Collaborative Research: Dynamics of Miscible Jets and Drops

混相射流和液滴的转化和液滴的溶解是许多工艺过程中经常遇到的事件。了解瞬态界面张力的演变是至关重要的，这是无法测量的。这些挑战激发了pi小组最近展示的方法，以提取存在于混相液体之间的非常小的瞬态界面张力。这项合作研究旨在开发一系列互补实验，以了解可通过各种形式相互作用的混相液体对的流体动力学：混相射流，混相悬浮液滴和混相无底液滴。这些实验将与埃因霍温工业大学的安德森教授合作，辅以数值模拟。这些多相流系统的每一个结果都与不混相液体对所遇到的结果有质的不同。具体目标是：(1)研究水滴和射流通过第二种可混溶液体的转化；(2)在微流体环境中，混相液体的悬浮液滴经历驻点伸展流动；（三）可混溶液体的固滴在基质液体中扩散和溶解；(4)悬垂液滴、射流和无底液滴混相扩散界面模拟。模拟结果将与射流和液滴界面形状的实验测定结果进行比较。可混相液体对的动力学以前很少受到关注，但却是许多物理过程的核心。混相材料的组合可以产生稳定的，复杂的形态，这是不可能的非混相混合物。可混相液体射流在高取向纤维的大规模生产中具有很大的优势，否则难以加工。在多相流中，可混溶的无底液滴的溶解是一个丰富的问题，它提供了与干燥液滴有趣的类比，并提供了可混溶液体之间的界面张力的提取方法的可能性。测量界面张力的微流体方法可以应用于其他物理问题，例如发生化学反应的系统，其中界面张力随时间变化。类似的方法也可以适用于不同类型的混溶液体、滴剂和生物分子。该项目将为研究生和本科生提供研究培训。本项目的研究成果也将为高中和本科学生介绍流体力学和界面现象提供很好的教学工具。

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.