Numerical Simulation of Thermocapillary Convection with Evaporation Induced by Boundary Heating

Abstract

The dynamics of a bilayer system filling a rectangular cuvette subjected to external heating is studied. The influence of two types of thermal exposure on the flow pattern and on the dynamic contact angle is analyzed. In particular, the cases of local heating from below and distributed thermal load from the lateral walls are considered. The simulation is carried out within the frame of a two-sided evaporative convection model based on the Boussinesq approximation. A benzine-air system is considered as reference system. The variation in time of the contact angle is described for both heating modes. Under lateral heating, near-wall boundary layers emerge together with strong convection, whereas the local thermal load from the lower wall results in the formation of multicellular motion in the entire volume of the fluids and the appearance of transition regimes followed by a steady-state mode. The results of the present study can aid the design of equipment for thermal coating or drying and the development of methods for the formation of patterns with required structure and morphology.