Key words: thermal conductivity, critical amplitudes, critical point, supercritical fluid, crossover model, heat transfer coefficient
The experimental bases and some aspects of the theory and modeling of transport properties
(thermal conductivity, viscosity, thermal diffusion coefficient) of fluids in the critical and
supercritical regions are considered. Information on the critical thermal conductivity
anomaly (theory and experiment) is analyzed in detail. A brief historical reference is
given on the first experiments on thermal conductivity in the critical region, carried out
mainly by Soviet researchers. The features of measuring the thermal conductivity in the
critical region and various interpretations of its critical anomalies are considered. Various
approaches to describing the critical anomaly in the transport properties of supercritical
fluids, primarily the crossover approach, are discussed. The possibility of representing
critical thermal conductivity anomalies described on the basis of the coupled modes
theory of dynamic critical phenomena, in a simplified version with two critical amplitudes
and with one «cutoff» parameter \(\overline q_D\) (boundary value of the wave number), characteristic
of a particular fluid, is shown. A procedure for determining these specific parameters is
developed on the basis of the corresponding states princi ple. This made it possible to
develop a universal method for describing critical anomalies of transport properties of
supercritical fluids. In a pulse experiment, conditions were found under which anomalies
of properties did not manifest themselves.
doi:10.1134/S1990793121070022