Thin Film Thermocapillary Motion of Binary Alcohol-Containing Solution

Abstract

Interphase convection is a widespread phenomenon that occurs in various branches of technology, including chemical technologies. The greatest interest in the case of thin liquid films is the Marangoni convection. Phase transitions significantly affect the convective flow, changing the coefficient of surface tension. In this paper, the behavior of a thin film of an alcohol-containing solution when it is heated is analytically studied. The change in the temperature of the free surface together with the escape of the volatile component leads, as a rule, to two opposite effects with respect to the directionality of the surface tension gradient. It is shown that four time scales associated with the development of velocity, temperature and concentration fields, as well as the change in layer height, can be distinguished in the considered non-stationary problem of a film deformation. Depending on the initial thickness deformation of the film can both advance the development of the concentration field, and lag behind it. In the linear approximation formulas for the fields of the basic quantities, and also for the asymptotics of the film deformation process are obtained.

Keywords

• thermocapillary flow
• marangoni convection
• deformation of a liquid film.