Evaporating pure, binary and ternary droplets: thermal effects and axial symmetry breaking
| Autor: | Michel Versluis, Xuehua Zhang, Pengyu Lv, Detlef Lohse, Huanshu Tan, Jgm Hans Kuerten, Christian Diddens |
|---|---|
| Přispěvatelé: | Energy Technology, Power & Flow, Group Kuerten, Physics of Fluids |
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Materials science
Marangoni convection Nucleation FOS: Physical sciences Thermodynamics 02 engineering and technology 01 natural sciences 010305 fluids & plasmas Physics::Fluid Dynamics Ouzo effect 0103 physical sciences Marangoni effect Mechanical Engineering Drop (liquid) Fluid Dynamics (physics.flu-dyn) Physics - Fluid Dynamics 021001 nanoscience & nanotechnology Condensed Matter Physics Condensation/evaporation Mechanics of Materials Oil droplet Emulsion 2023 OA procedure Drops 0210 nano-technology Ternary operation Evaporative cooler |
| Zdroj: | Journal of Fluid Mechanics, 823, 470-497. Cambridge University Press Journal of fluid mechanics, 823, 470-497. Cambridge University Press |
| ISSN: | 0022-1120 |
| DOI: | 10.1017/jfm.2017.312 |
| Popis: | The Greek aperitif Ouzo is not only famous for its specific anise-flavoured taste, but also for its ability to turn from a transparent miscible liquid to a milky-white coloured emulsion when water is added. Recently, it has been shown that this so-called Ouzo effect, i.e. the spontaneous emulsification of oil microdroplets, can also be triggered by the preferential evaporation of ethanol in an evaporating sessile Ouzo drop, leading to an amazingly rich drying process with multiple phase transitions (Tan et al., Proc. Natl Acad. Sci. USA, vol. 113 (31), 2016, pp. 8642–8647). Due to the enhanced evaporation near the contact line, the nucleation of oil droplets starts at the rim which results in an oil ring encircling the drop. Furthermore, the oil droplets are advected through the Ouzo drop by a fast solutal Marangoni flow. In this article, we investigate the evaporation of mixture droplets in more detail, by successively increasing the mixture complexity from pure water over a binary water–ethanol mixture to the ternary Ouzo mixture (water, ethanol and anise oil). In particular, axisymmetric and full three-dimensional finite element method simulations have been performed on these droplets to discuss thermal effects and the complicated flow in the droplet driven by an interplay of preferential evaporation, evaporative cooling and solutal and thermal Marangoni flow. By using image analysis techniques and micro-particle-image-velocimetry measurements, we are able to compare the numerically predicted volume evolutions and velocity fields with experimental data. The Ouzo droplet is furthermore investigated by confocal microscopy. It is shown that the oil ring predominantly emerges due to coalescence. |
| Databáze: | OpenAIRE |
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