Quantitative characterization of high molecular weight polymer solutions in microfluidic hyperbolic contraction flow
Quantitative characterization of high molecular weight polymer solutions in microfluidic hyperbolic contraction flow
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DOI：
10.1007/s10404-014-1474-z
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发表时间：
2015-05
影响因子：
2.8
通讯作者：
A. Lanzaro;Zhuo Li;X. Yuan
中科院分区：
文献类型：
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作者：
A. Lanzaro;Zhuo Li;X. Yuan
利用微粒子图像测速（-PIV）技术，研究了聚丙烯酰胺（PAAm）水溶液在高亨基应变（Hencky strain）条件下的非线性流动。在Weissenberg数（Wi）和雷诺数（Re）范围内的各种流动动力学形式在aWi-Rediagram中显示。对称角涡只在低浓度PAAm溶液流动中观察到（）。在较高的浓度（）下，PAAm溶液在强非线性流态（）下表现出类似混沌的流动模式。本文分析了860w以下非线性流场的拉伸变形。此外，系统地量化了聚合物链在复杂流动中所经历的局部拉伸，并将其与相应的速度矢量场联系起来，这对理解高度非线性的流动现象有价值。
Nonlinear flows of polyacrylamide (PAAm) () aqueous solutions through a micro-fabricated, hyperbolic contraction geometry with high Hencky strain () have been characterized by micro-particle image velocimetry (-PIV). Various flow dynamics regimes in a range of Weissenberg number (Wi) and Reynolds number (Re) are presented in aWi–Rediagram. The symmetric corner vortices are only observed in the flow of low concentration PAAm solution (). In a higher concentration (), PAAm solution exhibits chaotic-like flow patterns in the strong nonlinear flow regime (). Extensional deformation in nonlinear flows ofWiup to 860 has been analyzed. Furthermore, the local stretch experienced by the polymer chain in complex flow is systematically quantified and linked to the corresponding velocity vector fields, which are valuable for understanding the highly nonlinear flow phenomena.