The MGGB equation-of-state for multifield applications: a numerical recipe for analytic expression of sesame EOS data

Kashiwa, B. A.

Los Alamos National Laboratory

关键词: Specific Heat;    Saturation;    Compressibility;    Free Energy;    Thermodynamics;   

DOI  :  10.2172/991234
RP-ID  :  LA-14421
RP-ID  :  DE-AC52-06NA25396
RP-ID  :  991234

美国|英语

来源: UNT Digital Library

【 摘 要 】

Abstract A thermodynamically consistent and fully general equation–of– state (EOS) for multifield applications is described. EOS functions are derived from a Helmholtz free energy expressed as the sum of thermal (fluctuational) and collisional (condensed–phase) contributions; thus the free energy is of the Mie–Gr¨uneisen1 form. The phase–coexistence region is defined using a parameterized saturation curve by extending the form introduced by Guggenheim,2 which scales the curve relative to conditions at the critical point. We use the zero–temperature condensed–phase contribution developed by Barnes,3 which extends the Thomas–Fermi–Dirac equation to zero pressure. Thus, the functional form of the EOS could be called MGGB (for Mie– Gr¨uneisen–Guggenheim–Barnes). Substance–specific parameters are obtained by fitting the low–density energy to data from the Sesame4 library; fitting the zero–temperature pressure to the Sesame cold curve; and fitting the saturation curve and latent heat to laboratory data,5 if available. When suitable coexistence data, or Sesame data, are not available, then we apply the Principle of Corresponding States.2 Thus MGGB can be thought of as a numerical recipe for rendering the tabular Sesame EOS data in an analytic form that includes a proper coexistence region, and which permits the accurate calculation of derivatives associated with compressibility, expansivity, Joule coefficient, and specific heat, all of which are required for multifield applications. 1