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

Abstract

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 3 and about 1 to 2 percent lower in the high density region 400-825 kg/m 3 •

A Transient Hot Wire Thermal Conductivity Apparatus for Fluids

“…this apparatus is 1. percent lower than other authors [30]. Oxygen: this apparatus is 1-2 percent lower than other authors [26].…”

“…Results obtained subsequently on argon have already been published [30]. For helium a single pseudo isotherm was measured at a nominal temperature of 307 K with pressures up to 68 MPa.…”

“…The accuracy of the measurement can in principle be estab~ished from the measurements and certain theoretical considerations, i.e., for the rare gases the Eucken factor [7]. For argon [30] the 0.3 percent obtained in the low density extrapolation was considered a fortunate coincidence and an overall accuracy of ± 1 percent was claimed. For the results on helium in table 4 the low density extrapolation yields a result which is 1.8 percent low.…”

Experimental thermal conductivity values for hydrogen, methane, ethane and propane

“…The measurements were made with a transient hot wire thermal conductivity apparatus [l] 1 which has been tested with nitrogen [1], helium [1] and argon [2,3].…”

Experimental thermal conductivity values for mixtures of methane and ethane

“…The thermal conductivity of a 70/30 methane-ethane mixture The measurements were made with a transient hot wire thermal conductivity apparatus [3] which has been tested with nitrogen [3], helium [3] and argon [4,5]. The system has been used previously to measure the thermal conductivity surfaces of oxygen [6], hydrogen [7,8,9,10], methane [10,11], ethane [10,12] and propane [10,13].…”