The thermal conductivity of liquid mixtures at elevated pressures

Abstract

This paper reports new, absolute measurements of the thermal conductivity of liquid mixtures of n-heptane and isooctane in the pressure range 0.1 to 430 MPa for temperatures of 307.85 and 337.15 K. The results represent a preliminary investigation of the advantages of attempting to describe the isothermal composition dependence of the thermal conductivity of liquid mixtures along isochores, rather than isobars as has been traditional. However, no significant differences were found between the composition dependences in the two circumstances, possibly due to the lack of experimental data on the density of these mixtures. The availability of a theoretical description of the isochoric composition dependence suggests that this is the most appropriate description which reinforces the need for further high-pressure measurements of the thermal conductivity and density.