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 L7: CM.1 Equation of State: Fluids |
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Chair: Gabriel Gwanmesi, Delaware State University Room: Grand Crescent |
Tuesday, July 9, 2013 3:30PM - 3:45PM |
L7.00001: Experimental Measurement of Speeds of Sound in Liquid Carbon Monoxide and Development of High-Pressure, High-Temperature Equations of State Joseph Zaug, Jeffrey Carter, Sorin Bastea, Michael Armstrong, Fried Laurence We report the adiabatic sound speeds for supercritical fluid carbon monoxide along two isotherms, from 0.17 to 2.13 GPa at 297 K and from 0.31 to 3.2 GPa at 600 K. The carbon monoxide was confined in a resistively heated diamond-anvil cell and the sound speed measurements were conducted in situ using a recently reported variant of the photoacoustic light scattering effect. The measured sound speeds were then used to parameterize a single site dipolar exponential-6 intermolecular potential for carbon monoxide. PT thermodynamic states, sound speeds, and shock Hugoniots were calculated using the newly parameterized intermolecular potential and compared to previously reported experimental results. Additionally, we generated an analytical equation of state for carbon monoxide by fitting to a grid of calculated PT states over a range of 0.1-10 GPa and 150-2000 K. A 2 percent mean variation was found between computed high-pressure solid-phase densities and measured data -a surprising result for a spherical interaction potential. We further computed a rotationally dependent fluid to beta-solid phase boundary; results signal the relative magnitude of short-range rotational disorder under conditions that span existing phase boundary measurements. [Preview Abstract] |
Tuesday, July 9, 2013 3:45PM - 4:00PM |
L7.00002: Shock Compression of Cryogenic Noble Gas Mixtures: Xenon -- Krypton Seth Root, Rudolph Magyar, Raymond Lemke, Thomas Mattsson In past work, we have examined the multi-Mbar response of cryogenically cooled liquid xenon and liquid krypton measuring their Hugoniots to 8 Mbar. These results were utilized in the development of new EOS models for Xe and Kr to use in high energy density physics applications. The previous work demonstrated the usefulness of integrating high accuracy shock compression experiments with DFT to generate the basis for equation of state (EOS) models. In many physics applications, such as Z-pinch experiments, gas mixtures are used instead. However, we do not have reliable experimental data on these mixtures to provide informed decisions about the EOS models or mixture rules. To improve our understanding of mixtures at extreme conditions, we performed dynamic compression experiments using Sandia's Z -- facility on a 70/30 molar ratio Kr/Xe cryogenically cooled liquid mixture. We measured the Hugoniot state and reshock state of the liquid mixture to several Mbar. The experimental data validated the DFT simulations for identical molar ratio mixtures. The combined experimental and DFT results are used to assess the EOS models and test the mixture rules. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Securities Administration under Contract No. DE-AC04-94AL85000. [Preview Abstract] |
Tuesday, July 9, 2013 4:00PM - 4:15PM |
L7.00003: Temperature Measurements in Shocked Liquid Benzene and an Improved Benzene EOS David Lacina, Y.M. Gupta Time-resolved Raman spectroscopy measurements were used to determine temperatures in multiply-shocked liquid benzene to peak pressures of $\sim$19GPa. Experimentally determined temperatures were obtained using the ratio of anti-Stokes to Stokes scattering intensities for the 992cm$^{-1}$ vibrational mode. Our experimental results demonstrate that the calculated temperatures obtained using the current benzene equation of state (EOS) [S. Root, Ph.D. Thesis, WSU], though reasonable, are consistently lower than the measurements. To improve calculated temperatures, key thermodynamic parameters (e.g. the specific heat) in the current benzene EOS were varied to examine and understand the sensitivity of temperatures to those parameters. Specific heat variations, as expected, resulted in the largest change in the calculated temperatures. Building on the sensitivity studies, the benzene EOS was refined to produce a good agreement between the calculated temperatures and the measured temperatures in multiply-shocked benzene. The improved EOS resulted in a higher decomposition temperature for singly shocked liquid benzene. [Preview Abstract] |
Tuesday, July 9, 2013 4:15PM - 4:30PM |
L7.00004: Shock Hugoniot Equations of State for Binary Ideal (Toluene/Fluorobenzene) and Non-Ideal (Ethanol/water) Liquid Mixtures Peter Schulze, Nhan Dang, Cynthia Bolme, Kathryn Brown, Shawn McGrane, David Moore Laser shock Hugoniot data were obtained using ultrafast dynamic ellipsometry (UDE) for both non-ideal (ethanol/water solutions with mole percent $\chi _{ethanol} \quad =$ 0{\%}, 3.4{\%}, 7.5{\%}, 11{\%}, 18{\%}, 33{\%}, 56{\%}, 100{\%}) and ideal liquid mixtures (toluene/fluorobenzene solutions with mole percent $\chi_{toluene} \quad =$ 0{\%}, 26.0{\%}, 49.1{\%}, 74.9{\%}, 100{\%}). The shock and particle velocities obtained from the UDE data were compared to the universal liquid Hugoniot (ULH) equation. It was found that the UDE data deviate below the ULH for water and trend upward with respect to the ULH with increasing ethanol fraction, finally deviating completely above the ULH for mixtures with mole fraction greater than or equal to 56{\%}. However, the ethanol/water mixture UDE data do not monotonically transition from below the ULH to above the ULH across the concentration range, but instead show increased deviation between ethanol mole fraction 7{\%} - 12{\%}. In contrast, the UDE data from the ideal liquid mixture are well behaved and agree with the ULH prediction across the concentration range. The deviations of the non-ideal ethanol/water data from the ULH are attributed to complex hydrogen bonding networks in ethanol/water mixtures that alter the compressibility of the mixture. [Preview Abstract] |
Tuesday, July 9, 2013 4:30PM - 4:45PM |
L7.00005: The Equation of State of Water in the MPa to TPa Regime J. Michael Brown The thermodynamic properties of water, in continual refinement on the basis of evolving experimental and theoretical methods, span an enormous range of volume, temperature, and pressure. A current generation equation of state can accurately represent experimental data below 100 MPa but fails to match within experimental uncertainties a body of high-pressure data. B-spline basis functions (piece-wise continuous polynomials) lend themselves to regularized linear and non-linear inverse techniques and can represent equation of state surfaces. Here, a sixth order tensor b-spline for the free energy is used to fit sound speeds, specific heats, densities, and thermal expansivities in accord with estimated uncertainties. This framework for the assimilation of data allows for flexible fitting to arbitrary precision. Once a system is adequately represented, revisions are easily accomplished in the face of new data or revised interpretations. The new equation of state fits low-pressure data as well as static and shock data extending to more than 100 GPa. Since this representation contains no theoretical assumptions, it provides an unbiased estimator for comparisons with theory. For example, super ionic behavior in the fluid phase is evaluated. [Preview Abstract] |
Tuesday, July 9, 2013 4:45PM - 5:00PM |
L7.00006: Warm dense water in 100 GPa regime Norimasa Ozaki, Tomoaki Kimura, Takuo Okuchi, Martin French, Tomoyuki Kakeshita, Mika Kita, Kohei Miyanishi, Ronald Redmer, Takayoshi Sano, Tomokazu Sano, Katsuya Shimizu, Tomoyuki Terai, Ryosuke Kodama We have experimentally measured the pressure-volume-temperature equation-of-state and the optical reflectivity of water, which matches with the interior condition of the water-rich super Earth. Transition between the warm dense fluid water and the electronically conducting fluid, where its physical and chemical properties are changing dramatically ($\sim$100 GPa range) has been explored with experiments that can directly measure the temperature of the system. It is done by focusing strong laser onto a preloaded water. Understanding of the inner structure of such unique super-Earths would be a key constraint on the origin and evolution of exoplanetary systems. [Preview Abstract] |
Tuesday, July 9, 2013 5:00PM - 5:15PM |
L7.00007: Thermodynamics of Dynamically Compressed Gases at Megabar Pressures Victor Gryaznov, Igor Iosilevskiy, Eugene Yakub, Vladimir Fortov Thermodynamic model based on ``chemical picture'' is applied to calculation of equation of state of warm dense hydrogen, deuterium and helium at submegabar and megabar pressure range. Strongly compressed fluid is considered as a multi-component strongly interacted mixture of atoms, molecules, ions and electrons. Nonidealty effects of Coulomb interaction of charged particles and short-range repulsion of atoms and molecules are included in thermodynamic functions as well as in effective shifts of ionization and dissociation equilibrium. Effects of free electrons degeneracy are taken into account in charge screening. The results of calculation of principal Hugoniots of hydrogen and deuterium at submegabar pressures are compared with experimental data and calculations by means of ab initio DFT-MD approach and calculations on the basis of non-empirical atom-atomic approximation. New calculations of Hugoniots of high density precompressed deuterium at megabar pressures and extended density range are presented. The results of calculations of thermodynamic functions for isentropic compression of helium at multi-megabar pressures are presented and compared with experimental data and DFT-MD data. Contribution of various plasma effects, such as dissociation of molecular phase, ionization, interparticle interaction, degeneracy effects of free electrons whole range of pressures covered by the experiments are analyzed and discussed. [Preview Abstract] |
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