Elastic instabilities between two cylinders confined in a channel
Elastic instabilities between two cylinders confined in a channel
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DOI：
10.1063/5.0057497
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发表时间：
2021-07-01
影响因子：
4.6
通讯作者：
Ardekani, Arezoo M.
中科院分区：
文献类型：
--
作者：
Kumar, Manish;Ardekani, Arezoo M.
聚合物在多孔介质中的流动在工业应用中是相关的，例如提高石油采收率、微生物开采和地下水修复。生物过程，如药物递送以及细胞和颗粒在体内的运输，也依赖于通过多孔基质的粘弹性流动。粘弹性流体在多孔介质中流动时，由于几何约束而产生的较大弹性应力会导致流体的弹性失稳。本文用数值方法研究了粘弹性流体通过两个相邻圆柱体的通道时的孔隙尺度弹性不稳定性。我们已经发现了三个不同的流动状态之间的区域的圆柱体。这些流动状态与聚合物应力场的拓扑结构密切相关。流动状态之间的转变可以用两个临界Weissenberg数（Wi（cr1）和Wi（cr2））来识别，其中Weissenberg数（Wi）是弹性力与粘性力的比率。当Wi <Wi（cr1）时，流动是稳定的、对称的和无涡流的。对于Wi（cr1）<Wi <Wi（cr2），在圆柱体之间的区域中形成涡流。我们测量了不同流动条件和流体流变参数下的涡所占的面积。当Wi> Wi（cr2）时，涡消失，圆柱绕流变得不对称。我们已经量化了不同流速和流体流变学的圆柱体周围的流动不对称性。本文还研究了圆柱直径和间距对涡的大小（Wi（cr1）<Wi <Wi（cr2））和流动不对称性（Wi> Wi（cr2））的影响。我们还研究了流体流变学和圆柱体直径和间距对临界Weissenberg数的影响。由AIP Publishing独家授权出版。
Polymeric flow through porous media is relevant in industrial applications, such as enhanced oil recovery, microbial mining, and groundwater remediation. Biological processes, such as drug delivery and the transport of cells and particles in the body, also depend on the viscoelastic flow through the porous matrix. Large elastic stresses induced due to confined geometries can lead to elastic instability for the viscoelastic fluid flow through porous media. We have numerically studied viscoelastic flow through a channel having two closely placed cylinders to investigate pore scale elastic instabilities. We have discovered three distinct flow states in the region between the cylinders. These flow states are closely coupled with the topology of the polymeric stress field. The transition between the flow states can be identified with two critical Weissenberg numbers (Wi(cr1) and Wi(cr2)), where the Weissenberg number (Wi) is the ratio of elastic to viscous forces. At Wi < Wi(cr1), the flow is stable, symmetric, and eddy free. For Wi(cr1) < Wi < Wi(cr2), eddies form in the region between the cylinders. We have measured the area occupied by the eddies for different flow conditions and fluid rheological parameters. At Wi > Wi(cr2), the eddy disappears and the flow around the cylinders becomes asymmetric. We have quantified the flow asymmetry around the cylinders for different flow rates and fluid rheology. We have also studied the effect of the cylinders' diameter and separation on the eddies' size (Wi(cr1) < Wi < Wi(cr2)) and flow asymmetry (Wi > Wi(cr2)). We have also investigated the effect of fluid rheology and cylinders' diameter and separation on the value of critical Weissenberg numbers. Published under an exclusive license by AIP Publishing.