Three-Dimensional Unsteady Reactive Two-Phase Flow Analysis to Predict Detonation Transition in Fragmented High Explosives/Warheads

摘要

Prior to fuse initiation, metal containment wall failure and fragmentation of the high explosive can result from the impact forces between the warhead and the hardened target. The detonation that is expected to occur under totally confined conditions may be reduced to an unsteady, rapid deflagration with much less damage to the target. The principal work presented in the report is the development of a three-dimensional unsteady flow model which can be used to predict whether detonation will occur after the impact of a ruptured warhead filled with fragmented high explosive. The delay of detonation transition can be quite significant if there is sufficient mass loss through container walls. This is clearly demonstrated here, where significant detonation delays could be predicted when using even a quasi, one-dimensional assumption. This report includes significant new findings and is the culmination of more than two years of effort to solve the two- and three-dimensional flow in a reactive gas/solid mixture. The results demonstrate that it may be possible to predict whether a warhead with case failure (and filled with fragmented high explosive) will produce a low order detonation which is weaker than one required to damage structures. A major portion of the report deals with the numerical methods required in order to carry out such solutions. Results include not only pressure histories but flow velocities, reaction from loci, and temperature distributions.