Key words: microscopic dynamics of liquids and gases, superhigh pressures, fluids viscosity, supercritical technologies
Up to date supercritical technologies use the fluids like CO2, H2O etc. at temperatures
and pressures close to the corresponding critical points. It is not clear up to date if
the near-critical fluctuations are important for the solubility processes and chemical
reactions in the fluids. Meanwhile recently we have shown that at the temperatures and
pressures much higher than the critical ones there are qualitative changes of almost
all fluid properties. The paper briefly summarizes the last results of the search and
study of P,T-parameters of the changes of dynamics in supercritical fluids. We found
that actually these parameters correspond to the narrow band — «Frenkel line». The
crossing this line during temperature increase corresponds to the disappearance of
the shear rigidity of a fluid at all available frequencies. Thus Frenkel line can be considered
as a boundary between a liquid and a dense gas at superhigh pressures far from the
critical point. Very recently we have proposed very simple and rigorous criterion to
find Frenkel line position based on the analysis of autocorrelation function of particle
velocities. We plan to use the data of the Frenkel line parameters for real fluids to push
supercritical technologies to the superhigh pressure region far from the critical point.
doi:10.1134/S199079311408003X