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In our previous work (Ind. Eng. Chem. Res. 2023, 62, 18736-18749), a modeling approach was developed to calculate all the essential thermophysical properties, including density, phase equilibria, heat capacity, entropy, enthalpy, viscosity, and thermal conductivity, of lubricant oils. This approach treats oil as a quasi-pure fluid, sets up a simple set of equations for the essential properties, and develops a parameter-fitting procedure using a minimal set of experimental data (fewer than 20 and at least 12 data points). This approach can be easily extended for mixture (e.g., oil + refrigerant) property prediction. Calculations using this approach generally agree with experimental data within the experimental uncertainty, except for up to 3% of quasi-pure oil density, 5% of the mixture’s density, and several hundred percent of the mixture’s viscosity. In this work, a new cubic equation of state (EoS) recently developed by us was adopted to replace the initially used Patel-Teja-Valderrama (PTV) EoS. As a result, for density, relative deviations were reduced to approximately 1.5% for quasi-pure oil and generally to 3.0% for mixtures. For viscosity, an improved residual entropy scaling (RES) approach was used, and a van der Waals-type mixing rule containing one adjustable parameter, which could be fitted to experimental data, was applied to the mixture’s viscosity prediction. As a result, relative deviations for viscosity could be significantly reduced; however, they are still at the level of a few tens up to hundreds of percent. Careful evaluations of the mixture’s viscosity data revealed that the uncertainty of the experimental data could be significantly higher than expected, and there is an apparent lack of high-quality viscosity data of oil + refrigerant mixtures. All fitted parameters of oils were implemented in OilMixProp 1.0, our self-developed software package, which was used for all calculations reported in this work (contact the authors; it is free for academic institutions).

Schlagwörter: thermophysical property, modelling, lubricant oils, refrigerants, mixtures