A Novel Particulate Separation Method

实验研究了自由悬浮粒子在毛细管分叉处的低雷诺数运动。分叉是一个管子分裂成两个管子的点。当颗粒悬浮液流过分支时，下游分支之间颗粒的分配不同于分支之间总体积（颗粒+悬浮液）的分配。这种差异是由于颗粒与分岔壁之间的流体动力相互作用以及颗粒从分岔壁附近的薄层中排除的结果。我们将研究这一原理，目的是设计一种从流体中分离颗粒的装置。粒子轨迹将通过实验测量，分岔几何形状、粒子大小和粒子体积分数的影响将被确定。实验结果将与基于质量和动量守恒的数值模型相结合，预测颗粒在通道网络中的运动和通量，并为分离装置的合理设计建立框架。许多具有重要生物和技术意义的制造过程都涉及固体颗粒在粘性液体中的悬浮液。将自由悬浮的颗粒从周围的液体中分离出来可能会带来重大的技术挑战，特别是当颗粒在悬浮介质中几乎是中性浮力的情况下。本项目将探索颗粒悬浮液在分支管中流动时的运动，并将利用流动的某些特征来设计一种新的颗粒分离方法。与传统方法（如膜基分离）相比，该工艺具有显著的潜在优势。该研究的目标是设计一种连续的、分阶段的分离过程，该过程几乎不需要维护或控制，对温度和压力等环境条件相对不敏感，并且不需要清洗或处理过滤元件。

The low Reynolds number motion of freely-suspended particles in bifurcations of capillary tubes will be studied experimentally. A bifurcation is a point where a tube splits to form two tubes. When a suspension of particles flows through a bifurcation, the partitioning of particles between the downstream branches differs from the partitioning of total volume (particles + suspending fluid) between the branches. The difference results from a combination of hydrodynamic interactions between the particles and the bifurcation wall and the exclusion of particles from a thin layer near the walls. This principle will be investigated with the aim of designing a device to separate particles from fluid. Particle trajectories will be measured experimentally, and the effects of bifurcation geometry, particle size, and particle volume fraction will be determined. Experimental results will be combined with numerical models based on mass and momentum conservation to predict the motion and flux of particles in networks of channels and build a framework for the rational design of a separation device.Many manufacturing processes of biological and technological importance involve suspensions of solid particles in a viscous liquid. Separating freely-suspended particles from the surrounding liquid can pose significant technical challenges, especially in cases where the particles are nearly neutrally buoyant in the suspending medium. This project will explore the motion of particulate suspensions as they flow through branching tubes, and will use certain characteristics of the flow to design a new particle separation method. The process has significant potential advantages over traditional methods, such as membrane-based separations. The goal of the research is to design a continuous, stagewise separation process that requires little maintenance or control, is relatively insensitive to ambient conditions such as temperature and pressure, and requires no purging or disposal of filter elements.