基于Level Set方法的气-液-固三相流动模型与模拟

Modeling and Simulation of Gas-Liquid-Solid Three-Phase Flows Based on Level Set Method

采用基于Level Set方法与离散颗粒模型相结合的方法,建立了一个用于描述气液固三相流动的新模型。模型耦合了颗粒与气泡、颗粒与液相以及气泡与液相之间的相互作用。应用该模型对液固悬浮液中的典型现象——气泡的单孔及多孔形成过程以及颗粒夹带现象进行了三维模拟,检验了其可行性。并进一步研究了颗粒的存在对气泡的形成与上升过程的影响以及气泡诱导的液相流动对颗粒行为的影响。研究结果表明,所提出的模型能够真实地预测三相流中气泡与颗粒分散相的特征,为研究多尺度的三相流动提供了一种新途径。

A new model is presented for three-dimensional simulation of gas-liquid-solid three-phase flows based on a combined level set method and discrete particle approach, where the various interactions of particle-bubble, bubble-liquid, and particle-liquid are taken into account. The validity of the simulation following this model is examined through several typical three-phase flow phenomena including the bubble formation and rising from single orifice and multi-orifices, and the particle entrainment in liquid-solid suspensions. The particle effect on bubble formation and rising has been studied focusing on the effect whether the particles are present or not, and the effect of bubble-induced liquid flow on the particle behavior is investigated. The simulated results coincide well with the experimental findings. The presented model can predict the characteristics of discrete phases, i. e., bubble and particle, in three-phase flows.