HTHP EA HomeIssue Contents

Dynamic viscosity of azeotropic and quasi-azeotropic mixtures of organic compounds
Giovanni Latini, Giovanni Nicola, Giorgio Passerini

Azeotropic and quasi-azeotropic mixtures of organic compounds are becoming the most effective candidates as replacement fluids. Heat and mass transfer phenomena in organic compound mixtures have been theoretically studied from several different points of view. Despite these efforts, theoretical models are frequently inaccurate while empirical methods are usually more accurate but they are often specialised and tuned to cover a small number of compounds and/or a limited temperature range. Based on the development of effective prediction formulas for several families of pure organic compounds, the problem of the evaluation of mixture dynamic viscosity is approached from a rather different point of view. Azeotropic mixtures are treated as pure compounds rather than a combination of several pure substances, and a single, specialised formula for the evaluation of saturated liquid dynamic viscosity is developed. The prediction method requires the knowledge of few equilibrium properties of the mixture to be analysed thus becoming a simple and powerful tool for exhaustive analysis of alternatives. It has been tested against experimental data leading to deviations far below those required for engineering purposes.

Full Text (IP)