Thermocapillary rupture and contact line dynamics in the heated liquid layers

The experimental study of the rupture of a horizontal liquid layer placed on a stainless-steel substrate non-uniformly heated from below was conducted. Deformation profiles in the liquid film were measured using the confocal Micro-Epsilon sensor. Propagation of a dry spot over the substrate surface was studied using an optical schlieren system coupled with a high-speed camera. The initial thickness of the liquid film varied from 300 to 1100 µm. It was found that with an increase in the liquid layer thickness, the threshold substrate temperature for rupture increases. At the initial stage of film rupture, the contact line velocity has a maximum increasing with the initial film thickness.