Two-layer fluid flows with evaporation at the thermocapillary interface have been studied on the basis of the partially invariant solution of the convection equations. The modeling of the 3D fluid flows has been performed in an infinite channel of the rectangular cross section without assuming the axis-symmetrical character of the flows. The fluid flow patterns are determined by various thermal, mechanical and structural effects. Numerical investigations have been carried out for the liquid–gas system like ethanol–nitrogen and HFE-7100–nitrogen under terrestrial conditions. The solution takes into account the direct and inverse thermodiffusion effects in the gas–vapor phase. Influence of the applied thermal load, thickness of the liquid layer and thermophysical properties of the working media on topology and character of the flows is studied. It allows one to describe the formation of thermocapillary rolls and symmetrical multi-vortex structures in the systems with heat transfer liquids like the ethanol or HFE-7100. The appearance of the thermal and solutal shafts, and the near-wall condensation effects observed in real experiments are predicted by the solution.
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