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Title: Multiphase Equations for Modeling DDT in Damaged, Condensed-Phase Explosives

Abstract

No abstract provided.

Authors:
 [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1352438
Report Number(s):
LA-UR-17-23200
DOE Contract Number:
AC52-06NA25396
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE; Deflagration-to-Detonation Transition (DDT), Multiphase Modeling

Citation Formats

Bdzil, John Bohdan. Multiphase Equations for Modeling DDT in Damaged, Condensed-Phase Explosives. United States: N. p., 2017. Web. doi:10.2172/1352438.
Bdzil, John Bohdan. Multiphase Equations for Modeling DDT in Damaged, Condensed-Phase Explosives. United States. doi:10.2172/1352438.
Bdzil, John Bohdan. Wed . "Multiphase Equations for Modeling DDT in Damaged, Condensed-Phase Explosives". United States. doi:10.2172/1352438. https://www.osti.gov/servlets/purl/1352438.
@article{osti_1352438,
title = {Multiphase Equations for Modeling DDT in Damaged, Condensed-Phase Explosives},
author = {Bdzil, John Bohdan},
abstractNote = {No abstract provided.},
doi = {10.2172/1352438},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Apr 19 00:00:00 EDT 2017},
month = {Wed Apr 19 00:00:00 EDT 2017}
}

Technical Report:

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  • The overarching goal of this project was to develop a new continuum theory of multiphase flow in porous media. The theory follows a phase-field modeling approach, and therefore has a sound thermodynamical basis. It is a phenomenological theory in the sense that its formulation is driven by macroscopic phenomena, such as viscous instabilities during multifluid displacement. The research agenda was organized around a set of hypothesis on hitherto unexplained behavior of multiphase flow. All these hypothesis are nontrivial, and testable. Indeed, a central aspect of the project was testing each hypothesis by means of carefully-designed laboratory experiments, therefore probing themore » validity of the proposed theory. The proposed research places an emphasis on the fundamentals of flow physics, but is motivated by important energy-driven applications in earth sciences, as well as microfluidic technology.« less
  • In this report, we develop a two-phase mixture theory to describe the deflagration-to-detonation transition (DDT) in porous granular explosives. The theory is based on the continuum theory of mixtures and is able to account for both the compressibility of each phase and the compaction of the granular bed. By requiring the model to satisfy the Second Law of Thermodynamics, specific expressions for the exchange of mass, momentum and energy are proposed which are consistent with previously published empirical models. The model is then applied to the problem of DDT in a pressed column of HMX. Numerical results, using the methodmore » of lines, are obtained for a representative case of a 5 cm long bed and a grain size of 200 ..mu..m. The results are found to predict the transition to detonation in run distances commensurate with experimental observations. Additional calculations have been carried out to demonstrate the effect of particle size, porosity, gas product equation of state, drag correlation, compaction viscosity and burn rate on the run distance to detonation.« less
  • To model the shock-induced behavior of porous or damaged energetic materials, a nonequilibrium mixture theory has been developed and incorporated into the shock physics code, CTH. The foundation for this multiphase model is based on a continuum mixture formulation given by Baer and Nunziato. This multiphase mixture model provides a thermodynamic and mathematically-consistent description of the self-accelerated combustion processes associated with deflagration-to-detonation and delayed detonation behavior which are key modeling issues in safety assessment of energetic systems. An operator-splitting method is used in the implementation of this model, whereby phase diffusion effects are incorporated using a high resolution transport method.more » Internal state variables, forming the basis for phase interaction quantities, are resolved during the Lagrangian step requiring the use of a stiff matrix-free solver. Benchmark calculations are presented which simulate low-velocity piston impact on a propellant porous bed and experimentally-measured wave features are well replicated with this model. This mixture model introduces micromechanical models for the initiation and growth of reactive multicomponent flow that are key features to describe shock initiation and self-accelerated deflagration-to-detonation combustion behavior. To complement one-dimensional simulation, two-dimensional numerical calculations are presented which indicate wave curvature effects due to the loss of wall confinement. This study is pertinent for safety analysis of weapon systems.« less