Abstract
Thermocapillary convection in a thin liquid film inside a micro-slot with structured walls kept at different temperatures is studied. The liquid film is wetting the substrate wall and is separated from the cover wall by a gas layer. If the slot walls are structured, the temperature at the liquid–gas interface is non-uniform. The temperature variation induces thermocapillary stresses which bring the liquid into motion and lead to the interface deformation. We investigate the film flow inside the micro-slot, the heat transfer, the liquid–gas interface deformations and the film stability in the framework of the long-wave theory. We show that the amplitude of the interface deformation increases with increasing of the wall structure period. We demonstrate that the structured walls lead to the heat transfer enhancement, which effect is for the studied range of parameters stronger if the cover wall is structured. We also show that the wall structure enhances the long-wave Marangoni instability. The destabilizing effect of the substrate structure is stronger than that of the cover wall structure.
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The authors wish to acknowledge the support of the German Science Foundation, DFG, through the Emmy Noether Program.
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This work has been originally presented at the 3rd International Conference on Microchannels and Minichannels, 13–15 June 2005, Toronto, Canada.
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Gambaryan-Roisman, T., Stephan, P. Thermocapillary convection and interface deformation in a liquid film within a micro-slot with structured walls. Microfluid Nanofluid 3, 207–215 (2007). https://doi.org/10.1007/s10404-006-0118-3
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DOI: https://doi.org/10.1007/s10404-006-0118-3