Experimental investigation of 3-dimensional wavy liquid films under the coupled influence of thermo-capillary and electrostatic forces

• Published in: The European physical journal. ST, Special topics Special topics, 2013-03, Vol.219 (1), p.111-119
• Main Authors: Rohlfs, Wilko, Dietze, Georg F., Haustein, Herman D., Kneer, Reinhold
• Format: Article
• Language: English
• Subjects: Atomic; Classical and Continuum Physics; Condensed Matter Physics; Condensed matter: structure, mechanical and thermal properties; Engineering Sciences; Exact sciences and technology; Liquid thin films; Materials Science; Measurement Science and Instrumentation; Molecular; Optical and Plasma Physics; Physics; Physics and Astronomy; Reactive fluid environment; Regular Article; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 1951-6355; 1951-6401
• DOI: 10.1140/epjst/e2013-01786-2

Three-dimensional interfacial waves developing on the free surface of falling liquid films are known to intensify heat and mass transfer. In this context, the present paper studies the effect of electrostatic as well as of thermo-capillary forces on a falling film of a dielectric liquid. Therefore, measurements of the local film thickness using a confocal chromatic imaging method were performed under isothermal and heated conditions. The experimental results show that both forces destabilize the flow. It is found, that the application of an additional electric field under heating conditions enhances the generation of rivulets, thereby reducing the overall heat transfer coefficient.