THERMAL CONDUCTIVITY OF MIXTURES OF HYDROGEN WITH NITROGEN.

A report is presented on absolute measurements of the thermal conductivity of mixtures of hydrogen and nitrogen in the pressure range 0. 7 to 10 MPa at a nominal temperature of 27. 5 degree C. The experimental results have an estimated uncertainty of plus or minus 0. 3%. The mixture thermal conductivity in the limit of zero-density can be described with the aid of the available kinetic theory only if empirical adjustments are made to some of the collision-integral ratios characteristic of the unlike interactions. The need for these adjustments is taken as evidence that the available kinetic theory formulae are not sufficiently accurate for gas mixtures in which the mass ratio of the molecules is large. At elevated densities the calculation scheme of Mason and his coworkers cannot provide a description of the experimental data within their uncertainty, even when empirical adjustments of a parameter characteristic of the unlike interactions are allowed.