Direct numerical simulation of binary off-center collisions of shear thinning droplets at high Weber numbers
Direct numerical simulation of binary off-center collisions of shear thinning droplets at high Weber numbers
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DOI：
10.1063/1.4737582
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发表时间：
2012-07-01
影响因子：
4.6
通讯作者：
Bothe, D.
中科院分区：
文献类型：
--
作者：
Focke, C.;Bothe, D.
采用基于扩展流体体积法的直接数值模拟（DNS）研究了二元液滴碰撞这一典型的喷雾内部基本子过程。我们关注的是剪切变薄的液滴碰撞。为了捕捉具有不同结果的液滴碰撞动力学，我们考虑了高韦伯数下的偏心碰撞。这种碰撞条件导致极薄的流体片层的形成。结果表明，这些薄片决定了必须在DNS中解析的最小长度尺度。提出了一种防止片层破裂的稳定算法。通过与实验数据的对比验证了该方法的有效性，并将其应用于剪切变稀液体的液滴碰撞研究。结果表明，在不考虑碰撞液滴偏移的情况下，选择适当粘度的牛顿液滴碰撞可以再现剪切减薄液滴的碰撞动力学。这包括形状和能量的时间演化。(C) 2012年美国物理研究所。[http://dx.doi.org/10.1063/1.4737582]
Binary droplet collisions, a prototype elementary subprocess inside sprays, are investigated by direct numerical simulations (DNS) based on an extended volume of fluid method. We focus on shear-thinning droplet collisions. In order to capture the dynamics of droplet collisions with different outcomes, we account for off-center collisions at high Weber numbers. Such collision conditions lead to the formation of extremely thin fluid lamellae. It turns out that these thin lamellae determine the smallest length scales which must be resolved in a DNS. A stabilization algorithm is presented which prevents the lamellae from rupturing. It is validated by comparison with experimental data and applied for a droplet collision study of shear-thinning liquids. The results show that, independent of the off-set of the colliding droplets, a collision of Newtonian liquid droplets with appropriately chosen viscosity can reproduce the collision dynamics of the shear-thinning liquid droplets. This includes temporal evolution of shapes and energy. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4737582]