PREDICTING FLUID VISCOSITY BY ENTROPY PRODUCTION

In this paper an approach is developed for predicting fluid viscosity, specially for its density dependence, by the balance of entropy produ ction and entropy flow in an open system near the equilibrium stationa ry state. The expressions for entropy production and entropy flow are obtained by non-equilibrium statistic thermodynamic principle. So a fo rmula is obtained for viscosity coefficient that gives a density depen dence proportional to entropy derivative with respect to density. The proportional amplitude is found to be a simple function of temperature . The theory in some special cases is compared with theory models for viscosity such as Hildebrand fluidity model and the modified Enskog th eory (MET). The model is verified by experiment viscosity of a number of fluids including rare gases, carbon dioxide and hydrocarbons, and f ound in good agreement with experiment data from literature in liquid, gas and supercritical region. The absolute average deviation is 4.20% for 11691 data points of 24 fluids. (C) 1997 Elsevier Science B.V.