An experimental study of binary collisions of miscible droplets with non-identical viscosities
An experimental study of binary collisions of miscible droplets with non-identical viscosities
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DOI：
10.1007/s00348-019-2874-3
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发表时间：
2020-01
影响因子：
2.4
通讯作者：
Karrar H. Al-Dirawi;A. Bayly
中科院分区：
文献类型：
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作者：
Karrar H. Al-Dirawi;A. Bayly
摘要通过实验研究了具有不同粘度的等直径液滴的二元碰撞动力学，并与以前由相同液滴碰撞产生的数据(物理流体中的Al-Dirawi和Bayly)进行了比较31(2)：027105,2019年。使用2%、4%和8%羟丙基甲基纤维素(HPMC)的三种水溶液产生不同粘度的液滴，分别为2.8、8.2和28.4 Mpa(对S)。应用高速成像技术来观察和捕捉碰撞结果。对碰撞的结果进行了表征，并生成了制度地图。不同粘度的液滴碰撞产生了边界明确的制度图，其形状与相同液滴碰撞的传统制度图相当。非全同碰撞的反弹分离区和自反式分离区的边界在相同的低粘度液滴和高粘度液滴之间显示出中间位置。然而，非全同碰撞的拉伸分离区域的边界与相同情况下的低粘度液滴的边界表现出很好的一致性。此外，还评估了所开发的用于预测相同粘度液滴碰撞的区域边界的模型对于非相同碰撞的能力。事实证明，它们在不相同的情况下是可行的，可调参数的变化与模型的潜在物理基础是一致的。
AbstractThe dynamics of binary collisions of equi-diameter droplets with non-identical viscosities have been investigated experimentally and compared to previously generated data from identical droplet collisions (Al-Dirawi and Bayly in Phys Fluids 31(2):027105, 2019). Three hydroxypropyl methylcellulose (HPMC) aqueous solutions, 2%, 4%, and 8% HPMC, were used to generate the droplets of different viscosities, 2.8, 8.2, and 28.4 mPa s, respectively. High-speed imaging techniques were applied to observe and capture the collision outcomes. Collision outcomes were characterised and regime maps were generated. The non-identical viscosity droplet collisions produced regime maps with well-defined boundaries which are comparable in shape to the conventional regime maps of identical droplet collisions. The boundaries of the bouncing and reflexive separation regimes of the non-identical collisions show intermediate position between the identical cases of the low and the high viscosity droplets. However, the boundary of the stretching separation regimes of the non-identical collisions showed good agreement with the boundary of the identical case of the lower viscosity droplet. Moreover, the ability of models developed for predicting the regimes boundaries of collisions of identical viscosity droplets was assessed for the non-identical collisions. They proved capable in the non-identical cases, and the changes in adjustable parameters were consistent with the underlying physical basis of the models.Graphic abstract