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美国卫生研究院文献>Biomicrofluidics
>Investigation of particle inertial migration in high particle concentration suspension flow by multi-electrodes sensing and Eulerian-Lagrangian simulation in a square microchannel
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Investigation of particle inertial migration in high particle concentration suspension flow by multi-electrodes sensing and Eulerian-Lagrangian simulation in a square microchannel
The inertial migration of neutrally buoyant spherical particles in high particle concentration (αpi > 3%) suspension flow in a square microchannel was investigated by means of the multi-electrodes sensing method which broke through the limitation of conventional optical measurement techniques in the high particle concentration suspensions due to interference from the large particle numbers. Based on the measured particle concentrations near the wall and at the corner of the square microchannel, particle cross-sectional migration ratios are calculated to quantitatively estimate the migration degree. As a result, particle migration to four stable equilibrium positions near the centre of each face of the square microchannel is found only in the cases of low initial particle concentration up to 5.0 v/v%, while the migration phenomenon becomes partial as the initial particle concentration achieves 10.0 v/v% and disappears in the cases of the initial particle concentration αpi ≥ 15%. In order to clarify the influential mechanism of particle-particle interaction on particle migration, an Eulerian-Lagrangian numerical model was proposed by employing the Lennard-Jones potential as the inter-particle potential, while the inertial lift coefficient is calculated by a pre-processed semi-analytical simulation. Moreover, based on the experimental and simulation results, a dimensionless number named migration index was proposed to evaluate the influence of the initial particle concentration on the particle migration phenomenon. The migration index less than 0.1 is found to denote obvious particle inertial migration, while a larger migration index denotes the absence of it. This index is helpful for estimation of the maximum initial particle concentration for the design of inertial microfluidic devices.
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机译：采用多电极传感方法研究了方形微通道中高浓度（αpi> 3％）悬浮液中的中性浮力球形颗粒的惯性迁移，突破了传统光学测量技术在高浓度颗粒中的局限性由于大颗粒的干扰而产生悬浮。根据壁附近和方形微通道拐角处测得的颗粒浓度，计算颗粒横截面迁移率，以定量估算迁移程度。结果，仅在初始颗粒浓度低至5.0 v / v％的情况下，才发现颗粒迁移到方形微通道每个面的中心附近的四个稳定平衡位置，而迁移现象作为初始颗粒变得部分浓度达到10.0 v / v％，并且在初始粒子浓度αpi≥15％时消失。为了阐明粒子间相互作用对粒子迁移的影响机理，以伦纳德-琼斯势为粒子间势，建立了欧拉-拉格朗日数值模型，并通过预处理计算出惯性升力系数。半分析模拟。此外，基于实验和模拟结果，提出了一个无量纲的数字，称为迁移指数，以评估初始粒子浓度对粒子迁移现象的影响。发现小于0.1的迁移指数表示明显的颗粒惯性迁移，而较大的迁移指数表示不存在。该指数有助于估计惯性微流体装置设计的最大初始颗粒浓度。
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