竖直管内降膜流动气液两相运动数值模拟

Numerical simulation on gas-liquid two-phase motion of falling film in vertical tube

对较高流速下强迫竖直降膜进行了模拟。建立了描述竖直管内强迫降膜的物理模型和数学模型,采用RNGk-ε模型描述管内气体和液体的复杂湍流流动过程,采用VOF方法对气液相界面进行追踪。通过观察流动过程中的液膜前端速度矢量变化、整个流场中的压力分布变化过程,对降膜前端的"托举"现象进行了分析,对竖直管内液膜形成过程中的两相复杂运动进行了分析研究,指出了避免"托举"现象出现的条件。

The high velocity falling film was studied. Physics model and math model were proposed separately, κ-ε model was used to simulate the turbulent flow of the gas and slag on the wall, and VOF method was used to simulate the free surface between the gas and liquid. The influences of ‘hold’ were discussed based on the analyses of velocity vector in the front of falling films and the varieties of pressure in the tube. The conditions of voiding ‘hold’ were found by analyzing the forming of falling films.