Liu Yong, Zhang Jun, Peng Xiaobo, Yan Sheng
Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China.
College of Mechatronics and Control Engineering, Shenzhen University, Shenzhen 518060, China.
Anal Chem. 2024 Sep 3;96(35):14306-14314. doi: 10.1021/acs.analchem.4c03474. Epub 2024 Aug 21.
Serpentine channels coupling inertial and secondary flows enable effective particle focusing and separation, showing great potential in clinical diagnostics and drug screening. However, the nonsteady secondary flows in the serpentine channel make the evolution of inertial migration unclear, hindering the development and application of the serpentine channel. Herein, to refine the inertial migration mechanism, we established a model with varying curvature ratios to study the effect of secondary flow on particle migration in the serpentine channel. This method used direct numerical simulation (DNS) to calculate inertial lift, mapped the inertial lift to cross sections of the serpentine channel, and deciphered the inertial migration by using the Lagrangian particle tracking (LPT) method. The inertial migration of microparticles is experimentally investigated to validate the established numerical model. The results indicate that particle migration in serpentine channels follows a two-stage migration. An increase in secondary flow accelerates the second stage of the migration process while slowing the first stage process. Subsequently, we investigated the effects of different parameters, including Reynolds number, aspect ratio, and blockage ratio, on the equilibrium positions of particles, providing guidelines for the high-resolution separation of particles. Taking flow resistance into account, the dimensionless study makes the separation of arbitrary-sized particles possible. This work reveals the migration mechanism in serpentine channels, paving the way for the inertial separation of the particles.
耦合惯性流和二次流的蛇形通道能够实现有效的粒子聚焦和分离，在临床诊断和药物筛选方面显示出巨大潜力。然而，蛇形通道中的非稳态二次流使得惯性迁移的演变尚不清楚，阻碍了蛇形通道的发展和应用。在此，为了完善惯性迁移机制，我们建立了一个具有不同曲率比的模型，以研究二次流对蛇形通道中粒子迁移的影响。该方法采用直接数值模拟（DNS）来计算惯性升力，将惯性升力映射到蛇形通道的横截面上，并通过拉格朗日粒子跟踪（LPT）方法来解读惯性迁移。通过实验研究了微粒的惯性迁移，以验证所建立的数值模型。结果表明，蛇形通道中的粒子迁移遵循两阶段迁移。二次流的增加加速了迁移过程的第二阶段，同时减缓了第一阶段的过程。随后，我们研究了包括雷诺数、纵横比和阻塞比在内的不同参数对粒子平衡位置的影响，为粒子的高分辨率分离提供了指导。考虑到流动阻力，无量纲研究使得任意尺寸粒子的分离成为可能。这项工作揭示了蛇形通道中的迁移机制，为粒子的惯性分离铺平了道路。
