Experimental and theoretical progress on an All-Arrhenius model of solid explosive shock initiation
Phenomenological shock initiation models, such as Ignition and Growth (I and G) and Johnson-Tang-Forest (JTF), have been very successful in predicting the vast majority of reactive flow states produced during shock initiation and detonation of solid explosives. However, because their reaction rates are pressure and compression dependent and their equations of state are not complete enough to describe all of the available experimental data, these models can not be expected to describe all explosive initiation phenomena. For example, the effects of initial particle size distributions and initial temperature can not be modeled without defining a separate set of model coefficients for each condition. Therefore a new shock initiation model is being developed in the ALE3D and LS-DYNA2D/3D hydrodynamic codes, in which heat transfer and detailed chemical kinetic mechanisms are directly coupled into the hydrodynamic equations. This model creates ''hot spots'' by various postulated mechanisms (void collapse, friction, shear, etc.), determines whether these hot spots are large and hot enough to react and grow, and then calculates the spreading rates of the growing reaction sites. The reactions are propagated as they are in nature: by heat transfer using Arrhenius kinetics. The chemical decomposition mechanisms are based on thermal explosion experimental data. The most difficult problem encountered thus far involves modeling the physical mechanisms that produce the large increases in reactive surface area necessary to produce the rapid pressure buildups measured during transitions to detonation. Current research on reaction rates, equations of state, mixture rules, etc. are discussed. The experimental techniques and measurements required for model normalization are also discussed.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE Office of Defense Programs (DP) (US)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 12157
- Report Number(s):
- UCRL-JC-134603; DP0101011; DP0101011; TRN: AH200119%%356
- Resource Relation:
- Conference: International Shock Waves Workshop, College Park, MD (US), 07/06/1999--07/09/1999; Other Information: PBD: 1 Jun 1999
- Country of Publication:
- United States
- Language:
- English
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