Viscosity Behavior of Two Mixtures of CO_2 and Lubricant Oil

摘要

Experimental data on the viscosity of mixtures of CO_2 and lubricant oil were acquired and correlated using an excess-property approach based on the classical Eyring liquid viscosity model. Two oils of different types and viscosity grades (AB ISO 32 and mineral ISO 50) were evaluated at temperatures ranging from 40 to 82°C. The excess activation energy for viscous flow was successfully correlated as a function of temperature and concentration using Redlich-Kister polynomial expansions with up to three terms. Large departures from the ideal solution viscosity behavior have been identified in both mixtures. The nature of the observed deviations has been explored in the light of their dependence on temperature, refrigerant concentration and oil type.