Article,
On the extrapolation behavior of empirical equations of state
International Journal of Thermophysics, 18 (6): 1415--1443 (November 1997)
DOI: 10.1007/BF02575343
Abstract
Generally, the extrapolation behavior of empirical equations of state is regarded as poor, but it can be shown that state-of-the-artequations of state yield reliable results well beyond the range where they were fitted to experimental data. During the pastyears a new generation of highly accurate equations of state which yield reasonable results even up to the limits of chemicalstability of the considered substances has been developed. In this paper, the positive influence of recent methods for thedevelopment of equations of state on their extrapolation behavior is discussed. The influence of the mathematical structureon the extrapolation characteristics is analyzed and requirements for a reasonable behavior up to extreme temperatures andpressures are formulated. As possible ways for assessment of the extrapolation behavior of an equation of state, comparisonswith experimental data at very high pressures and temperatures and with theoretically predicted features of the so-called“ideal curves�? of a fluid are discussed. Finally, the current status of our knowledge of the extrapolation behavior of empiricalequations of state is summarized and its shortcomings are pointed out.
