CAREER: Interrogating and Exploiting the Hydrodynamics of Concentrated Emulsions for Droplet Microfluidics

本职业项目研究微通道流动中浓乳剂的流体动力学。通常在这些流动中，液滴变得紧密，它们可以相互结合或分离。在微流控系统的许多应用中，液滴中含有化学试剂或生物样品，因此跟踪液滴通过微流控装置的单个运动是必要的。如果液滴重新排列顺序或分裂，追踪它们就变得不可能了。该项目将确定液滴保持其相对空间排列的流动状态，即使当流体将液滴带过包含其横截面形状变化的微通道时。该项目的结果将对设计微流体系统的实践者在工程、生物科学和医学等领域的各种应用有帮助。此外，研究结果将用于开发工程本科生的新课程，以及为K-12学生开发演示模块和视频演示。该项目将研究浓缩乳剂在流过具有限制几何形状的微通道时的运动。初步结果显示了一种有趣的流动状态，当流动方向改变时，液滴在包含收缩的通道中移动的空间排列是完全可逆的，而另一种状态导致液滴随机破裂。该提案的目标是参数化表征这些制度，确定液滴破裂的原因，并为需要液滴通过微流体装置移动的设备生成设计规则，以保持液滴通过整个装置的精确顺序。

CBET - 1454542PI: Sindy Tang, Stanford UniversityThis CAREER project addresses the hydrodynamics of concentrated emulsions in microchannel flows. Typically in these flows, the droplets become closely packed, and they can coalesce with each other or break apart. In many applications of microfluidic systems, the drops contain chemical reagents or biological samples, and it is imperative to track the individual motion of drops through the microfluidic device. If the drops rearrange their order or breakup, tracking them becomes impossible. This project will identify flow regimes in which drops retain their relative spatial arrangements even when the flow takes the drops through microchannels that contain changes in their cross-sectional shapes. The results of the project will be useful to practitioners who design microfluidic systems for a variety of applications in engineering, biological sciences, and medicine. In addition, results from the research will be used in the development of a new course for engineering undergraduates as well as in the development of demonstration modules and video presentations for K-12 students.The project will examine the motion of concentrated emulsions in flow through microchannels with confining geometries. Preliminary results demonstrate an interesting flow regime where the spatial arrangement of drops that move through a channel containing a contraction is exactly reversible when the direction of the flow is changed and another regime that results in a stochastic breakup of drops. The goals of the proposal are to characterize these regimes parametrically, identify the cause of drop breakup, and to generate design rules for devices that require drops to move through microfluidic devices maintaining precisely the sequential order of drops through the entire device.