Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering, Southeast University, Nanjing 211189, China.
Biomicrofluidics. 2013 Jun 26;7(3):34113. doi: 10.1063/1.4812456. eCollection 2013.
This paper applies the lattice Boltzmann method (LBM) to a 3D simulation of micro flows in an expansion-contraction microchannel. We investigate the flow field under various inlet flow rates and cavity structures, and then systematically study the flow features of the vortex and Dean flow in this channel. Vortex formation analysis demonstrates that there is no observable vortex generated when the inlet flow rate is low enough. As the inlet flow rate increases, a small vortex first appears near the inlet, and then this vortex region will keep expanding until it fully occupies the cavity. A smaller cavity width may result in a larger vortex but the vortex is less influenced by cavity length. The Dean flow features at the outlet become more apparent with increasing inlet flow rate and more recirculation regions can be observed in the cross-section under over high inlet flow rate. In order to support the simulation results, some experimental processes are conducted successfully. It validates that the applied model can accurately characterize the flow in the microchannel. Results of simulations and experiments in this paper provide insights into the design and operation of microfluidic systems for particle/cell manipulation.
本文应用格子玻尔兹曼方法（LBM）对微通道中扩张-收缩微流的三维模拟。我们研究了在各种入口流速和腔结构下的流场，然后系统地研究了该通道中涡和迪恩流的流动特性。涡形成分析表明，当入口流速足够低时，不会产生可观察到的涡。随着入口流速的增加，首先在入口附近出现一个小涡，然后该涡区将不断扩大，直到完全占据腔。较小的腔宽可能导致较大的涡，但涡受腔长的影响较小。随着入口流速的增加，出口处的迪恩流特征变得更加明显，在过高的入口流速下，在横截面中可以观察到更多的再循环区域。为了支持模拟结果，成功地进行了一些实验过程。验证了所应用的模型可以准确地描述微通道中的流动。本文的模拟和实验结果为粒子/细胞操作的微流控系统的设计和操作提供了深入的了解。
