Bulletin of the American Physical Society
18th Biennial Intl. Conference of the APS Topical Group on Shock Compression of Condensed Matter held in conjunction with the 24th Biennial Intl. Conference of the Intl. Association for the Advancement of High Pressure Science and Technology (AIRAPT)
Volume 58, Number 7
Sunday–Friday, July 7–12, 2013; Seattle, Washington
Session J5: EM.2 Nonconventional Energetics: Blast Effects |
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Chair: John Reynolds, Lawrence Livermore National Laboratory Room: Cascade I |
Tuesday, July 9, 2013 11:00AM - 11:30AM |
J5.00001: Recent energetic materials research and capabilities at the centers Invited Speaker: Jon Maienschein |
Tuesday, July 9, 2013 11:30AM - 11:45AM |
J5.00002: High-Temperature and Pressure Aluminum Reactions in Carbon Dioxide Rich Post-Detonation Environments Bryce Tappan, Virginia Manner, Steven Pemberton, Mark Lieber, Carl Johnson, Eric Sanders Powdered aluminum is a common additive to energetic materials, but little is understood regarding its reaction rate at very high temperatures and pressures in specific oxidizing gases such as carbon dioxide. Aluminum reaction kinetics in carbon dioxide have been studied in various reaction conditions, but difficulties arise in the more specific study of Al oxidation at the high pressures and temperatures in detonation reactions. To study these reactions, small particle size Al or the inert surrogate, LiF, was added to the energetic material benzotrifuroxan (BTF). BTF is a hydrogen-free material that selectively forms CO2 as the major oxidizing species for post-detonation Al oxidation. High-fidelity PDV measurements were utilized for early wall velocity expansion measurements in 12.7 mm copper cylinders. The JWL equation of state was solved to determine temperature, pressure and energies at specific time periods. A genetic algorithm was used in conjunction with a numerical simulation hydrocode, ALE3D, which enables the elucidation of aluminum reaction extent. By comparison of the Al oxidation with LiF, data indicate that Al oxidation occurs on an extremely fast time scale, beginning and completing between 1 and 25 microseconds. Unconfined, 6.4 mm diameter rate-sticks were also utilized to determine the effect of Al compared to LiF on detonation velocity. [Preview Abstract] |
Tuesday, July 9, 2013 11:45AM - 12:00PM |
J5.00003: Measurements of Near-Field Blast Effects with Kinetic Plates Virginia Manner, Steven Pemberton, Geoffrey Brown, Stephanie Neuscamman, Bryce Tappan, Larry Hill, Daniel Preston, Lee Glascoe Few tests have been designed to measure the near-field blast impulse of ideal and non-ideal explosives, mostly because of the inherent experimental difficulties due to thermal effects on gauges and non-transparent fireballs. In order to measure blast impulse in the near field, a new test has been developed by firing spherical charges at 15.2 cm from steel plates and probing acceleration using laser velocimetry. Tests measure the velocity imparted to the steel plate in the 50 - 300 microsecond timeframe, and are compared with free-field over-pressure measurements at 1.52 meters and millisecond timescales using piezoelectric pencil gauges. Specifically, tests have been performed with C4 to probe the contributions of ideal explosives and charge size effects. Non-ideal aluminized explosive formulations have been studied to explore the role of aluminum in near-field blast effects and far-field pressure, and are compared with formulations using LiF as an inert surrogate replacement for Al. The results are compared with other near-field blast tests and cylinder tests, and the validity of this test is explored with modeling and basic theory. [Preview Abstract] |
Tuesday, July 9, 2013 12:00PM - 12:15PM |
J5.00004: Numerical Simulations of Near-Field Blast Effects using Kinetic Plates Stephanie Neuscamman, Virginia Manner, Geoffrey Brown, Lee Glascoe Numerical simulations using two hydrocodes were compared to near-field measurements of blast impulse associated with ideal and non-ideal explosives to gain insight into testing results and predict untested configurations. The recently developed kinetic plate test was designed to measure blast impulse in the near-field by firing spherical charges in close range from steel plates and probing plate acceleration using laser velocimetry. Plate velocities for ideal, non-ideal and aluminized explosives tests were modeled using a three dimensional hydrocode. The effects of inert additives in the explosive formulation were modeled using a 1-D hydrocode with multiphase flow capability using Lagrangian particles. The relative effect of particle impact on the plate compared to the blast wave impulse is determined and modeling is compared to free field pressure results. This work is performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. This is abstract LLNL-ABS-622152. [Preview Abstract] |
Tuesday, July 9, 2013 12:15PM - 12:30PM |
J5.00005: Effect of Aluminium Confinement on ANFO Detonation Mark Short, Scott Jackson, Charles Kiyanda, Mike Shinas, Steve Hare, Matt Briggs Detonations in confined non-ideal high explosives often have velocities below the confiner sound speed. The effect on detonation propagation of the resulting subsonic flow in the confiner (such as confiner stress waves traveling ahead of the main detonation front or upstream wall deflection into the HE) has yet to be fully understood. Previous work by Sharpe and Bdzil (J. Eng. Math, 2006) has shown that for subsonic confiner flow, there is no limiting thickness for which the detonation dynamics are uninfluenced by further increases in wall thickness. The critical parameters influencing detonation behavior are the wall thickness relative to the HE reaction zone size, and the difference in the detonation velocity and confiner sound speed. Additional possible outcomes of subsonic flow are that for increasing thickness, the confiner is increasingly deflected into the HE upstream of the detonation, and that for sufficiently thick confiners, the detonation speed could be driven up to the sound speed in the confiner. We report here on a further series of experiments in which a mixture of ammonium nitrate and fuel oil (ANFO) is detonated in aluminum confiners with varying HE charge diameter and confiner thickness, and compare the results with the outcomes suggested by Sharpe and Bdzil. [Preview Abstract] |
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