Absolute Determination of the Thermal Conductivity of Argon at Room Temperature and Pressures Up to 68 Mpa

The thermal conductivity of argon at room temperature and for pressures up to 68 MPa has been measured with a transient hot-wire technique in order to assess the accuracy of an instrument of this type. The data are presented for a nominal temperature of 300.65 K and comparison with other authors shows that our data is accurate to within ± I percent, and it is the most accurate set of data for pressures above 35 MPa. Experimental evidence of a thermal conductivity enhancement near the critical density for a temperature about twice the critical temperature is herein reported. The experimental data were compared with the values predicted by the hard sphere model and it has been found that the theory gives values that are about 4 percent lower than the experimental ones in the density range 0-400 kg/m and about 1 to 2 percent lower in the high density region 400-825 kg/m 3 •