The study of Marangoni Convection in Evaporating Droplets of Liquids and Colloidal Solutions

Numerical investigation of quasi-steady internal flows in an axially symmetrical evaporating sessile droplet was the major problem of current study. The fluid dynamics of an evaporating sessile drop, effects of the heat conduction in the droplet and substrate and diffusion of vapor in air have been taken into account jointly. The equations have been solved by the finite element method using ANSYS Fluent. We allow for influence of gravity on the droplet shape and concider the effect of droplet size. Temperature distributions and the corresponding quasistationary fluid flow structures are obtained for evaporating sessile droplets of 1-hexanol, 1-butanol and ethanol. The phase diagrams, containing information on the number and orientation of the vortices depending on the contact angle and the ratio of substrate to fluid thermal conductivities [1], are obtained. On the basis of these results we conclude that the Marangoni effect in an evaporating droplet may be controlled by various values of parameters.