosive

In most applications of explosives to flyer acceleration, the detonation of explosives is usually regarded as a steadily progressing wave phenomenon in which the pressure of the detonation products immediately behind the wave front is characterized by the so-called Chapman-Jouguet (C-J) pressure value. This type of detonation is therefore routinely referred to as the C-J detonation behavior and the detonation products start to expand from this C-J state to accelerate the flyer plate to a high velocity status. Overdriven detonation, however, is a detonation process that can provide a higher or much higher pressure than does the C-J detonation. Taking use of the detonation products from the overdriven detonation to push the plate may lead the plate to reach a hypervelocity status not achievable by means of the usual explosive acceleration techniques. This paper presents a numerical study on two acceleration systems for hypervelocity acceleration of plates by the application of overdriven detonation of explosives. The first acceleration system is the so-called planar acceleration system, which some researchers also call as the multi-stage launcher system. The other acceleration system is the improved technique that is named as the converging tunnel acceleration system. The numerical method used for the study mainly follows the formulation of HEMP computer code. Through numerical study, it is found that both systems can give an obvious improvement on the ability to hypervelocity acceleration of plates. Moreover, the comparison of two acceleration systems shows that the converging tunnel system has more superiority over the planar acceleration system for hypervelocity acceleration of plates.