The Viscosities of Dilute Kr, Xe, and CO$_2$ Revisited: New Experimental Reference Data at Temperatures from 295 K to 690 K

Abstract

Previously reported, but also unpublished experimental data of our group for the viscosities of dilute krypton, xenon, and carbon dioxide, obtained in the range from 295 K to a maximum of 690 K using oscillating-disk viscometers, were re-evaluated and corrected or extrapolated to the limit of zero density ($\eta _0$). The combined standard uncertainty of the data is 0.1 % at room temperature and 0.2 % at higher temperatures. For krypton and carbon dioxide, our $\eta _0$ data were compared with $\eta _0$ values theoretically calculated using the kinetic theory and highly accurate ab initio potentials for the krypton atom pair and the CO$_2$ molecule pair, but also with recent experimental $\eta _0$ data from the literature. Our data for krypton differ up to 690 K from the theoretical values by $-0.10\,\%$ to $+0.28\,\%$, whereas that of Lin et al. (Fluid Phase Equilib. 418:198, 2016) show deviations of +(0.04 to 0.20) % at temperatures from 243 K to 393 K, in each case proving that experiment and theory are in consistent agreement. The re-evaluated $\eta _0$ data for xenon were compared with recent data from the literature and with calculated values resulting from the HFD-B potential for xenon via the corresponding-states principle to verify that they are reference values. For carbon dioxide, $\eta _0$ values obtained from 26 re-evaluated isotherms and from eight isotherms of Schäfer et al. (J Chem Thermodyn 89:7, 2015) between 253 K and 473 K are mutually consistent with ab initio calculated and subsequently scaled viscosity values of Hellmann (Chem Phys Lett 613:633, 2014). The isotherms of Schäfer et al. are especially suitable for determining the initial density dependence of the viscosity. Concomitantly inferred reduced second viscosity virial coefficients were checked against two theoretical approaches of the Rainwater–Friend theory.