Modeling Thermophysical Properties of Carbon Dioxide: Performance Comparison and Assessment

Abstract Although many mathematical models have been developed for predicting the density, viscosity, and thermal conductivity of CO 2 , their accuracy and applicability have not been sufficiently established in the gas/liquid and supercritical regions and, in particular, in the region around the critical point. To understand their performances, the models are compared and analyzed, including (i) the cubic equations of state, multi‐parameter equations, and the Helmholtz free energy‐based model for density, (ii) residual theory‐ and regression‐based models for viscosity and thermal conductivity, and (iii) artificial intelligence‐based models (neural networks/machine learning) for these properties. A technical assessment is then performed. The results may provide a positive reference for determining the thermophysical properties of CO 2 .