Absolute determination of the thermal conductivity of the noble gases and two of their binary mixtures as a function of density

Abstract

The paper reports absolute measurement of the thermal conductivity of the monatomic gases helium, neon, argon, krypton and xenon and of binary mixtures of helium and neon and argon and krypton. The measurements have been carried out in a transient hot-wire apparatus at 35 °C and in the pressure range 0.5–10 MPa. The overall uncetainty in the reported thermal conductivity data is estimated to be ±0.2%, an estimate which is confirmed by a comparison with low density viscosities for the same gases.The experimental thermal conductivity for each system studied conforms to a polynomial expansion in density. It is found that the data for the binary mixtures in the limit of zero density can only be adequately represented if third-order kinetic theory expressions are employed. A recently proposed scheme for the evaluation of the thermal conductivity of dense gas mixtures is found to represent the data for argon + krypton adequately. However, for helium + neon mixtures the proposed scheme required modifications in order to provide a satisfactory description of the experimental data.