Investigation of disruption dynamics of the horizontal liquid layer with spot heating from the substrate side

Disruption of thin (0.3–0.7 mm) horizontal layers of liquid (ethanol) was experimentally investigated during local heating with the substrate side at a heater diameter of 1.6 mm. The influence of the liquid layer thickness and the heating intensity on rupture dynamics was investigated. Visualization and inspection of the liquid layer were realized using the schlieren and shadow methods. General steps of the disruption are determined and the average formation rate of the dry spot is measured, which is 0.2–4 mm/s and increases with increasing of both the layer thickness and the heat flux. It is shown that one of the general factors that affect the rupture dynamics of the liquid layer and the formation of the dry spot in the area of local heating apart from the thermocapillary effect is evaporation.