Thermocapillary flow in evaporating thin liquid films with long-wave evolution model

The thermocapillary convection is induced along a liquid-vapor interface due to surface tension gradient which is temperature dependent. The impact of thermocapillary effect on the thermal behavior of an evaporating thin liquid film is investigated in this work. By employing the long-wave evolution model, a mathematical model based on first principles for fluid flow and heat transfer is derived for the interface shapes that govern the thickness of the evaporating thin film. The two-dimensional information of the liquid temperature which is a prerequisite for the incorporation of the thermocapillary effect can be obtained. The analysis provides a well-defined exposition of the significance of such effect in thin-film evaporation, scrutinizing the changes entailed in the heat transfer characteristics. The evaporation rate is overrated when the thermocapillary effect is neglected and the overestimate increases with increasing excess temperature. This study reveals the conditions under which the thermocapillary effect is significant and should not be neglected in the heat transfer analysis of an evaporating thin film.