Deformation of a viscoelastic droplet passing through a microfluidic contraction
Deformation of a viscoelastic droplet passing through a microfluidic contraction
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DOI：
10.1016/j.jnnfm.2008.05.002
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发表时间：
2008-11-01
影响因子：
3.1
通讯作者：
Davidson, M. R.
中科院分区：
文献类型：
--
作者：
Harvie, D. J. E.;Cooper-White, J. J.;Davidson, M. R.
使用流体体积法来模拟不混溶相行为的计算流体动力学算法适用于模拟粘弹流体的流动。通过收缩的粘弹性液滴的二维笛卡尔模拟与使用三维平面收缩产生的实验结果进行比较。粘弹性效应使用Oldrophil-B流变模型进行模拟。物理和数值模型捕捉变形过程，特别是特征分叉的尾巴上的粘弹性液滴，而它是在收缩。在实验中观察到了连续相流体的包封，但模拟没有预测到。我们认为这是由于在细螺纹夹带过程的长度尺度上网格细化不足。数值结果表明，液滴内存在弹性应力，可能导致夹带和随后的封装。该方法在微米级药物和化学品递送胶囊的制造中具有应用潜力。(C)2008 Elsevier B. V.保留所有权利。
A computational fluid dynamics algorithm that uses a volume of fluid method to model immiscible phase behaviour is adapted to simulate the flow of viscoelastic fluids. Two-dimensional Cartesian simulations of a viscoelastic droplet passing through a contraction are compared against experimental results generated using a three-dimensional planar contraction. Viscoelastic effects are simulated using the Oldroyd-B rheological model. The physical and numerical models capture the deformation process well, particularly the characteristic forked tail that develops on the viscoelastic droplet while it is within the contraction. Encapsulation of continuous phase fluid is observed in the experiments, but not predicted by the simulations. We suggest this is due to inadequate mesh refinement at the length scale of a fine thread entrainment process. The numerical results show the existence of an elastic stress within the droplet that could cause the entrainment and subsequent encapsulation. The process has application potential in the manufacture of micron-sized drug and chemical delivery capsules. (C) 2008 Elsevier B.V. All rights reserved.