Two-phase modeling of deflagration-to-detonation transition in granular materials: A critical examination of modeling issues
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
- Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)
- University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)
The two-phase mixture model developed by Baer and Nunziato (BN) to study the deflagration-to-detonation transition (DDT) in granular explosives is critically reviewed. The continuum-mixture theory foundation of the model is examined, with particular attention paid to the manner in which its constitutive functions are formulated. Connections between the mechanical and energetic phenomena occurring at the scales of the grains, and their manifestations on the continuum averaged scale, are explored. The nature and extent of approximations inherent in formulating the constitutive terms, and their domain of applicability, are clarified. Deficiencies and inconsistencies in the derivation are cited, and improvements suggested. It is emphasized that the entropy inequality constrains but does not uniquely determine the phase interaction terms. The resulting flexibility is exploited to suggest improved forms for the phase interactions. These improved forms better treat the energy associated with the dynamic compaction of the bed and the single-phase limits of the model. Companion papers of this study [Kapila {ital et al.}, Phys. Fluids {bold 9}, 3885 (1997); Kapila {ital et al.}, in preparation; Son {ital et al.}, in preparation] examine simpler, reduced models, in which the fine scales of velocity and pressure disequilibrium between the phases allow the corresponding relaxation zones to be treated as discontinuities that need not be resolved in a numerical computation. {copyright} {ital 1999 American Institute of Physics.}
- OSTI ID:
- 289209
- Journal Information:
- Physics of Fluids (1994), Vol. 11, Issue 2; Other Information: PBD: Feb 1999
- Country of Publication:
- United States
- Language:
- English
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