Multiscale modeling of high explosives for transportation accidents

Packing Configurations of PBX‐9501 Cylinders to Reduce the Probability of a Deflagration to Detonation Transition (DDT)

“…gaseousp roducts at multiple initial temperatures andp ressures [17,18,19,20].T he DDT modelu tilizes am odified Ward, Son, and Brewster (WSB) burn model [18,20,21] to evaluate the mass conversion rate, the ViscoSCRAM constitutive model [22] to model the damage in the solid, and the JWL ++ simple reactive flow model [23] to describe detonation.T he commonly used JWL equation of state [ 23,24] was used for the solid explosivea nd the product gases. Detonation occurs in Uintah's DDT model whent he localized pressure is greater than the pressure threshold, 5.3 GPa [17,18].F urther details on the model can be found in references [ 17,18,19,20,25].T he Uintah framework has al ong history of high performance computing and has shown goods trong and weak scaling characteristics up to 512 Kc ores on DOE's Mira [26,27,28].U intah's strong scalability enabled us to run large 2D and full 3D simulations at high grid resolutions (2 mm). The reactionm odel has been validated at many resolutions including 2mm [ 19,29].…”

“…Detonation occurs in Uintah's DDT model whent he localized pressure is greater than the pressure threshold, 5.3 GPa [17,18].F urther details on the model can be found in references [ 17,18,19,20,25].T he Uintah framework has al ong history of high performance computing and has shown goods trong and weak scaling characteristics up to 512 Kc ores on DOE's Mira [26,27,28].U intah's strong scalability enabled us to run large 2D and full 3D simulations at high grid resolutions (2 mm). The reactionm odel has been validated at many resolutions including 2mm [ 19,29]. Using this advanced computational tool it was possible to predict if at hermally ignited arrayo fe xplosives wouldu ndergo aD DT event.…”

Modeling Deflagration in Energetic Materials using the Uintah Computational Framework

“…By increasing the grid resolution from 0.25mm to 2mm large 3D simulations can be run using 512 times less computing power with only a 8% error associated with the time to detonation. Extensive research has been done on the effects of increasing the resolution on the burn rate and the detonation propagation [17]. We have determined that the rate of reaction for conductive [17] and convective deflagration have no dependence on the resolution and the denotation velocity is not affected by the increase of resolution until cells are 8mm or larger [17].…”

“…Our model for deflagrating PBX-9501 has been validated against experimental data for multiple pressures, initial temperatures and grid resolutions for conductive deflagration [18,17]. An abundance of research has been directed at understanding convective deflagration [14,5,7], but there are still many unknowns and no empirical correlations similar to Equations 1-5 and 9 to evaluate the mass burn rate and propagation velocity.…”

“…By evaluating the burn front area of convective deflagration with respect to a reference resolution the grid dependence was eliminated. The reference resolution of 2mm was chosen for our simulations because the flame propagation and conductive burn rates for this resolution lie within the experimental data and the resolution is large enough to run petascale simulations without loss of fidelity [17]. Until further experimental research is done to fully understand the mass burn rate with convective deflagration this approach, to the best of our knowledge, accurately represents convective deflagration and decreases the non-linearity in the simulations.…”