J. Luettmerstrathmann et Jv. Sengers, TRANSPORT-PROPERTIES OF FLUID MIXTURES IN THE CRITICAL REGION, International journal of thermophysics, 15(6), 1994, pp. 1241-1249
Transport properties of fluid mixtures exhibit anomalous behavior near
the vapor-liquid critical line. These anomalies are a result of long-
range fluctuations in the system in the vicinity of a critical point.
We use mode-coupling theory to describe the critical enhancements of t
he thermal conductivity, the viscosity, the mutual diffusivity, and th
e thermal-diffusion coefficients of binary mixtures. The resulting exp
ressions not only are valid in the asymptotic critical region but also
describe the crossover to regular behavior far away from a critical p
oint. The crossover functions depend on the thermodynamic properties o
f the mixtures, background values of all transport coefficients, and t
wo concentration-dependent cutoff wave numbers. We compare the propose
d crossover model with experimental thermal-conductivity data for mixt
ures of carbon dioxide and ethane in the critical region and find good
agreement between theory and experiment.