标题： 蒸发纯、二元和三元液滴：热效应和轴对称性破坏 显示英文标题

标题： Evaporating pure, binary and ternary droplets: thermal effects and axial symmetry breaking

摘要： 希腊开胃酒欧佐（Ouzo）不仅以其特有的茴香风味而闻名，还因其在加入水后能够从透明的可混液体转变为乳白色的乳液的能力而著称。最近的研究表明，这种所谓的欧佐效应，即油微滴的自发乳化作用，也可以通过蒸发的欧佐液滴中乙醇的优先蒸发来引发，导致一个令人惊讶的丰富的干燥过程，包含多种相变 [H. Tan 等，Proc. Natl. Acad. Sci. USA 113(31) (2016) 8642]。由于接触线附近的蒸发增强，油滴的成核开始于边缘，从而形成环绕液滴的油环。此外，油滴通过快速的溶质马兰戈尼流在欧佐液滴中被输运。在本文中，我们通过逐步增加混合物的复杂性，从纯水经过二元水-乙醇混合物到三元欧佐混合物（水、乙醇和茴香油），更详细地研究了混合物液滴的蒸发。特别是对这些液滴进行了轴对称和全三维有限元方法模拟，以讨论由优先蒸发、蒸发冷却以及溶质和热马兰戈尼流相互作用驱动的液滴中的热效应和复杂流动。通过使用图像分析技术和微PIV测量，我们能够将数值预测的体积变化和速度场与实验数据进行比较。此外，还通过共聚焦显微镜研究了欧佐液滴。结果表明，油环主要由于聚并而出现。 显示英文摘要

摘要： The Greek aperitif Ouzo is not only famous for its specific anise-flavored taste, but also for its ability to turn from a transparent miscible liquid to a milky-white colored 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 [H. Tan et al., Proc. Natl. Acad. Sci. USA 113(31) (2016) 8642]. 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-PIV 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.