Simple Direct Relationship between Scaled Viscosity and a Dimensionless Calorimetric Parameter for Saturated Liquids

Abstract

The relationship between the transport property and thermodynamic property was explored in this paper. More specifically, a dimensionless calorimetric parameter (DCP) was employed in order to predict the viscosity of different fluids for the first time. It was found that a strong linear correlation between the macroscopically scaled viscosity and the DCP of different fluids in saturated liquid states takes place. Additionally, the values of linearly correlated slopes K for each fluid were found to be in a narrow range (0.411 ± 0.034). Based on this, a quasi-universal viscosity prediction model was proposed. Fourteen fluids representing different molecular structures were selected, and the reliability of the theoretical framework was verified through comparison with experimental data. The results indicated that the correlation approach was very satisfactory with a maximum average absolute deviation (AAD) of 4.40%. Furthermore, by correlating the slopes with the fluid-specific parameters, a generalized function with no adjusting parameters was finally established. Compared with experimental data, the AADs were all located within 7.23%, except those for R125 and R143a. This work provides a convenient calculation method for the estimation of the transport property (viscosity) of different fluids only from the respective thermodynamic properties.