Numerical investigation of multistability in the unstable flow of a polymer solution through porous media
Numerical investigation of multistability in the unstable flow of a polymer solution through porous media
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DOI：
10.1103/physrevfluids.6.033304
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发表时间：
2021-03-25
影响因子：
2.7
通讯作者：
Ardekani, Arezoo M.
中科院分区：
文献类型：
--
作者：
Kumar, Manish;Aramideh, Soroush;Ardekani, Arezoo M.
粘弹性聚合物流体通过多孔介质的流动在诸如石油回收和地下水修复的工业应用中是常见的。聚合物应力可导致流动的弹性诱导的不稳定性。在这里，我们数值研究了聚合物流体在通道中的流动，该通道由多个发散和收敛的物理约束组成，模仿有序多孔介质的孔隙体和喉部。这里的惯性应力可以忽略不计，相反，流动由弹性和粘性主导;它们的相对影响由韦森伯格数表征。存在一个临界Weissenberg数，低于该临界值，每个孔隙的顶部和底部都会出现漩涡。在临界Weissenberg数以上，在孔隙的不同区域形成涡流，并且出现多个不同的不稳定流动结构。孔内拉伸的聚合物链促进涡流形成，而松弛的链导致无涡流区域。我们量化的涡流面积和不同的孔隙对的流动模式之间的相关性，以及聚合物的应力和压力下降整个曲折的通道，以更好地了解所观察到的流动模式背后的机制。
The flow of viscoelastic polymeric fluids through porous media is common in industrial applications such as oil recovery and groundwater remediation. Polymeric stresses can lead to an elastic-induced instability of the flow. Here, we numerically study the flow of a polymeric fluid in a channel consisting of multiple diverging and converging physical constraints, mimicking the pore bodies and throats of an ordered porous medium. Inertial stresses here are negligible, and instead the flow is dominated by elasticity and viscosity; their relative effects are characterized by the Weissenberg number. There is a critical Weissenberg number below which eddies appear on the top and the bottom of each pore. Above the critical Weissenberg number, eddies form in different regions of the pores and multiple distinct unstable flow structures occur. The stretched polymeric chains inside the pore facilitate eddy formation, whereas relaxed chains lead to eddy-free regions. We quantify the eddy area and correlations between the flow patterns of different pairs of pores, as well as polymeric stress and pressure drop across the tortuous channel to better understand the mechanism behind the observed flow patterns.