MODEL OF THE EVOLUTION OF A BINARY HOMOGENEOUS SOLUTION FILM UNDER THERMAL ACTION

Abstract

The research on the motion of liquid films has recently become increasingly important, which is associated with the expanding field of their practical application. For example, the promising methods of cooling include the technologies based on the evaporation of a thin layer of liquid. Based on the Marangoni effects, optical elements of medical diagnostics systems can be developed, the performance of which can be quickly reconfigured for the necessary tasks in comparison with the currently used movable lenses. Many authors in Russia and abroad are engaged in a comprehensive theoretical study of film flows, which should not lag behind the studies of the possibilities of their application. At the same time, the motion of films of a binary homogeneous solution has not been studied enough, and this is the object of this study. This paper considers the behavior of a liquid film containing a volatile component when it is heated. The importance of taking into account the Laplace pressure jump at the interface is indicated, as well as the effect of surface curvature on the saturated vapor pressure. Formulation of the problem is formalized in a limited volume. The stability of the numerical scheme was investigated by the harmonics method. The results confirm the reliability of the model by testing it on a number of problems with analytical solutions: preservation of a liquid volume when a film in a gravity field touches a vertical wall; determination of the profile of the liquid layer with uneven heating of the substrate; mass balance at uniform heating and cooling.