Transient rise velocity and mass transfer of a single drop with interfacial instabilities—Numerical investigations

Full 3D-simulations of transient interfacial mass transfer accompanied by Marangoni convection at a single spherical droplet in a quiescent liquid were performed in a moving reference coordinate system. The flow and concentration field are solved simultaneously, coupled via the additional Marangoni stress generated by concentration gradients at the interface. Fluid dynamics and mass transfer are investigated in the Marangoni convection dominated toluene/acetone/water system. The numerical results are qualitatively and quantitatively compared with own experimental results. The simulation results reveal that mass transfer is always enhanced—compared to calculations where no Marangoni convection appears—independently from the initial solute concentration. The enhancement factor of mass transfer ranges between 2 and 3.