Microfluidic converging/diverging channels optimised for homogeneous extensional deformation.
Microfluidic converging/diverging channels optimised for homogeneous extensional deformation.
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DOI：
10.1063/1.4954814
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发表时间：
2016-07
期刊：
影响因子：
3.2
通讯作者：
Oliveira MS
中科院分区：
文献类型：
--
作者：
Zografos K;Pimenta F;Alves MA;Oliveira MS
在这项工作中，我们优化了微流体的收敛/发散几何形状，以便沿着流动的中线产生恒定的应变率，以便在均匀扩展下进行研究。该设计在二维和三维流动中进行了检验，其中研究了展弦比和无因次收缩长度的影响。首先，考虑了牛顿流体在爬行流动条件下的压力驱动流动，这是微流体学中一个合理的近似，并研究了基于雷诺数的设计的适用性限制。然后将优化后的几何结构用于粘弹性流体的流动研究，并报告了在Weissenberg数方面的实际限制。此外，该优化策略也适用于电渗透驱动的流体，在这种流体中，类似塞的速度剖面的发展允许流场中更广泛的均匀拉伸变形区域。
In this work, we optimise microfluidic converging/diverging geometries in order to produce constant strain-rates along the centreline of the flow, for performing studies under homogeneous extension. The design is examined for both two-dimensional and three-dimensional flows where the effects of aspect ratio and dimensionless contraction length are investigated. Initially, pressure driven flows of Newtonian fluids under creeping flow conditions are considered, which is a reasonable approximation in microfluidics, and the limits of the applicability of the design in terms of Reynolds numbers are investigated. The optimised geometry is then used for studying the flow of viscoelastic fluids and the practical limitations in terms of Weissenberg number are reported. Furthermore, the optimisation strategy is also applied for electro-osmotic driven flows, where the development of a plug-like velocity profile allows for a wider region of homogeneous extensional deformation in the flow field.