A Statistical Hot Spot Reactive Flow Model for Shock Initiation and Detonation of Solid High Explosives

Phenomenological reactive flow models for the shock initiation and detonation of solid high explosives, such as the Ignition and Growth model and the Johnson-Tang-Forest (JTF) model have been very successful in reproducing most of the main features of these reactive flows. The reaction rate expressions in these models depend upon the average compressions and pressures attained in the reacting explosive mixture rather than the local “hot spot” temperatures, which are known to control the reaction rates in the preferentially heated regions of the explosive charge. Thus there are some situations, such as shock desensitization, that are not easily treated by these phenomenological models. Mesoscale modeling of the shock compression and temperature dependent chemical decomposition of individual explosive particles are currently yielding accurate predictions of hot spot formation mechanisms and the subsequent growth (or failure) of these hot spot reactions in the surrounding grains. For twoand three-dimensional simulations of realistic size explosive charges, a statistical hot spot model that averages over thousands of individual hot spot dimensions and temperatures and then allows the chemical reactions to grow (or fail to grow) due to thermal conduction is required. Some simple statistical hot spot models were developed several years ago in onedimensional hydrodynamic codes, but practical hot spot models in multidimensional codes are just beginning to appear.