Influence of the boundary thermal regime on characteristics of bilayer flows under diffusive evaporation

The characteristics of combined flows of evaporating liquid and laminar gas flow in a flat horizontal channel are studied based on the exact partially invariant solution of thermoconcentration convection equations. The influence of the liquid layer thickness and the conditions for the temperature function on the upper wall of the channel on the rate of evaporation caused by gas pumping is investigated. The exact solution is verified by comparison with experimental data. The linear stability of the exact solutions is studied. It is established that regardless of the type of boundary thermal regime, the system always experiences oscillatory instability in the in the form of cellular convection. Thermal insulation of the upper wall does not lead to a change in the structure of the most dangerous perturbations, slightly destabilizes the flow in the case of long-wave perturbations, and has a stabilizing effect in the case of short-wave perturbations.