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Résumé :
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Alternative working fluid mixtures containing hydrofluoroethers, hydrofluorocarbons, alkanes, alcohols, ketones, and esters widely used as process fluids generally exhibit azeotropes, high nonideality, and association effects. In this work, the vapor−liquid equilibria for these mixtures are predicted using a combination of the Soave−Redlich−Kwong equation of state, zero reference pressure GE−EoS mixing rules, and the UNIFAC group contribution model. A new functional group assignment strategy was developed, and the model interaction parameters between groups were obtained from selected binary vapor−liquid equilibria data to give fairly good agreement between the calculated results and the experimental data. The method is also extended to ternary systems for VLE representations in a totally predictive manner with only the molecular structures, the critical parameters, and the acentric factors of the pure components needed.
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