Linking Thermal Conductivity and Self-Diffusion Coefficient with a Simple Dimensionless Calorimetric Parameter for Saturated Liquids

Abstract

Thermal conductivity and self-diffusion coefficients for saturated liquids were linked with a simple dimensionless calorimetric parameter (DCP) in this work. Similar to the DCP approach with the viscosity proposed in our previous research study, it was found that by scaling the thermal conductivity and self-diffusion coefficient, linear relations of these two transport properties with the DCP could be exhibited. On this basis, two-parameter formulas for calculating the thermal conductivity and self-diffusion coefficient through the DCP were put forward. Meanwhile, the slope and intercept of the linear formula for thermal conductivity were found to be one-dimensionally related, while the slopes of the self-diffusion coefficient equations fell in the narrow interval of −1.64 ± 0.21, revealing a quasi-universality for various nonassociation fluids. The new DCP-based model for calculating thermal conductivity was evaluated and validated with the experimental data of 21 pure fluids representing different molecular structures. The average absolute deviation and the maximum absolute deviation between the linked thermal conductivities and the literature data were within 5.04 and 8.30%, respectively. This work provided novel methods for calculating the thermal conductivity and self-diffusion coefficient of saturated liquids.