Experimental investigation of 3-dimensional wavy liquid films under the coupled influence of thermo-capillary and electrostatic forces
1 Institute of Heat and Mass Transfer, RWTH Aachen University, Eilfschornsteinstrasse 18, 52064 Aachen, Germany
2 DAAD Fellow at Laboratoire FAST – UMR CNRS 7608, Université Pierre et Marie Curie, 91405 Orsay, France
a e-mail: firstname.lastname@example.org
Revised: 18 January 2013
Published online: 19 March 2013
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.
© EDP Sciences, Springer-Verlag, 2013