基于三维VOF模型的变径水平管道气体运动模拟研究

介绍了VOF模型及其控制方程．结合k-ε湍流模型，对三维变径水平管道模型进行了气体运动模拟研究．模拟结果与Fagundes气泡形状以及Bendiksen气泡速度计算式较好吻合．研究表明：气体通过变径节点时，气液界面产生弯曲和波浪，并且管段截面气相所占面积减少；管径收缩增强使气体通过变径节点收缩长度增长，流体充分发展距离增加；靠近变径节点处，管道截面流速分布与变径管段管径差值大小有直接关系，变径程度越大，中心速度越突出．

Research on Gas Motion in Horizontal Reducer Pipelines Based on 3-D VOF Model

The volume of fluid （VOF） model and its governing equations are presented in this paper. A three- dimensional model of horizontal reducer pipelines is solved by using k ~8 turbulent model. Simulation results are matched with data reported by Fagundes and Bendiksen,respectively. The result reveals that the air and water interface tends to become concave and wavy while fluid travels through the connection of the reducer. The length of fully developed flow increases along with increasing pipe contraction. The velocity profiles appear to be prominent in the center of the pipe ahead of the connection. Axial velocity profiles in the horizontal centerline remain symmetrical, but velocity profiles in vertical centerline have velocity peaks near the top of the pipe, where the gas phase exists. Reduction of pipe diameter causes unbalanced increase of gas and liquid velocities, leading to significant non-uniform increase in wall shear stress. The greater the variable degree of pipeline diameter is, the more prominent the centerline velocity is.