EXPERIMENTAL AND THEORETICAL-STUDY OF THE EQUATION OF STATE OF CHF3 IN THE NEAR-CRITICAL REGION

The pressure-density-temperature (p-rho-T) surface of CHF3 has been measured in the near-critical region by using an expansion-type apparatus. The data overlap with other previously published data for the classical region and seem compatible with results already reported for the critical region. The abilities of two revised and extended scaling equations of state for predicting the data have been tested. The equation of Senger et al. describes the data satisfactorily, though in a quite limited region around the critical point. The results obtained with the equation of Anisimov et al. lead to similar results, though its applicability is restricted to a smaller region around the critical point. A classical equation with modified thermodynamic fields, leading to the correct scaling asymptotic behavior, describes the near-critical data as well as the equation of Sengers et al. while giving a better description of the crossover region.