气浮过程中油滴与气泡相互作用的数值模拟

Numerical simulation of the interaction between bubbles and oil drops in the gas floating process

分析了分散相液滴在水中的受力情况和上升速度的影响因素,采用Fluent软件与VOF多相流模型模拟了气泡在水中的上升过程,研究了影响气泡变形和上升速度的参数。研究发现:表面张力是维持气泡形状的主要因素;气泡的上升速度主要受黏度比和密度比影响:黏度比越大,上升越慢,密度比越大,上升越快。随后,模拟了气浮过程中气泡和油滴在水中相互作用的过程,对油滴在气泡表面的扩散情况进行了研究,研究表明:只有当热力学扩散系数为正时,油滴才能在气泡表面扩散,形成稳定的黏附关系,由气泡带着油滴上升;油滴与气泡的粒径差别过大时,两者无法形成稳定的黏附关系。

Firstly, the force situation and the factors influencing the ascensional velocity of the dispersed phase droplets in the wa- ter were analyzed. The software fluent and VOF multiphase flow model were used to simulate the rising process of bubbles in the water. The results of deformation and rising velocity of bubbles show that bubbles rely on the surface tension to maintain shape, and the viscosity ratio and density ratio have less impact on deformation. The rising velocity is mainly affected by viscosity ratio and density ratio~ the higher viscosity ratio leads to the lower rising velocity while the greater density ratio results in higher veloc- ity. Furthermore, the interaction between bubbles and oil droplets in the gas floating process in the water was simulated. The diffusion conditions of oil droplets on the bubble surface have been analyzed. It is shown that a only when the thermodynamic dif fusion coefficient is positive, could a stable adhesion be formed, and could bubbles rise with oil droplets; if the size difference be tween bubbles and oil droplets is too large, no stable adhesion could be formed.