相同尺度下气泡与复杂壁面的耦合特性研究

采用格子Boltzmann方法(LBM)建立了气液固三相耦合的动力学模型,研究了相同尺度下上浮气泡与复杂壁面的相互耦合作用.首先,基于黏性流体理论,通过构建一组格子Boltzmann(LB)方程来描述气液两相的运动,并以LB离散体积力的形式计入了黏性力、表面张力和重力.同时,采用LBM中的Half-way反弹模型与有限差分格式相结合的方式进行固壁边界的处理.然后,利用本文建立的模型,对不同特征尺寸比条件下,气泡与考虑边缘效应的平面固壁和曲面固壁的耦合特性进行了研究.研究发现固壁边界条件以及特征尺寸比对气泡的运动和拓扑结构的变化都具有明显的非线性影响.最后,研究了流体属性对气泡与复杂壁面耦合规律的影响.

Study on coupling characteristics b etween bubble and complex walls at the same scale

A gas-liquid-solid three-phase coupling dynamic model is established using lattice Boltzmann method (LBM). Interaction between rising bubble and complex solid walls at the same scale is studied. Firstly, based on the viscous fluid theory, a group of lattice Boltzmann equations are developed to describe the gas-liquid two-phase campaign by considering the viscosity, surface tension, and gravity in the form of a LB discrete body force. At the same time, combined with the finite difference scheme, the half-way bounce back model in LBM is adopted to deal with the solid boundary condition. Then, under the conditions of different feature size ratios, the coupling characteristics between bubbles and plane wall, taking into consideration the effect of boundaries and curved wall, are studied using the newly built model. Results show that both the solid wall condition and the feature size ratio have significant nonlinear effects on bubble movement and topology changes. Finally, the effect of fluid properties on the coupling regularity of bubbles and complex walls is researched.
Keywords： lattice Boltzmann method bubble complex wall gas-liquid-solid coupling