When a layer of volatile liquid is subject to a flow of inert gas, a non-uniform distribution of the evaporation rate is generated all along the interface. Being evaporation stronger at the inlet boundary of the layer, because of the maximal efficiency of the inert gas flow in removing vapor from the interface, a thermal gradient along the interface is generated. Two opposite mechanisms regulate the movement of the interface: the shear stress of the gas that entrains the interface in the direction of the flow and the thermo-capillary stress that forces the interface to move against the flow direction. Moreover, because of the overall cooling of the interface due to the evaporative process, a gradient normal to the interface is also created. It results in a potentially unstable situation that is strongly influenced by the flow rate of inert gas, the layer thickness and the liquid thermo-physical properties. The goal of the present work is to study numerically if and how the dynamic evolution of the liquid layer is driven by the above-mentioned mechanisms. The main results concern the evaluation of the influence of the thermal instability patterns, eventually generated by the concurrent action of non-uniform evaporation and thermo-capillary motion, on the heat transfer at the bottom liquid. The distribution of temperature and velocity in the gas and liquid bulk phase for different mass flow rate of inert gas has also been of interest.

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