The Transport Properties of Carbon Dioxide

TLDR

The equations are based on a critically assessed body of experimental data for consistency and agreement with theory. The paper presents new, representative equations for CO₂ viscosity and thermal conductivity and identifies unresolved viscosity data inconsistencies that require new measurements. The correlations cover 200–1500 K for viscosity and 200–1000 K for thermal conductivity up to 100 MPa, with tables provided to aid implementation. The authors replace inconsistent low‑density high‑temperature thermal conductivity data with theoretical predictions, predict liquid‑phase thermal conductivity due to scarce data, model critical‑region enhancements with a single‑parameter equation, and report correlation uncertainties from ±0.3 % for dilute‑gas viscosity to ±5 % for liquid‑phase thermal conductivity.

Abstract

The paper contains new, representative equations for the viscosity and thermal conductivity of carbon dioxide. The equations are based in part upon a body of experimental data that have been critically assessed for internal consistency and for agreement with theory whenever possible. In the case of the low-density thermal conductivity at high temperatures, all available data are shown to be inconsistent with theoretical expectation and have therefore been abandoned in favor of a theoretical prediction. Similarly, the liquid-phase thermal conductivity has been predicted owing to the small extent and poor quality of the experimental information. In the same phase the inconsistencies between the various literature reports of viscosity measurements cannot be resolved and new measurements are necessary. In the critical region the experimentally observed enhancements of both transport properties are well represented by theoretically based equations containing just one adjustable parameter. The complete correlations cover the temperature range 200 K≤T<1500 K for viscosity and 200 K≤T≤1000 K for thermal conductivity, and pressures up to 100 MPa. The uncertainties associated with the correlation vary according to the thermodynamic state from ±0.3% for the viscosity of the dilute gas near room temperature to ±5% for the thermal conductivity in the liquid phase. Tables of the viscosity and thermal conductivity generated by the representative equations are provided to assist with the confirmation of computer implementations of the calculation procedure.