Collaborative Research: Experimental and Computational Studies of Flow and Clogging of Deformable Particles under Confinement

合作研究：约束下可变形颗粒流动和堵塞的实验和计算研究

• 批准号: 2002782
• 负责人: Corey O'Hern
• 金额: $ 20万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-15 至 2023-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2002782&HistoricalAwards=false
• 关键词: Collaborative; Research; Experimental; Computational; Studies

Squishy, deformable particles play an important role in many fields of science and engineering, from the biological cells to droplets of fatty oils in water that make up emulsions like mayonnaise, peanut butter, and milk. Microfluidic devices with tiny channels of varying widths are used to process mixtures of deformable particles and fluids and to manipulate DNA molecules. However, microfluidic devices frequently clog near constrictions, which is expensive since the device must be replaced when this occurs. Clogging has been studied extensively for rigid particles, like grains flowing out of a silo, but clogging of deformable particles is less well understood. In particular, it is unclear how particle deformability and stickiness or cohesion affects clogging. For example, will deformable and cohesive particles change shape and flow past each other at constrictions, or will they form arches and clog the system? This project combines experiments of emulsion droplets flowed through microfluidic devices with novel computer simulations of deformable particles to understand how they clog. This work will aid in future designs of critical microfluidic devices involved in industrial processing, filtration, and analysis of biological samples of cell-fluid mixtures.Flow-induced jamming, or clogging, is observed across a wide range of systems, from flows of granular materials in silos to flows of blood cells through veins. Clogging is well studied in the case of hard, frictional grains, but is poorly understood when particles are deformable and cohesive. This project employs experiments of suspensions of emulsion droplets with tunable deformability and adhesion flowed through microfluidic devices, along with novel simulations of flows of explicitly deformable particles designed to model emulsion droplets. The combined experimental-computational approach can disentangle the effects of deformability, particle mechanical response, and adhesion on clogging probability. One key focus is the role of particle rearrangements during clogs in unjamming the suspensions. During clogs of granular materials, particles are static and clogs have long lifetimes. However, if particles are deformable, particle shape relaxation and stress redistribution in a clogged suspension can lead to intermittent clog release and avalanching. Additionally, this project will investigate how the Beverloo Law, which describes how flow rate changes with constriction width, changes in the case of deformable and adhesive particles. The combination of computational and experimental studies will aid the development of a comprehensive theoretical framework to predict when a clog will form given the particle properties, flow rate, and constriction width. With the increased use of microfluidic devices to analyze suspensions of colloidal particles and cells, a predictive framework for clogging based on single-particle properties like deformability, elasticity and adhesion is required to design the next generation of efficient high-throughput microfluidic devices.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

柔软的可变形颗粒在许多科学和工程领域都起着重要作用，从生物细胞到水中的脂肪油液滴，这些脂肪油构成了蛋黄酱，花生酱和牛奶等乳液。 带有不同宽度的微小通道的微流体设备用于处理可变形颗粒和流体的混合物，并操纵DNA分子。但是，微流体设备经常堵塞接近收缩，这很昂贵，因为在发生这种情况时必须更换设备。已经对刚性颗粒进行了广泛的研究，例如从筒仓中流出的谷物，但是对可变形颗粒的堵塞的理解较少。特别是，目前尚不清楚粒子的可变形性和粘性或凝聚力如何影响堵塞。例如，可变形和凝聚力颗粒会在约束时互相改变形状和流动，还是会形成拱门并堵塞系统？该项目结合了流经微流体设备的乳液液滴的实验，以及可变形颗粒的新计算机模拟，以了解它们的堵塞方式。这项工作将有助于对未来的设计，包括工业加工，过滤涉及的关键微流体设备，并分析细胞 - 流体混合物的生物样品。流量引起的干扰或堵塞，从各种系统中观察到，从细胞流到血细胞流到血细胞流到血细胞的流量。在坚硬的摩擦晶粒的情况下，对堵塞进行了充分的研究，但是当颗粒可变形和凝聚力时，人们对堵塞的理解很少。该项目采用了具有可调节性和粘附的乳液液滴悬浮液的实验，并流过微流体设备，以及针对模拟乳液液滴建模的明显变形颗粒流的新模拟。合并的实验计算方法可以使变形，粒子机械响应和粘附对堵塞概率的影响脱离。一个重点是堵塞过程中粒子重排的作用在解开悬浮液中。在颗粒材料的堵塞期间，颗粒是静态的，堵塞的寿命很长。但是，如果颗粒可变形，则在堵塞的悬浮液中的颗粒形状松弛和应力再分配可能会导致间歇性的堵塞释放和雪崩。此外，该项目将调查贝弗鲁法律如何描述流速如何随收缩宽度而变化，这是可变形和粘合剂颗粒的情况的变化。计算和实验研究的结合将有助于开发一个综合理论框架，以预测何时在粒子特性，流速和收缩宽度的情况下形成堵塞。随着微流体设备的增加使用来分析胶体颗粒和细胞的悬浮液，需要基于单粒子特性（例如变形，弹性和粘附）来设计堵塞的预测框架，以设计下一代高效的高直发设备，以反映NSF的Infortional Indertion deem dee eyter te eymer te eym te eym eyter of dee eyter of dee eyter of deem a奖，这是必需的。影响审查标准。

项目成果

Bridging particle deformability and collective response in soft solids

桥接软固体中的颗粒变形性和集体响应

• DOI: 10.1103/physrevmaterials.5.055605
• 发表时间: 2021
• 期刊: Physical Review Materials
• 影响因子: 3.4
• 作者: Treado, John D.;Wang, Dong;Boromand, Arman;Murrell, Michael P.;Shattuck, Mark D.;O'Hern, Corey S.
• 通讯作者: O'Hern, Corey S.

Shear response of granular packings compressed above jamming onset

堵塞开始时压缩颗粒填料的剪切响应

• DOI: 10.1103/physreve.103.022902
• 发表时间: 2021
• 期刊: Physical Review E
• 影响因子: 2.4
• 作者: Wang, Philip;Zhang, Shiyun;Tuckman, Philip;Ouellette, Nicholas T.;Shattuck, Mark D.;O'Hern, Corey S.
• 通讯作者: O'Hern, Corey S.