Fundamentals of Viscous Withdrawal, Flow-Focusing & Light-Driven Jetting

建议编号：CBET-0730629首席研究员：张温迪·W机构：芝加哥大学粘性抽提、流动聚焦和光驱动喷射的基本原理新的工程工艺可以准确和快速地处理少量液体。这种技术使纹理控制在微米到亚微米级的新材料成为可能。理论/数值分析将阐明整体流动和界面变形之间的相互作用。焦点将集中在三个例子问题上：粘性夹带、细胞包裹和光诱导喷射。这三个都有直接的技术相关性。粘性液体的夹带可以被操纵，以产生细小、稳定的微米大小的喷嘴。这是制造纤维和电线的关键一步。细小的喷嘴还可以均匀地覆盖不规则形状的固体颗粒。特别是，它目前包裹了产生胰岛素的胰岛，以努力开发一种治疗I型糖尿病的移植疗法。光诱导喷射提供了一种完全利用激光光束产生和传输少量液体的方法，而不需要预制的微通道。PI将在一个共同的框架内分析这些问题，描述粘性流动和表面变形之间的相互作用。在前人工作的基础上，成功地对汇聚流动产生的界面变形进行建模，将有助于开发简单、渐近的过程模型，以及用于与实验进行定量比较的数值模型。更广泛的影响包括对动力学进行量化分析，以确定液体衬里管道中上升的气泡所获得的速度，这有助于开发用于呼吸道关闭的医疗方法，以及目前开发的微流体设备。这一分析结果可能与电纺复合纤维的形成、微流体通道中通过流动聚焦制造液滴、胶囊和光子带隙材料有关。这项研究还将在几个不同的层面上纳入科学教育。对模拟结果的分析，特别是模拟结果与实验测量之间的比较，将是芝加哥大学物理系赞助的夏季本科生/高中生研究计划的一部分。这项研究提出的一些更广泛的问题，特别是基本流体动力学与生物医学工程和纳米技术中的技术挑战之间的联系，将在流体动力学的研究生和本科生课程中进行探索。

PROPOSAL NO.: CBET-0730629 PRINCIPAL INVESTIGATOR: ZHANG, WENDY W. INSTITUTION: UNIVERSITY OF CHICAGO FUNDAMENTALS OF VISCOUS WITHDRAWAL, FLOW-FOCUSING & LIGHT-DRIVEN JETTINGNew engineering processes can manipulate small amounts of liquid with accuracy and speed. Such techniques make possible new materials whose textures are controlled on micron to sub-micron scales. A theoretical/numerical analysis will elucidate the interaction between bulk flow and interface deformation. Focus will be on three example problems: viscous entrainment, cell encapsulation and light-induced jetting. All three have direct technological relevance. The entrainment of a viscous liquid can be manipulated to create thin, stable micron-sized spouts. This is a crucial step in the manufacture of fibers and wires. Thin spouts can also coat irregularly-shaped solid particles uniformly. In particular, it currently encapsulates insulin-producing Islets in an effort to develop a transplant therapy for type I diabetes. Light-induced jetting offers a way to produce and transport small amounts of liquid using entirely light from a laser beam, without the need of pre-fabricated microchannels. The PI will analyze these questions within a common framework characterizing the interaction between viscous flow and surface deformation. Building on prior work successfully modeling the interface deformation produced by a converging flow will help develop simple, asymptotic models for the processes and also numerical models for quantitative comparisons to experiments. Broader impacts include quantitative analyses on the dynamics to determine the speed attained by a rising bubble in a liquid-lined tube has been instrumental in the development of medical treatments for airway closure, and in current development of microfluidic devices. Results obtained from this analysis are likely to be relevant to formation of compound fibers in electrical spinning, the manufacture of droplets, capsules and photonic band gap materials via flow-focusing in microfluidic channels. This research will also be incorporated into science education on several different levels. The analysis of simulation results, in particular the comparison between the simulation results and the experimental measurements, will be part of the summer undergraduate/high-school student research program sponsored by the Physics department at the University of Chicago. Some of the broader issues raised by this research, in particular the connection between fundamental fluid dynamics and technological challenges in bio-medical engineering and nanotechnology, will be explored in the graduate and undergraduate courses on fluid dynamics.