Collaborative Research: Dynamics of Miscible Jets and Drops

1335632/1335666 PI：富勒/沈阳混合喷嘴和液滴的转化以及液滴的溶解是许多工艺流程中遇到的常见事件。了解瞬时界面张力的演变是至关重要的，而界面张力一直无法测量。这些挑战促使PIS小组最近展示了提取可混溶液体之间存在的非常微小和瞬时的界面张力的方法。这项合作研究旨在开发一系列补充实验来了解可混相液体对的流体动力学，这些液体对可以通过各种形式相互作用：可混相喷嘴、可混相悬浮液滴和可混相静止液滴。这些实验将得到与埃因霍温技术大学安德森教授合作的数值模拟的补充。这些多相流系统中的每一个导致的结果都与不相容的液体对所遇到的结果有质的不同。其具体目标是：(1)研究液滴和射流通过第二种可混溶液体的传输；(2)悬浮液滴在微流体环境中经历停滞点伸展流动；(3)可混相液体的固着液滴在基质液体中扩散和溶解；(4)可混相悬浮液滴、射流和固相液滴的扩散界面模拟。模拟的结果将与喷嘴和液滴中界面形状的实验测定相比较。混相液体对的动力学以前很少受到关注，但在许多物理过程中是核心的。可混溶材料的组合可以产生稳定、复杂的形态，这是不相容的混合物所不可能做到的。可混溶液体射流在放大生产难以加工的高取向纤维方面具有很大的优势。可混溶的固着液滴的溶解是多相流中的一个丰富的问题，它提供了与干燥液滴相似的有趣的类比，以及提取可混溶液体之间界面张力的测量的可能性。测量界面张力的微流体方法可以应用于其他物理问题，例如正在进行化学反应的系统，其中界面张力随时间变化。类似的方法也可以适用于包含不同类型的可混溶流体、液滴和生物分子。该项目将为研究生和本科生提供研究培训。在这个项目中开发的结果也将成为向高中生和本科生介绍流体力学和界面现象的绝佳教学工具。

1335632/1335666 PI: Fuller/ShenThe translation of miscible jets and drops, and the dissolution of drops are common events encountered in numerous technological processes. It is critical to understand the evolution of the transient interfacial tension, which has eluded measurement. These challenges motivated methods recently demonstrated by the PIs groups to extract very small and transient interfacial tensions existing between miscible liquids. This collaborative research aims to develop a series of complementary experiments to understand the fluid dynamics of miscible pairs of liquids, which can interact with one another through various formats: miscible jets, miscible suspended droplets, and miscible sessile drops. These experiments will be supplemented by numerical simulations in collaboration with Professor Anderson of Eindhoven Technical University. Each of these multiphase flow systems result in outcomes that are qualitatively different from those encountered by immiscible liquid pairs. The specific aims are: (1) studies of drop and jets translating through a second, miscible liquid; (2) suspended droplets of a miscible liquid experiencing stagnation point extensional flow in a microfluidic environment; (3) sessile drops of a miscible liquid spreading and dissolving within a matrix liquid; and (4) diffuse interface simulation of miscible pendant drops, jets and sessile drops. The results from the modeling will be compared against experimental determinations of the interfacial shapes in jets and drops.The dynamics of miscible liquid pairs has received little previous attention but are central to many physical processes. The combination of miscible materials can produce stable, intricate morphologies that are not possible with immiscible mixtures. Jets of miscible liquids can be used to great advantage in the scale-up production of highly oriented fibers that are otherwise difficult to process. The dissolution of miscible, sessile drops is a rich problem in multiphase flow that offers interesting analogies to desiccating drops along with the possibility of extracting measures of the interfacial tension between miscible liquids. The microfluidic approach to measuring interfacial tensions can be applied to other physical problems, such as systems undergoing chemical reactions, where the interfacial tension is changing with time. Similar approaches can also be adapted to incorporate different types of miscible fluids, drops, and biomolecules. The project will provide research training to graduate and undergraduate students. The results developed in this program will also make wonderful teaching tools for the introduction of fluid mechanics and interfacial phenomena to high school and undergraduate students.