UNS: Employing hydrodynamic lift and particle trajectory ratcheting to achieve sieve-free separations based on size and shape in cross-flow filtration

1505795（Koch）提出的研究重点是研究悬浮液横流过滤过程中发生的粒子输运现象。除了发展对这些现象的基本理解外，目标是帮助开发所谓的无筛过滤系统。虽然所提出的工作是高度基础的，但工程应用是其动力。本文拟对横流中颗粒分离进行理论/数值/实验相结合的研究。这项研究的动机是改进横流过滤的实践，横流过滤是一种从流体和较小尺寸的颗粒中分离颗粒（包括细胞或大分子）的高通量方法。在常规操作中，分离是通过筛选具有小孔径的膜来完成的。PI认为，使用颗粒流体动力传输过程而不是膜排斥来完成分离的操作，将具有减少膜污染和提高分离选择性的优点，专家组也同意这一点值得探索。由于横流过滤具有较高的剪切速率，惯性升力可以使颗粒远离粗的非过筛膜。此外，还将研究一种新的无筛分离机制，该机制基于颗粒在膜粗糙表面的棘轮运动，这是由于颗粒与膜的体积相互作用被排除在外。目标是开发一种基于升力的交叉流预测模型，允许基于形状和尺寸的分离，并确定颗粒可以保留的最大过滤通量和颗粒浓度。这种机制可以导致纳米颗粒或蛋白质的无筛分离，因为它们太小而无法基于流体动力升力分离。将对开发的模型进行测试，并通过在Couette细胞过滤器中对尺寸和形状控制良好的微颗粒和纳米颗粒进行分离的实验测量来证明无筛过滤的可靠性。除了研究生教育外，还计划向K-12学生提供服务，并在当地儿童博物馆和伊萨卡科学中心的活动中进行实验演示。

1505795(Koch)The focus of the proposed research is to study particle transport phenomena that occur during cross-flow filtration of suspensions. In addition to development of fundamental understanding of these phenomena, the objective is to aid the development of a so-called sieve-free filtration system. While the proposed work is highly fundamental, engineering applications are its motivation.This is a proposal to conduct a combined theoretical/numerical/experimental study of particle separation in crossflow. The motivation for this study is to improve practices in cross-flow filtration - a high throughput method of separating particles (including cells or macromolecules) from a fluid and from smaller sized particles. In conventional operation, the separation is accomplished by sieving through a membrane with a small pore size. The PI argues, and the panel agreed that this is worth exploring, that an operation in which the separation is accomplished using particulate hydrodynamic transport processes rather than membrane exclusion would have the advantages of decreasing membrane fouling and improving the selectivity of the separation. Because of the high shear rates accessible in cross-flow filtration, inertial lift can keep the particles away from the coarse non-sieving membrane. In addition, a new sieve-free separation mechanism based on the ratcheting of particle trajectories at the rough surface of the membrane due to excluded volume interactions of the particle with the membrane will be investigated. The goal is to develop a predictive model for lift-based cross-flow, allowing separation based on shape as well as size and identifying the maximum filtration flux and particle concentration at which particles can be retained. This mechanism can lead to sieve-free separations of nanoparticles or proteins which are too small to separate based on hydrodynamic lift. The models developed will be tested and the reliability of sieve-free filtration demonstrated by experimental measurements of separation of micro- and nano-particles of well controlled size and shape in a Couette cell filter. In addition to graduate education, plans to reach out to K-12 students and by an experimental demonstration to be used in activities at the local children's museum and the Ithaca Science Center are laid out.