THERMAL-CONDUCTIVITY OF SOME MIXTURES OF MONATOMIC GASES AT ROOM-TEMPERATURE AND AT PRESSURES UP TO 15-MPA

The paper reports measurements of the thermal conductivity of eight gaseous mixtures of monatomic gases. The group of systems studied consists of three binary mixtures of neon and argon, four binary mixtures of helium and argon and a ternary mixture of neon, argon and krypton. The measurements have been carried out in a transient hot-wire instrument at 27.5°C and within the pressure range 0.5-15 MPa. The accuracy of the experimental data is estimated to be one of ±0.2%. The experimental data for each mixture as a function of density are represented, within their uncertainty, by a polynomial of second degree in density. The thermal conductivity data in the limit of zero density for the Ne-Ar and Ne-Ar-Kr systems can be represented by the first-order kinetic theory formulae together with the universal functional of the extended law of corresponding states developed by Kestin, Ro and Wakeham. Furthermore, for Ne-Ar the data are shown to be thermodynamically consistent with viscosity measurements on the same system. However, in the case of He-Ar, a similar representation of the experimental data is found to be inadequate. This result is attributed to the poor convergence of the kinetic theory formulae for the thermal conductivity of a binary gas mixture composed of species having a large molecular mass ratio. © 1979.