Marangoni convection induced by simultaneous mass and heat transfer during evaporation of n-heptane/ether binary liquid mixture

The Marangoni convection induced by simultaneous temperature and concentration gradient during the evaporation process of the binary liquid mixture was observed by means of the optical shadowgraph technique, and its morphology was presented. In order to investigate effects of temperature and concentration gradient on the Marangoni convection, a transient numerical computation was developed and conducted by combining the Volume of Fluid (VOF) numerical method with the continuum surface tension (CSF) method. The details of the local velocity field and concentration distribution of the Marangoni convection was revealed by the simulation, and the reference time when the Marangoni convection took effect to enhance the mass transfer coefficient was acquired. Meanwhile, the Marangoni convection induced by either the temperature gradient or the concentration gradient in this evaporation process was respectively investigated numerically to survey influence of the thermal effect accompanying in mass transfer on the Marangoni convection.