The viscosity of gaseous mixtures containing krypton

Abstract

The paper describes measurements of the viscosity of binary mixtures of krypton with CO2, CH4, CF4, and SF6 and of the two ternary mixtures, He–Ne–Kr and He–Ar–Kr. The measurements were performed in a high-precision oscillating disk viscometer at atmospheric pressure. The observations extend over the temperature range 25–200 °C for Kr–CH4 and Kr–SF6, 25–400 °C for Kr–CF4, 25–500 °C for Kr–CO2 and He–Ne–Kr, and 25–600 °C for He–Ar–Kr. The uncertainty in the reported viscosities ranges from one of ±0.1% at 25 °C to 0.3% at 600°C. In the case of all of the binary mixtures it is shown that the kinetic theory collision integral for viscosity can be represented by the universal functional Ω22, characteristic of the extended law of corresponding states developed by Kestin, Ro, and Wakeham. The values of the two scaling parameters σij and εij for each interaction, which secure the optimum representation of this kind, are presented. Diffusion coefficients for each binary system are also derived from the experimental data. In the case of the ternary mixtures it has already been established that the viscosity collision integral for each binary interaction conforms to the extended law of corresponding states. Consequently, the present measurements for these systems serve as a test of the ’’predictive’’ capability of a scheme based upon the Curtiss–Hirschfelder expression for the viscosity of multicomponent mixtures and the same law of corresponding states. The calculated and experimental values for the viscosity of these mixtures agree to within ±0.3%.