Thermal Conductivities of Some Polyatomic Gases at Moderately High Temperatures

Abstract

Thermal conductivities of nitrous and nitric oxides, carbon tetrafluoride, silicon tetrafluoride, sulfur hexafluoride, and boron trifluoride have been determined at moderately high temperatures, ranging from about 60° to about 400°C in different cases. The experimental results (including the collision numbers for rotational relaxation) are compared with the results of several different approximate theories of heat conduction in polyatomic gases, and with values obtained for several modifications of the rough‐sphere model. Generally, the Mason—Monchick theory is found to give good agreement with experiment if the average rotational collision number in the temperature range is treated as an adjustable parameter. For N₂O and SF₆, the modified Eucken expression based on the diffusion mechanism theory of heat conduction was successful in accounting for the experimental results over the entire temperature range.