Bulletin of the American Physical Society
20th Biennial Conference of the APS Topical Group on Shock Compression of Condensed Matter
Volume 62, Number 9
Sunday–Friday, July 9–14, 2017; St. Louis, Missouri
Session K3: Energetic and Reactive Materials: Nitromethane |
Hide Abstracts |
Chair: Dana Dattelbaum, Los Alamos National Laboratory Room: Grand Ballroom FG |
Tuesday, July 11, 2017 2:15PM - 2:30PM |
K3.00001: Studies in shocked nitromethane through High dynamic range spectroscopy Mithun Bhowmick, Erin Nissen, Sergey Matveev, Dana Dlott In this talk we describe a tabletop apparatus that can reproducibly drive shocks through tiny cells containing liquid arranged in an array for high-throughput shock compression studies. This talk will focus on nitromethane, a liquid reactive to shocks and capable of detonation. In our studies, a laser-driven ?yer plate was used to shock nitromethane, and a spectrometer with high dynamic range was employed to measure emission spectra from nanosecond to millisecond time scales. Typically, 50 single-shock experiments were performed per day with precisely controllable shock speeds below, above, or equal to the detonation shock speed. The emission spectra provide temperature histories using the grey body approximation. The ability to conveniently shock nitromethane on a benchtop was used with isotopically substituted and amine-sensitized nitromethane and in future will be combined with other spectroscopies such as infrared absorption. [Preview Abstract] |
Tuesday, July 11, 2017 2:30PM - 2:45PM |
K3.00002: Molecular Dynamics Simulations of Shear Induced Transformations in Nitromethane James Larentzos, Brad Steele Recent experiments demonstrate that NM undergoes explosive chemical initiation under compressive shear stress. The atomistic dynamics of the shear response of single-crystalline and bi-crystalline nitromethane (NM) are simulated using molecular dynamics simulations under high pressure conditions to aid in interpreting these experiments. The atomic interactions are described using a recently re-optimized ReaxFF-lg potential trained specifically for NM under pressure. The simulations demonstrate that the NM crystal transforms into a disordered state upon sufficient application of shear stress; its maximum value, shear angle, and atomic-scale dynamics being highly dependent on crystallographic orientation of the applied shear. Shear simulations in bi-crystalline NM show more complex behavior resulting in the appearance of the disordered state at the grain boundary. [Preview Abstract] |
Tuesday, July 11, 2017 2:45PM - 3:00PM |
K3.00003: Dynamics of an Overdriven Nitromethane Initiation System E. H. H\'{a}roz, P. J. Rae, C. L. Armstrong, E. V. Baca, C. Campbell, J. A. Gunderson, M. Holmes, I. Lopez-Pulliam, L. D. Vaughan, P. M. Dickson For upcoming large-scale HE experiments, an initiation system is needed to ensure uniform and simultaneous burn. To that end, we developed an initiation system based on nitromethane. Initial, small-scale tests characterized the response of the nitromethane in the proposed cylindrical initiator geometry, indicating robust detonation under a variety of conditions such as a plane wave lenses \& cylinders of PBX 9501 into a flyer plate or direct-drive. Detonation velocity, as measured by piezoelectric pin time-of-arrival measurements along the length and at bottom of vessel, shows an overdriven response. All cases show a detonation velocity faster than the literature value of 7.3 km s$^{-1}$ for nitromethane, with the fastest velocity occurring for the 8-detonator, 8" cylinder case with a velocity = 7.7 km s$^{-1}$. Streak camera imaging characterized the curvature of the shock front as it arrived at the bottom of the vessel via spark gap. A final test of the initiator system looked at the expansion of the initiator vessel walls via PDV, showing velocities up to 3.5 km s$^{-1}$. Finally, our initiator was placed inside a secondary vessel containing 1000 lbs of nitromethane. High-speed photography \& pin data indicate complete symmetrical burn of the secondary nitromethane. [Preview Abstract] |
Tuesday, July 11, 2017 3:00PM - 3:15PM |
K3.00004: Non-classical detonation regimes of the mixtures of tetranitromethane/methanol and tetranitromethane/nitrobenzene. Valentina Mochalova, Alexander Utkin The experimental study of the liquid explosive tetranitromethane and its mixtures with not detonating liquids (methanol and nitrobenzene) is presented in this work. By the using of a laser interferometer VISAR the stability of detonation waves in that mixtures, depending on the diluent concentration, was investigated. It is shown that the detonation front of these mixtures is stable up to 40{\%} of diluent. Also the dependence of the detonation velocity of tetranitromethane/diluent on the diluent concentration and the limit concentration of the diluent, above which the detonation of the mixture was impossible, were found for each mixture. The compounds of the mixtures, in the reaction zone of which the distribution of parameters didn't correspond to the classical detonation theory, were found. An increase of the pressure and particle velocity behind a shock jump in the mixtures of tetranitromethane/methanol and tetranitromethane/nitrobenzene and the possibility of the existence of a steady-state detonation wave without a Von Neumann spike are interpreted within the framework of models that take into account the possibility of chemical reactions directly in the shock wave front. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700