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 U3: EM.1 Energetic Materials Equation of State II |
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Chair: Seth Root, Sandia National Laboratories Room: Fifth Avenue |
Thursday, July 11, 2013 11:00AM - 11:15AM |
U3.00001: Plate impact experiments on the TATB based explosive PBX 9502 at pressures near the Chapman-Jouguet state R.L. Gustavsen, T.D. Aslam, B.D. Bartram, B.C. Hollowell We have completed a series of two-stage gas-gun driven plate-impact experiments on PBX 9502 (95 wt.\% tri-amino-trinitro-benzene, 5 wt.\% Kel-F800 plastic binder). The ultimate goal of these experiments is to provide, in the neighborhood of the Chapman-Jouguet state, overdriven product Hugoniot data that can be untangled from the transients leading up to a steady wave. Our approach is to do sets of experiments in which the thickness of the PBX 9502 is varied (6, 9, and 12 mm) while holding the flyer material (oxygen free high conductivity copper) and impact velocity constant. Sets of experiments have been conducted with flyer velocity 3.0 km/s ($\approx$ 34 GPa), 2.8 km/s ($\approx$ 31 GPa) and 2.6 km/s ($\approx$ 28 GPa). Wave profiles of the transmitted shock wave are measured at the interface of the back of the sample and a Lithium Fluoride (LiF) window. From each of these sets of experiments, a steady shock wave velocity can be extracted. Particle velocity and pressure are calculated by way of impedance matching. Finally, the wave profiles can be compared with reactive-burn -- equation-of-state models using direct numerical simulations. [Preview Abstract] |
Thursday, July 11, 2013 11:15AM - 11:30AM |
U3.00002: Equation of state of detonation products based on statistical mechanical theory Yanhong Zhao, Haifeng Liu, Gongmu Zhang, Haifeng Song The equation of state (EOS) of gaseous detonation products is calculated using Ross's modification of hard-sphere variation theory and the improved one-fluid van der Waals mixture model. The condensed phase of carbon is a mixture of graphite, diamond, graphite-like liquid and diamond-like liquid. For a mixed system of detonation products, the free energy minimization principle is used to calculate the equilibrium compositions of detonation products by solving chemical equilibrium equations. Meanwhile, a chemical equilibrium code is developed base on the theory proposed in this article, and then it is used in the three typical calculations as follow:(i) Calculation for detonation parameters of explosive, the calculated values of detonation velocity, the detonation pressure and the detonation temperature are in good agreement with experimental ones. (ii) Calculation for isentropic unloading line of RDX explosive, whose starting points is the CJ point. Comparison with the results of JWL EOS it is found that the calculated value of gamma is monotonically decreasing using the presented theory in this paper, while double peaks phenomenon appears using JWL EOS. [Preview Abstract] |
Thursday, July 11, 2013 11:30AM - 12:00PM |
U3.00003: Computations of fluid mixtures including solid carbon at chemical equilibrium Invited Speaker: Emeric Bourasseau One of the key points of the understanding of detonation phenomena is the determination of equation of state of the detonation products mixture. Concerning carbon rich explosives, detonation products mixtures are composed of solid carbon nano-clusters immersed in a high density fluid phase. The study of such systems where both chemical and phase equilibriums occur simultaneously represents an important challenge and molecular simulation methods appear to be one of the more promising way to obtain some answers. In this talk, the Reaction Ensemble Monte Carlo (RxMC) method will be presented. This method allows the system to reach the chemical equilibrium of a mixture driven by a set of linearly independent chemical equations. Applied to detonation product mixtures, it allows the calculation of the chemical composition of the mixture and its thermodynamic properties. Moreover, an original model has been proposed to take explicitly into account a solid carbon meso-particle in thermodynamic and chemical equilibrium with the fluid. Finally our simulations show that the intrinsic inhomogeneous nature of the system (i.e. the fact that the solid phase is immersed in the fluid phase) has an important impact on the thermodynamic properties, and as a consequence must be taken into account. [Preview Abstract] |
Thursday, July 11, 2013 12:00PM - 12:15PM |
U3.00004: Determination of sound velocities of ``overcompressed'' detonation in HMX-based explosive Alexey Kovalev, Mikhail Zhernokletov, Vladimir Bel'sky, Evgeny Bogdanov The authors present results of determination of sound velocities in explosion products (EP) of HMX-based explosive overcompressed up to the pressures of 50-85~GPa by overtaking unloading method. The radiowave and optical methods are used to record the time when front of overcompressed detonation wave in investigated sample of high explosive (HE) is overtaken by expansion wave, which propagates from the back surface of impactor with sound velocity. The data on sound velocities, which were independently obtained by two different methods, were in agreement. The methods with use of radiointerferometer and indicator liquid are rather effective for determination of sound velocities in overcompresed EP and for investigation of parameters in the Jouget point of various HEs, which are required for calibration of their equations of state (EOS). [Preview Abstract] |
Thursday, July 11, 2013 12:15PM - 12:30PM |
U3.00005: Improved Relationships for the Thermodynamic Properties of Carbon Phases at Detonation Conditions Leonard Stiel, Ernest Baker, Daniel Murphy In order to improve the procedures utilized in the Jaguar thermochemical program for carbon, volumetric and heat capacity relationships have been developed for graphite, diamond, and liquid carbon forms. Available experimental thermodynamic property and Hugoniot data have been analyzed to establish optimum equations of state for the carbon phases. The appropriate carbon form or multiple forms at equilibrium results from the minimization of the Gibbs free energy of the system. The resulting relationships are utilized to examine the phase behavior of carbon at elevated temperatures and pressures. The behavior of metastable carbon states is optimized by analyses of Hugoniot data for hydrocarbons, and C-J and cylinder velocities for a database of CHNO explosives. The accuracy of the resulting relationships is demonstrated by comparisons for several properties, including the Hugoniot behavior of oxygen-deficient explosives at overdriven conditions. [Preview Abstract] |
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