Density measurements on (argon + carbon dioxide) over the temperature range from (253.15 to 453.15) K at pressures up to 20 MPa

The density of (argon + carbon dioxide) mixtures was measured over the temperature range from (253.15 to 453.15) K with pressures up to 20 MPa, utilizing a single-sinker densimeter adapted for measurements in gas mixtures; the apparatus and a detailed uncertainty analysis are presented. Four gravimetrically prepared mixtures with approximately (0.50 and 0.75) mole fraction carbon dioxide were investigated. The relative combined expanded uncertainty (k = 2) of the measured densities ranged from (0.059 to 0.127) % and (0.060 to 0.150) % for the 0.50 and 0.75 mole fraction carbon dioxide mixtures, respectively. The results are compared to experimental data from the literature and to different equations of state. The deviations from the EOS-CG-2021, the current state-of-the-art multi-component mixture model for combustion-gas-like mixtures, ranged from (−2.79 to 0.19) % and (−0.53 to 0.69) %, respectively; especially at low temperatures and high pressures, systematic deviations from the equation of state were found.