Experimental data and procedures for predicting thermal conductivity of binary mixtures of nonpolar gases

Abstract

The thermal conductivities of Ne, Ai, Kr, Xe, Hz, 02 Nz, and 02 are measured using a thick hot-wire metal cell at five temperatures in the range 40-175OC. The solution of the heat balance equation as developed by Oldham andvluchsinger is employed, and we estimate an accuracy of 1-2% in our recommended absolute conductivity values. In this temperature range, the thermal conductivities of the binary systems Ne-Hz, Ne-Nn, Ne-02, Hz-Dz, Nz-Dz, Hz-Nz, N2-02, Kr-Hn, Xe-Hz, Xe-Dz, and Xe-Ar are also determined as a function of composition. On the basis of these experimental data, the methods of prediction of thermal conductivity of mixtures due to Hirschfelder, Mason and Saxena, Mathur and Saxena, Lindsay and Bromley, Ulybin et al., and Burgoyne and Weinberg are examined with a view to ascertain their relative accuracies. The framework of Chapman-Enskog kinetic theory in conjunction with the experimental data on thermal conductivity is used to generate the diffusion and viscosity coefficients for Xe-Ar, Xe-Dn, Ne-Hz, Ne-Nn, and Ne-02, as representative systems. Recently Saxena and Gupta (26) have reported experimental thermal conductivity data on eight pure gases, four of their binary, two ternary and two quaternary systems as a function of composition. The measurements were taken on a metal hot-wire cell with a thick platinum wire as a hot surface, and at temperatures of 40, 65, and 93'C. Here we report the thermal conductivities of the binary systems Ne-H2, Ne-N2, Ne-On, HZ-Dn, NZ-DZ, Hn-Nz, Nz02, Kr-Hz, Xe-H2, Xe-D2, and Xe-Ar as a function of composition and of the related eight pure gases at 40°, 65, 930, 950, 135, and 175C, using the same hot-wire cell. The details of the experimental arrangement, procedure of calculation, and comparisons of the experimental conductivity values with some of the semitheoretical procedures are given in the following sections. EXPERIMENTAL