Droplet-droplet interactions of highly viscous liquid suspensions have a major impact in industrial processes such as spray drying, fuel combustion or waste treatment. The efficiency of these processes depends heavily on the morphology of the droplets after the collision (i.e., surface area and volume). Although often encountered, the physical mechanisms overning merging and break-up of non-Newtonian droplets are largely unknown. It is therefore of paramount importance to gain a better understanding of the complex physics dominating the collision of non-Newtonian droplets. In this research, we investigate numerically the collision of droplets using the Local Front Reconstruction Method (LFRM) and the Volume of Fluid (VOF) method. The coalescence and stretching separation regime are studied using a xanthan solution, whose shear thinning rheology is described with the Carreau-Yasuda model. The capabilities of the two methods to capture the complex topological changes are assessed by a one-to-one comparison of the numerical results with experiments for near head-on collisions at various We numbers.

中文翻译：

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使用流体体积（VOF）和局部前沿重建方法（LFRM）对非牛顿液滴-液滴碰撞的数值研究

高粘性液体悬浮液的液滴-液滴相互作用对喷雾干燥、燃料燃烧或废物处理等工业过程产生重大影响。这些过程的效率在很大程度上取决于碰撞后液滴的形态（即表面积和体积）。尽管经常遇到，但非牛顿液滴合并和分裂的物理机制在很大程度上是未知的。因此，更好地理解主导非牛顿液滴碰撞的复杂物理原理至关重要。在本研究中，我们使用局部前沿重建方法（LFRM）和流体体积（VOF）方法对液滴碰撞进行数值研究。使用黄原胶溶液研究聚结和拉伸分离状态，其剪切稀化流变学用 Carreau-Yasuda 模型描述。通过将数值结果与不同 We 数的近正面碰撞实验进行一对一比较，评估这两种方法捕获复杂拓扑变化的能力。