The thermal conductivity of nonpolar substances in the dense gaseous and liquid regions

Abstract

In 1949 Gamson (13) produced a reduced state correlation from available thermal conductivity data in which the reduced thermal conductivity, k/kc, is plotted against reduced temperature and pressure. Experimental data, which were subsequently obtained, were found to deviate considerably from values resulting from Gamson's correlation ( 4 5 ) . Comings and Nathan (9) combined the Enskog relationships for viscosity and thermal conductivity to obtain an expression for the ratio, k/k", in terms of the viscosity ratio, p /~" , and the quantity, y. In the resulting relationship, the effects of the internal degrees of freedom of the molecules are neglected. Values of y were obtained from experimental P-V-T data as suggested by Enskog (lo), and experimental and calculated viscosities were used to develop a correlation between k/k* and reduced temperature and pressure. Lenoir and Comings (29) found that their experimental thermal conductivities for argon, nitrogen, methane, ethylene, and carbon dioxide were in good agreement with those resulting from the correlation of Comings and Nathan. Lenoir, Junk, and Comings (30) used their experimental values for nitrogen, methane, and argon, and the values obtained previously by Lenoir and Comings to develop a new correlation for k/k* which is very similar to that of Comings and Nathan, except that it predicts higher values for conditions in the vicinity of the critical point. Thermal-conductivity values determined by Lenoir, Junk, and Comings for ethane were found to be inconsistent with corresponding values resulting from their correlation, as were the subsequent values obtained by Leng and Comings (28) for propane and those of Kramer and Comings (27) for n-butane. Therefore, it would be desirable to develop an improved correlation for thermal conductivity which is also applicabIe to a wider range of substances.Jossi, Stiel, and Thodos (20) have obtained reliable expressions for the viscosity of pure substances in the dense gaseous and liquid phases by the use of a relationship between the residual viscosity, p -EL*, and density, along with a dimensional analysis approach. Thodos and coworkers (22, 38, 47, 48) have found that the residual thermal conductivity, k -k*, is a unique function of density for all the substances investigated. A theoretica1 basis for such a dependence has been provided by Predvoditelev (41). Therefore, in the present study an approach similar to that of Jossi, Stiel, and Thodos for viscosity has been utilized to develop a generalized correlation for the thermal conductivity of nonpolar substances by the use of the residual relationship for this property and dimensional analysis.Leonard I . Stiel is with Syracuse University, Syracuse, New York. DIMENSIONAL ANALYSISSeveral investigators have suggested that the thermal conductivity in the dense gaseous and liquid regions is dependent on Cp, the heat capacity (10, 12). If th' is variable is included in a dimensional analysis treatment of the residual relationship, the resulting expression would indicate th...

Estimation of thermal conductivity of pure gases by using artificial neural networks

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“…Stiel and Thodos [22] For pure non-hydrocarbon nonlinear molecules gases at low pressure (up through 1 atm).…”

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