Calculation of the effective concentration for nitrogen and krypton in the surface layer of the cryogenic liquids solutions (N2/Ar) and (Kr/Xe).

A method for calculating the density, effective concentration of surface layer and surface tension of cryogenic liquids solutions: nitrogen-argon (N2/Ar) and krypton-xenon (Kr/Xe), is proposed in the present report. Values of effective surface layer thickness have been obtained. Analysis of the surface layer structure has been made. An investigation has been carried out with help of a gradient theory (GT) in combination with cubical equation of state (EOS) in single-fluid approach. A method of determining of the EOS coefficients is also proposed. As a result it was found that the difference between component concentration in the surface layer and in the bulk liquid phase of the solution increases when temperature decreases. Obtained results are important for the experimental investigation of the properties of solutions and for thermodynamic modeling of phase equilibria and prediction of the surface tension of solutions.