CAREER: Inertial Two-Phase Gas-Liquid Droplet Microflows

1151091Hidrovo该项目旨在从根本上了解惯性气液两相液滴微流背后的主导物理，目标是开发能够同时处理微秒级时间和数十毫升/分钟吞吐量的新型微流控系统。该项目的变革性方面在于对高速惯性微流体和液滴微流动这一新兴领域提供了新的见解。这一认识将导致新一代芯片实验室(LOC)和微全分析系统(MTAS)的发展，具有前所未有的处理速度和处理能力。研究旨在解决(1)惯性、粘性和表面张力在液滴分离机制中的作用和相互作用，(2)绘制可能导致液滴产生的不同流型和转变图，以及(3)受限微通道环境中惯性液滴碰撞混合的动力学。为了实现这些目标，将开展研究工作，重点是利用新的光学诊断技术对快速液滴动力学和相互作用进行实验研究。具体地说，一个微流控液滴生成平台，可以控制和监测液体和气体的流动状况，将与高速显微镜系统耦合，以研究液滴的携带动力学。同样，一个微流体液滴对碰撞平台将被耦合到一个高速表观荧光显微镜系统，在该系统中，微分双荧光测量和mPIV将被用作揭示与惯性碰撞混合相关的快速动力学的工具。实验工作将通过对不同现象的一阶建模和全局力分析来补充。该项目的智力优势包括阐明惯性效应在受限气体载体微流中液滴脱离、夹带和碰撞混合中的作用。本研究中将要进行的测试结构和实验将为了解不同流动和边界条件对液滴形成和碰撞合并的影响提供独特的见解。将使用的微流体测试样品的设计和制造使得液滴相互作用的几何和流动条件可以被仔细地控制，从而允许更清楚地了解不同微观几何参数对夹带和碰撞合并过程的影响。这项工作的研究努力和成果将被整合到教育和推广活动中，这些活动将向未被充分代表的本科生和高中生介绍微尺度流动和传输领域。将推出创新的、多层次的、自我可持续的方案，旨在发展教学内容，同时提供研究培训。对个别学生的研究培训将通过暑期实习计划进行，旨在开发微流控和光学诊断实验室模块和演示。这些将分别在本科生实验班和几个外展项目中部署和引入。

1151091HidrovoThis project aims to fundamentally understand the governing physics behind inertial two-phase gas-liquid droplet microflows, with the objective of developing novel microfluidic systems capable of microsecond processing times and tens of mL/min throughputs, simultaneously. The transformative aspect of the project resides in providing new insights into the emerging field of high speed inertial microfluidics and droplet microflows in specific. This understanding will lead to the development of next generation Lab-on-a-Chip (LOC) and micro-Total Analysis Systems (mTAS) with processing speed and throughput capabilities not seen before.The research aims to address (1) the role and interplay between inertial, viscous and surface tension forces in the droplet detachment mechanism, (2) mapping of the different flow regimes and transitions that can lead to droplet generation, and (3) the dynamics of inertial droplet collision mixing in a confined microchannel environment. Towards these goals, research efforts will be put forward that focus on the experimental study of the fast droplet dynamics and interactions through the use of novel optical diagnostics techniques. In specific, a microfluidic droplet generation platform that allows control and monitoring of the liquid and gas flows conditions will be coupled to a high speed microscopy system to study the liquid droplet entrainment dynamics. Similarly, a microfluidic droplet pair collision platform will be coupled to a high speed epi-fluorescence microscopy system, where differential dual fluorescence measurements and mPIV will be used as tools to unravel the fast dynamics associated with inertial collision mixing. The experimental work will be complemented by first order modeling and global force analysis of the different phenomena.The intellectual merit of the project includes elucidating the role of inertial effects in the detachment, entrainment and collision mixing of liquid droplets in confined gas carrier microflows. The test structures and experiments to be carried out in this study will provide unique insight into the effects that different flow and boundary conditions have on droplet formation and collision coalescence. The microfluidic test samples to be used are designed and fabricated so that the geometry and flow conditions under which the droplets interact can be carefully controlled, allowing for a clearer understanding of the effects that different microscopic geometrical parameters have on the entrainment and collision coalescence processes.The research endeavors and outcomes from this work will be integrated into educational and outreach activities that will introduce the field of microscale flow and transport to underrepresented undergraduate engineering and high school students early in their career. Innovative multilayer, self-sustainable programs geared towards development of teaching content while providing research training, will be introduced. Research training of individual students will take place through summer internship programs aimed at developing microfluidic and optical diagnostics lab modules and demonstrations. These will in turn be deployed and introduced in an undergraduate experimental class and several outreach programs, respectively.