Shen Shaofei, Gao Mengqi, Zhang Fangjuan, Niu Yanbing
College of Life Science, Shanxi Agricultural University, Taigu 030801, China.
Micromachines (Basel). 2021 Jan 14;12(1):81. doi: 10.3390/mi12010081.
The field of inertial microfluidics has been significantly advanced in terms of application to fluid manipulation for biological analysis, materials synthesis, and chemical process control. Because of their superior benefits such as high-throughput, simplicity, and accurate manipulation, inertial microfluidics designs incorporating channel geometries generating Dean vortexes and helical vortexes have been studied extensively. However, existing technologies have not been studied by designing low-aspect-ratio microchannels to produce multi-vortexes. In this study, an inertial microfluidic device was developed, allowing the generation and regulation of the Dean vortex and helical vortex through the introduction of micro-obstacles in a semicircular microchannel with ultra-low aspect ratio. Multi-vortex formations in the vertical and horizontal planes of four dimension-confined curved channels were analyzed at different flow rates. Moreover, the regulation mechanisms of the multi-vortex were studied systematically by altering the micro-obstacle length and channel height. Through numerical simulation, the regulation of dimensional confinement in the microchannel is verified to induce the Dean vortex and helical vortex with different magnitudes and distributions. The results provide insights into the geometry-induced secondary flow mechanism, which can inspire simple and easily built planar 2D microchannel systems with low-aspect-ratio design with application in fluid manipulations for chemical engineering and bioengineering.
在应用于生物分析、材料合成和化学过程控制的流体操纵方面，惯性微流体领域取得了显著进展。由于其具有高通量、简单性和精确操纵等卓越优势，包含产生迪恩涡旋和螺旋涡旋的通道几何结构的惯性微流体设计已得到广泛研究。然而，现有技术尚未通过设计低纵横比微通道来产生多涡旋进行研究。在本研究中，开发了一种惯性微流体装置，通过在超低纵横比的半圆形微通道中引入微障碍物，实现迪恩涡旋和螺旋涡旋的产生与调控。分析了在不同流速下，四维受限弯曲通道垂直和水平平面内的多涡旋形成情况。此外，通过改变微障碍物长度和通道高度，系统地研究了多涡旋的调控机制。通过数值模拟，验证了微通道中尺寸限制的调控可诱导出不同大小和分布的迪恩涡旋和螺旋涡旋。这些结果为几何诱导二次流机制提供了见解，可启发设计简单且易于构建的具有低纵横比设计的平面二维微通道系统，应用于化学工程和生物工程的流体操纵。
