Thermal Conductivity of Argon in the Dense Gaseous and Liquid Regions

Abstract

Thermal conductivities for argon in the dense gaseous state were determined at 6.2°, 20.7°, 25.0°, and 48.8°C for pressures up to 10 340 psia, using a coaxial cylindrical cell. These values were found to be in good agreement with thermal conductivities reported by others and when expressed as residual quantities, k—k*, unique relationships resulted with ρR and the (∂PR/∂TR)ρR. These relationships were independent of temperature and pressure and included both the dense gaseous and liquid states. The Enskog equation for the effect of pressure on thermal conductivity,k/k*=bρ[(1/bρχ)+(6/5)+0.7574bρχ],,has been applied to the data of this study and of others for the dense gaseous and liquid regions, to obtain values of b. These values were found to be independent of pressure and to depend upon temperature as follows: bρc=1.06/TR23. For these calculations, bρχ values were established from PVT data for argon. The experimental values obtained in this study were used to determine (k/ρ)min for each temperature, which were used in conjunction with the Enskog equation to produce thermal conductivities at elevated pressures. Values calculated with (k/ρ)min produced an average deviation of 1.2%, whereas the values resulting from bρc=1.06/TR23 gave an average deviation of 2.0%.