矩形斜板湿法除尘塔气液两相流数值模拟

Numerical Simulation of the Gas-liquid Two-phase Flow in the Tower with Sloping Plates for Wet Dusting and FGD

以自主研制的矩形斜板湿法除尘塔为物理模型,采用CFD(计算流体力学)软件Fluent对塔内三维气液两相的流场进行了数值模拟.计算中气相采用标准k-ε湍流模型,液相采用拉格朗日离散相模型,液滴的壁面行为采用壁面液膜模型.结果表明:矩形斜板除尘塔能有效地增大气液接触面积,增强气液扰动,延长气体在塔内的停留时间;在塔体的进口区域会出现烟气冲壁和液滴冲壁的现象;在进气管一侧的塔体顶部会出现流动死区;喷淋液体对气场有一定的整流作用,在喷嘴处可以观察到气体卷吸的现象;增大进口烟速,可增大液滴在塔内的充满度,但同时会出现液滴夹带的现象.最后,在不同气速,不同的液气比下对塔内的压力损失进行了实验验证,实验值与模拟值吻合较好.

The gas-liquid two-phase flow in the tower with the rectangle sloping plates for wet dusting, designed by us, was simulated by using Fluent package. The turbulent flow of gas phase was modeled by the standard k-εturbulent model, while the liquid flow was based on the Lagrange Discrete Phase Model of muitiphase flow, and the behavior of liquid particle on the wall was simulated by a wall-film model. Simulation results showed that the gas could be purified with high efficiency in the tower with the rectangle sloping plates by increasing gas-fluid contact area, intensifying the gas-liquid disturbance and delaying the gas residence time; there existed the phenomenon that the gas and the liquid impinged against the inlet wall of the tower and the dead area on the top of the inlet side of the tower; the spray liquid droplets played an intensive flow straightening role with regard to the gas flow field; the suction of gas was observed in the region of nuzzles; when the inlet velocity of the gas phase was bigger, the volume percentage of liquid in the tower increased, and this might cause liquid entrainment. Finally, test experiments were carried out, and the results showed that the experiment data agreed well with the simulation data.