Thermal expansion and stability limits of generalized van der Waals fluids

Journal Article · Thu Jul 07 00:00:00 EDT 1994 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100078a034· OSTI ID:7243350

Chakravarthi, A S; Debenedetti, P G; Yeo, S D ^[1]; Sastry, S ^[2]

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1. Princeton Univ., NJ (United States)
2. Boston Univ., MA (United States)

Generalized van der Waals equations of state can exhibit density anomalies, as characterized by a negative thermal expansion coefficient in some region of the phase diagram, when either the hard core volume, b, or the mean field attractive parameter, a, are made temperature-dependent. If b decreases as the temperature increases, negative thermal expansion occurs at all temperatures. At a given temperature, the liquid becomes anomalous when the pressure is increased; hence the P-T projection of the locus of density maxima has positive slope. The locus of density maxima extends to zero temperature when b is finite at T = 0, and it terminates at a minimum temperature if b diverges at T = 0. If, on the other hand, a increases with temperature while the core volume remains constant, generalized van der Waals fluids exhibit density anomalies that disappear at high pressure. Hence, in this case the locus of density maxima has a negative slope in the P-T plane. The liquid spinodal is re-entrant both when a increases as the temperature increases and when b increases as the temperature decreases, becoming infinite at T = 0. 38 refs., 20 figs., 1 tab.

• DOE Contract Number: FG02-87ER13714
• OSTI ID: 7243350
• Journal Information: Journal of Physical Chemistry; (United States), Vol. 98:27; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
LIQUIDS
EQUATIONS OF STATE
THERMAL EXPANSION
THERMODYNAMIC PROPERTIES
VAN DER WAALS FORCES
HEAVY WATER
MATHEMATICAL MODELS
SILICA
WATER
CHALCOGENIDES
EQUATIONS
EXPANSION
FLUIDS
HYDROGEN COMPOUNDS
MINERALS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SILICON COMPOUNDS
SILICON OXIDES
360606* - Other Materials- Physical Properties- (1992-)
990200 - Mathematics & Computers
661300 - Other Aspects of Physical Science- (1992-)