We compare the flow behavior of viscoelastic surfactant (VES) solutions and Newtonian fluids through two different model porous media having similar permeability: (a) a 3D random packed bed and (b) a microchannel with a periodically spaced pillars. The former provides much larger flow resistance at the same apparent shear rate compared to the latter. The flow profile in the 3D packed bed cannot be observed since it is a closed system. However, visualization of the flow profile in the microchannel shows strong spatial and temporal flow instabilities in VES fluids appear above a critical shear rate. The onset of such elastic instabilities correlates to the flow rate where increased flow resistance is observed. The elastic instabilities are attributed to the formation of transient shear induced structures. The experiments provide a detailed insight into the complex interplay between the pore scale geometry and rheology of VES in the creeping flow regime. © 2017 American Institute of Chemical Engineers AIChE J, 2017

中文翻译：

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粘弹性表面活性剂通过多孔介质的流动

我们比较了粘弹性表面活性剂（VES）溶液和牛顿流体通过两种具有相似渗透率的不同模型多孔介质的流动行为：（a）3D随机填充床和（b）具有周期性间隔的支柱的微通道。与后者相比，前者在相同的表观剪切速率下提供了更大的流阻。由于是封闭系统，因此无法观察3D填充床中的流量分布。但是，微通道中流动剖面的可视化显示，在临界剪切速率以上时，VES流体中存在强烈的时空流动不稳定性。这种弹性不稳定性的发生与观察到流动阻力增加的流速有关。弹性不稳定性归因于瞬态剪切诱导结构的形成。实验提供了对蠕变流态中VES的孔尺度几何结构和流变学之间复杂相互作用的详细了解。©2017美国化学工程师学会AIChE的Ĵ，2017年