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

 [1];  [1];  [2];  [1]
  1. University of Utah, Salt Lake City, UT 84112 USA
  2. Weber State University, Ogden, UT 84408 USA
Publication Date:
Sponsoring Org.:
OSTI Identifier:
Grant/Contract Number:
B524196; DEAC02-06CH11357; AC05-00OR22725; OCI1053575; TG-MCA08X004; TG-ASC150004
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Propellants, Explosives, Pyrotechnics
Additional Journal Information:
Journal Volume: 41; Journal Issue: 6; Related Information: CHORUS Timestamp: 2017-10-20 16:34:37; Journal ID: ISSN 0721-3115
Wiley Blackwell (John Wiley & Sons)
Country of Publication:

Citation Formats

Beckvermit, Jacqueline, Harman, Todd, Wight, Charles, and Berzins, Martin. Packing Configurations of PBX-9501 Cylinders to Reduce the Probability of a Deflagration to Detonation Transition (DDT). Germany: N. p., 2016. Web. doi:10.1002/prep.201500331.
Beckvermit, Jacqueline, Harman, Todd, Wight, Charles, & Berzins, Martin. Packing Configurations of PBX-9501 Cylinders to Reduce the Probability of a Deflagration to Detonation Transition (DDT). Germany. doi:10.1002/prep.201500331.
Beckvermit, Jacqueline, Harman, Todd, Wight, Charles, and Berzins, Martin. Thu . "Packing Configurations of PBX-9501 Cylinders to Reduce the Probability of a Deflagration to Detonation Transition (DDT)". Germany. doi:10.1002/prep.201500331.
title = {Packing Configurations of PBX-9501 Cylinders to Reduce the Probability of a Deflagration to Detonation Transition (DDT)},
author = {Beckvermit, Jacqueline and Harman, Todd and Wight, Charles and Berzins, Martin},
abstractNote = {},
doi = {10.1002/prep.201500331},
journal = {Propellants, Explosives, Pyrotechnics},
number = 6,
volume = 41,
place = {Germany},
year = {Thu Aug 04 00:00:00 EDT 2016},
month = {Thu Aug 04 00:00:00 EDT 2016}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1002/prep.201500331

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  • In this paper, the authors present results of an experimental and theoretical study of the combustion processes associated with deflagration-to-detonation transition in the granular explosive, CP. Image-enhanced, high-speed streak photography recorded the various stages of flame spread within heavily confined charges as viewed through a Lexan window in a thick-wall, stainless steel tube. To characterize the phenomena, we applied a multiphase reactive flow model based on the theory of mixtures. This nonequilibrium model treated each phase as fully compressible and incorporated a compaction model for the granular reactant. Formulation of the constitutive models included a pressure-dependent burn rate and experimentallymore » determined porous bed permeablility. Predictions of this model were in good agreement with experimental observations.« less
  • The delayed detonation model describes the observational properties of the majority of Type Ia supernovae very well. Using numerical data from a three-dimensional deflagration model for Type Ia supernovae, the intermittency of the turbulent velocity field and its implications on the probability of a deflagration-to-detonation (DDT) transition are investigated. From structure functions of the turbulent velocity fluctuations, we determine intermittency parameters based on the log-normal and the log-Poisson models. The bulk of turbulence in the ash regions appears to be less intermittent than predicted by the standard log-normal model and the She-Leveque model. On the other hand, the analysis ofmore » the turbulent velocity fluctuations in the vicinity of the flame front by Roepke suggests a much higher probability of large velocity fluctuations on the grid scale in comparison to the log-normal intermittency model. Following Pan et al., we computed probability density functions for a DDT for the different distributions. The determination of the total number of regions at the flame surface, in which DDTs can be triggered, enables us to estimate the total number of events. Assuming that a DDT can occur in the stirred flame regime, as proposed by Woosley et al., the log-normal model would imply a delayed detonation between 0.7 and 0.8 s after the beginning of the deflagration phase for the multi-spot ignition scenario used in the simulation. However, the probability drops to virtually zero if a DDT is further constrained by the requirement that the turbulent velocity fluctuations reach about 500 km s{sup -1}. Under this condition, delayed detonations are only possible if the distribution of the velocity fluctuations is not log-normal. From our calculations follows that the distribution obtained by Roepke allow for multiple DDTs around 0.8 s after ignition at a transition density close to 1 x 10{sup 7} g cm{sup -3}.« less
  • The research presented examines DDT of cylinders of PBX 9501 damaged above 180 C in heavy confinement for 0-3 hours and end-ignited or ramped until self-ignition (cookoff) occurred. Progression of luminous reaction was observed by streak photography through a glass-filled slit running the length of the cylinder. Post-mortem analysis of the steel DDT tubes was also done for correlation with the optical records. Results indicate that repeatable, Type I DDT was observed to occur in hot, thermally damaged PBX 9501 with low levels of porosity. It was demonstrated that multiple parameters affect DDT behavior, most likely in a coupled fashion.more » These parameters are porosity, ignition temperature and thermal soak duration. Conditions leading up to cookoff were shown to sensitize the HE to DDT by increasing likelihood and decreasing run length. Over the range of porosities (0-37%) and ignition temperatures (180-235 C), run lengths and detonation velocities varied, respectively, from approximately 22-109 mm and 6.0-8.3 mm {micro}s{sup -1}. This work fills a valuable and realistic space in the understanding of high explosive violent reaction, including DDT, in abnormal thermal environments.« less
  • In thermal explosions of the nitramine octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)-based explosives LX-10 and PBX-9501, the pre-ignition spatial and temporal heating profile defines the ignition location. The ignition location then determines the extent of inertial confinement and the violence of the resulting deflagration. In this work, we present results of experiments in which ∼23 g cylinders of LX-10 and PBX 9501 in thin-walled aluminum confinement vessels were subjected to identical heating profiles but which presented starkly different energy release signatures. Post-explosion LX-10 containment vessels were completely fragmented, while the PBX 9501 vessels were merely ruptured. Flash x-ray radiography images show that the initiation locationmore » for the LX-10 is a few mm farther from the end caps of the vessel relative to the initiation location of PBX 9501. This difference increases deflagration confinement for LX-10 at the time of ignition and extends the pressurization time during which the deflagration front propagates in the explosive. The variation in the initiation location, in turn, is determined by the thermal boundary conditions, which differ for these two explosives because of the larger coefficient of thermal expansion and greater thermal stability of the Viton binder in LX-10 relative to the estane and bis(2,2-dinitropropyl) acetal/formal binder of the PBX 9501. The thermal profile and initiation location were modeled for LX-10 using the hydrodynamics and structures code ALE3D; results indicate temperatures in the vicinity of the ignition location in excess of 274 °C near the time of ignition. The conductive burn rates for these two explosives, as determined by flash x-ray radiography, are comparable in the range 0.1–0.2 mm/μs, somewhat faster than rates observed by strand burner experiments for explosives in the temperature range 150–180 °C and pressures up to 100 MPa. The thinnest-wall aluminum containment vessels presented here rupture at lower pressures, in the range 10 MPa, suggesting that moderately higher temperatures and pressures are present near the deflagration front. For these explosives, however the most important property for determining deflagration violence is the degree of inertial confinement.« less
  • Sound speeds, at pressure, and the overdriven Hugoniot were measured for the plastic-bonded explosive PBX-9501. The two curves intersect at the Chapman{endash}Jouguet (CJ) state because of the sonic condition {ital D}={ital c}+{ital u}. This permitted a novel determination of the {open_quote}{open_quote}thermodynamic{close_quote}{close_quote} CJ pressure. A value of 34.8{plus_minus}0.3 GPa was obtained. The data permit a direct experimental determination of the isentropic gamma, {gamma}{sub {ital S}}={minus}({partial_derivative}ln{ital P}/{partial_derivative}ln{ital V}){sub {ital S}}, and the Gr{umlt u}neisen parameter, {gamma}={ital V}({partial_derivative}{ital P}/{partial_derivative}{ital E}){sub {ital V}}, in the overdriven pressure range. {copyright} {ital 1996 American Institute of Physics.}