Swinburne University of Technology, Hawthorn, Victoria 3122, Australia.
Swinburne University of Technology, Hawthorn, Victoria 3122, Australia.
J Colloid Interface Sci. 2018 Feb 1;511:440-446. doi: 10.1016/j.jcis.2017.10.032. Epub 2017 Oct 10.
The three-dimensional flow in exterior microscale foams including the Plateau borders and nodes are investigated by solving Navier-stoke and continuity equations. First, we show the effect of the interfacial mobility and film thickness on the dimensionless mean velocity of the exterior foams. The velocity of the exterior node-PB is similar to the velocity of single exterior Plateau border. Next, we calculated the pressure difference of each element separately and obtained their hydraulic resistances. We found out that the hydraulic resistance of the exterior Plateau border is always larger than the hydraulic resistance of the exterior node, resulting in a consistent channel-dominated regime. However, For the interior foams, there is a value of interfacial mobility where the node's resistance overcomes the channel's resistance, resulting in a switch from the channel-dominated regime to a node-dominated regime. This switching point is dependent on the relative length of the channels. Hence, we obtained an approximation of the interfacial mobility switching points versus the relative length of channels. Moreover, in a form of approximation master curve, we showed the dependence of mean velocities of foams and channels' hydraulic resistances to a dimensionless combined parameter of Λ that contains interfacial mobility and film thickness together. For both the exterior and interior nodes, the velocity and hydraulic resistance are almost constant for various Boussinesq numbers since interfacial mobility has a marginal effect on node's flow.
通过求解纳维-斯托克斯方程和连续性方程，研究了包括 Plateau 边界和节点在内的外部微泡中的三维流动。首先，我们展示了界面迁移率和薄膜厚度对外部泡沫无量纲平均速度的影响。外部节点-PB 的速度与单个外部 Plateau 边界的速度相似。接下来，我们分别计算每个单元的压力差，并获得它们的水力阻力。我们发现外部 Plateau 边界的水力阻力总是大于外部节点的水力阻力，导致一致的通道主导模式。然而，对于内部泡沫，存在一个界面迁移率值，其中节点的阻力超过通道的阻力，导致从通道主导模式切换到节点主导模式。该切换点取决于通道的相对长度。因此，我们获得了界面迁移率切换点与通道相对长度之间的近似关系。此外，我们以近似主曲线的形式，展示了泡沫的平均速度和通道水力阻力对包含界面迁移率和薄膜厚度的无量纲组合参数 Λ 的依赖性。对于外部和内部节点，由于界面迁移率对节点流动的影响较小，因此节点的速度和水力阻力对于各种 Boussinesq 数几乎是恒定的。
