Centro de Física Teórica e Computacional, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal and Departamento de Física, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal.
Phys Rev E. 2023 Mar;107(3-2):035106. doi: 10.1103/PhysRevE.107.035106.
Droplets suspended in fluids flowing through microchannels are often encountered in different contexts and scales, from oil extraction down to microfluidics. They are usually flexible and deform as a product of the interplay between flexibility, hydrodynamics, and interaction with confining walls. Deformability adds distinct characteristics to the nature of the flow of these droplets. We simulate deformable droplets suspended in a fluid at a high volume fraction flowing through a cylindrical wetting channel. We find a discontinuous shear thinning transition, which depends on the droplet deformability. The capillary number is the main dimensionless parameter that controls the transition. Previous results have focused on two-dimensional configurations. Here we show that, in three dimensions, even the velocity profile is different. To perform this study, we improve and extend to three dimensions a multicomponent lattice Boltzmann method which prevents the coalescence between the droplets.
在不同的背景和尺度下，包括从采油到微流控，都经常会遇到在微通道中流动的流体中的液滴。这些液滴通常具有弹性，并会发生变形，这是其柔韧性、流体动力学和与约束壁相互作用的综合结果。变形性为这些液滴的流动性质增添了独特的特征。我们模拟了高体积分数的流体中悬浮的可变形液滴在圆柱润湿通道中的流动。我们发现了一种不连续的剪切稀化转变，其取决于液滴的变形性。卡数是控制该转变的主要无量纲参数。之前的结果主要集中在二维配置上。在这里，我们表明，即使在三维情况下，速度分布也有所不同。为了进行这项研究，我们改进并扩展了多组分格子玻尔兹曼方法以防止液滴的聚并，并将其应用于三维情况。
