Experimental investigation of thermal structures in regular three-dimensional falling films
- 113 Downloads
Interfacial waves on the surface of a falling liquid film are known to modify heat and mass transfer. Under non-isothermal conditions, the wave topology is strongly influenced by the presence of thermocapillary (Marangoni) forces at the interface which leads to a destabilization of the film flow and potentially to critical film thinning. In this context, the present study investigates the evolution of the surface topology and the evolution of the surface temperature for the case of regularly excited solitary-type waves on a falling liquid film under the influence of a wall-side heat flux. Combining film thickness (chromatic confocal imaging) and surface temperature information (infrared thermography), interactions between hydrodynamics and thermocapillary forces are revealed. These include the formation of rivulets, film thinning and wave number doubling in spanwise direction. Distinct thermal structures on the films’ surface can be associated to characteristics of the surface topology.
KeywordsEuropean Physical Journal Special Topic Thermal Structure Wave Crest Infrared Thermography Residual Layer
Unable to display preview. Download preview PDF.
- 1.S.V. Alekseenko, V.E. Nakoryakov, B.G. Pokusaev, Wave Flow of Liquid Films (Begell House, 1994)Google Scholar
- 2.W. Boos, A. Thess, Phys. Fluids, 11 (1999)Google Scholar
- 4.G.F. Dietze, Flow separation in falling liquid films, Ph.D. thesis, RWTH Aachen, 2010Google Scholar
- 10.S. Kalliadasis, C. Ruyer-Quil, B. Scheid, M.G. Velarde, Falling Liquid Films (Springer London Dordrecht Heidelberg, New York, 2012)Google Scholar
- 11.V.V. Lel, Hydrodynamik und Wärmeübergang laminar-welliger Rieselfilme, Ph.D. thesis, RWTH Aachen, 2007Google Scholar
- 19.W. Rohlfs, H.D. Haustein, G.F. Dietze, R. Kneer, Proceedings of the 6th International Berlin Workshop – IBW3 on Transport Phenomena with Moving Boundaries, Nov. 24-25, 2011, Berlin, VDI Fortschritts-Bericht VDI Reihe 3, Verfahrenstechnik 929, Düsseldorf VDI-VerlagGoogle Scholar
- 23.D.W. Zhou, T. Gambaryan-Roisman, P. Stephan, J. Heat Trans. 33(2), 273 (2009)Google Scholar