曝气池内气液两相流CFD模拟

对曝气池反应器内的气液两相流动进行了三维瞬态数值模拟,模拟采取了双流体模型,液相湍流采用标准k-ε方程,两相间的动量传递只考虑曳力作用。模拟获得了曝气池内的液速及不同径向位置的轴向液速分布、气含率分布等,结果表明,气泡刚开始以直线垂直上升,过一段时间后,气泡的运动开始偏离轴中心,气泡群开始发生了摆动;随着气体速度增大,气含率分布变宽,气含率增大,液体循环液速也在增大,气液之间混合越充分,曝气效果越好。

CFD Simulation of Gas-liquid Flow in Aeration Tank

Three-dimensional numerical simulations of gas-liquid flow in aeration tank with two-fluid approach were conducted. A standard k-ε turbulence model was used to describe liquid phase turbulence in the simulations, which only adopted the drag force for interphase momentum transfer. The liquid velocities, axial liquid velocities and gas holdup distribution in the different radial positions were obtained in the simulations. The results showed that at first bubbles ascended vertically as straight line and then the line began to swing around the central shaft. With the increase of gas velocity, the gas holdup and liquid circulation rate increased. As we know, the more sufficiently gas and liquid mix, the better the aeration effect would be.