格子Boltzmann方法分析气泡的运动及其相互作用

Analysis of bubbles motions and their interaction using lattice Boltzmann method

利用格子Boltzmann方法对气泡在液体中的运动规律及相互作用的气液两相流问题进行了研究;采用了基于自由能模型且适用于大密度比多相流问题的Z-S-C模型,计算模拟了处于不可压缩流体中的气泡在浮力作用下的运动特性;通过算例验证了Z-S-C模型的可行性;研究了不同放置位置两气泡的运动形态及其相互作用情况,分别分析了沿y方向同轴放置的两气泡间距变化对合并过程和沿x方向并列放置的两气泡的间距变化对气泡相互作用的影响。结果表明:两气泡的初始间距在一定范围内时,初始间距对上升过程中气泡间的相互作用具有重要影响;当初始间距超过一定量值时,上升过程中两气泡相互独立,不存在相互作用。

A numerical study on the motion and interaction between two bubbles is carried out by using Lattice Boltzmann method. The motion characteristics of two bubbles due to buoyancy are systematically investigated. Z-S-C model which is based on free energy model and suitable for large density ratio is used to simulate this gas-liquid two-phase flow problem. The feasibility of this method is firstly examined by an example. The simulations are respectively performed for two coaxial bubbles and two abreast bubbles. Special attention is paid to investigate the change of the distance between two bubbles. Present results reveal that the initial spacing has a significant effect on the interaction of two rising bubbles when the initial distance between two bubbles do not exceed a certain value. Once the initial distance between two bubbles is larger enough, there is no interaction between the two bubbles.