Chen Dalin, Huang Qiang, Ni Zhonghua, Xiang Nan
School of Mechanical Engineering, and Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, Southeast University, Nanjing, P. R. China.
Electrophoresis. 2024 Dec;45(23-24):2191-2201. doi: 10.1002/elps.202400070. Epub 2024 May 30.
Dean flow existing in sinusoidal channels could enhance the throughput and efficiency for elasto-inertial particle focusing. However, the fundamental mechanisms of elasto-inertial focusing in sinusoidal channels are still unclear. This work employs four microfluidic devices with symmetric and asymmetric sinusoidal channels to explore the elasto-inertial focusing mechanisms over a wide range of flow rates. The effects of rheological property, flow rate, sinusoidal channel curvature, particle size, and asymmetric geometry on particle focusing performance are investigated. It is intriguing to find that the Dean flow makes a substantial contribution to the particle elasto-inertial focusing. The results illustrate that a better particle focusing performance and a faster focusing process are obtained in the sinusoidal channel with a small curvature radius due to stronger Dean flow. In addition, the particle focusing performance is also related to particle diameter and rheological properties, the larger particles show a better focusing performance than smaller particles, and the smaller flow rate is required for particles to achieve stable focusing at the outlet in the higher concentration of polyvinylpyrrolidone solutions. Our work offers an increased knowledge of the mechanisms of elasto-inertial focusing in sinusoidal channels. Ultimately, these results provide supportive guidelines into the design and development of sinusoidal elasto-inertial microfluidic devices for high-performance focusing.
存在于正弦通道中的Dean流可以提高弹性惯性粒子聚焦的通量和效率。然而，正弦通道中弹性惯性聚焦的基本机制仍不清楚。这项工作采用了四个具有对称和不对称正弦通道的微流体装置，以在广泛的流速范围内探索弹性惯性聚焦机制。研究了流变特性、流速、正弦通道曲率、颗粒尺寸和不对称几何形状对粒子聚焦性能的影响。有趣的是发现Dean流对粒子弹性惯性聚焦有重大贡献。结果表明，由于更强的Dean流，在曲率半径较小的正弦通道中可获得更好的粒子聚焦性能和更快的聚焦过程。此外，粒子聚焦性能还与粒径和流变特性有关，较大的粒子比较小的粒子表现出更好的聚焦性能，并且在较高浓度的聚乙烯吡咯烷酮溶液中，粒子在出口处实现稳定聚焦所需的流速较小。我们的工作增加了对正弦通道中弹性惯性聚焦机制的了解。最终，这些结果为高性能聚焦的正弦弹性惯性微流体装置的设计和开发提供了支持性指导方针。
