Studying the Dynamics of Breakdown of Thin Horizontal Liquid Layers with Local Heating

Abstract

Abstract. Experimental study of liquid layers breakdown when heated locally from the substrate side was made. Water and ethanol were used as working liquids with a layer thickness of 300 μm. Basic steps of the breakdown process were found and mean velocities of the dry spot formation were determined; the values are 0.06 mm/sec for ethanol and 5.15 mm/sec for water. The formation of residual layer over the hot-spot before the breakdown has been found for both liquids. The creation of a droplet cluster near the heating region is observed when using water as a working fluid. It was shown that evaporation is one of the general factors influencing the process of layer breakdown and dry spot formation as well as thermocapillary effect.

Breakdown dynamics of a horizontal evaporating liquid layer when heated locally

“…It was found out that for both working liquids the layer breakdown occurs according to one scenario [7,14,15]. First, a thermocapillary deformation of the layer above the point heating area appears (Fig.…”

“…2e. It should be noted that local heating of the water layer is followed by the formation of a droplet cluster [6,14,16] above the heating area and the breakdown takes place at a distance of about 1 mm from the substrate center. When using ethanol as a working liquid residual layer formation and rupture occur directly above the heating element in the center of the substrate.…”