Evaporating binary droplets: significant impact of natural convection below the millimeter scale

ORAL

Abstract

While the evaporation of pure sessile droplets is well understood, the situation drastically changes when the droplet composition is constituted by a mixture of different liquids, as e.g. in typical applications like inkjet printing.
Due to different volatilities of the components, solutal gradients are induced, leading to solutal Marangoni flow and natural convection.
Remarkably, even for droplets below the millimeter scale, natural convection can dominate the Marangoni flow and decisively determine the direction of the flow inside the droplet.

On the basis of finite element simulations and experiments, we investigate the possible flow types. Finally, we are able to predict the flow in the droplets by phase-diagrams in terms of the Rayleigh and Marangoni numbers.

*This work is part of an Industrial Partnership Programme (IPP) of the Netherlands Organization for Scientific Research (NWO). This research programme is co-financed by Océ-Technologies B.V., University of Twente and Eindhoven University of Technology.

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Presenters

  • Christian Diddens

    • Univ of Twente
    • University of Twente, Eindhoven University of Technology

Authors

  • Christian Diddens

    • Univ of Twente
    • University of Twente, Eindhoven University of Technology

  • Yaxing Li

    • Univ of Twente

  • Herman Wijshoff

    • Océ Technologies B.V., The Netherlands, Eindhoven University of Technology, The Netherlands
    • Océ Technologies B.V.
    • Océ-Technologies B.V.

  • Michel Versluis

    • Physics of Fluids group, MESA+ Institute for Nanotechnology, TechMed Centre, University of Twente
    • Univ of Twente
    • University of Twente
    • University Twente

  • Detlef Lohse

    • University of Twente
    • Physics of Fluids and Max Planck Center for Complex Fluids Dynamics, University of Twente, Enschede, The Netherlands
    • Univ of Twente
    • Univ of Twente, Max Plank Institute for Dynamics and Self-Organization
    • Twente Tech Univ
    • University of Twente, Max Planck Center for complex fluid dynamics