填料塔气体分布器二相流场计算流体力学数值模拟

填料塔内气体分布器对进料气流的分布作用和填料塔的分离效率,特别是对低压降、高效填料有重大影响。文中运用计算流体力学(简称CFD),采用欧拉-拉格朗日二相流模型建立了填料塔内双切向气体分布器内三维瞬态气液二相流模型,气体的湍流运动采用k-ε湍流模型计算。模型中考虑了二相之间的作用力,包括液滴所受的曳力和虚拟质量力。求解时时间项采用隐式格式,时间步长取1×10-4s,对流项采用二阶迎风格式,压力-速度耦合方程的求解采用了S imp lec方法。在不同操作条件下,模型计算得到的压降、夹带、气体分布不均匀度和文献报道的实验值吻合较好。从而可以看出,CFD模型可以较为准确地描述双切向环流式气体分布器内瞬时气液二相流场。

Computational fluid dynamics simulations on two-phase flow field of gas distributor in packing column

Good performance of packing,especially high efficient and low pressure drop packing,depends critically on gas(vapor) distribution.Based on EulerLagrangian multiphase model,computational fluid dynamics(CFD) was carried out to develop a three-dimensional two-phase flow model of twin-tangential annular deflector gas distributor in packing column to predict the two phase hydraulics in gas distributor.In this model,the correlation of interphase force,including drag force and virtual mass force,was used to provide the closure relation for the model.The k-ε turbulence model was applied to simulate gas turbulent flow,and model was solved by Fluent.The pressure-velocity coupling was obtained by using the Simplec algorithm.A fully implicit backward differencing scheme was used for the time integration,and the time step was 1×10-4 s.The simulation results,including pressure drop,entrainment rate and maldistributed factor,agreed well with the experimental data.CFD can be a powerful tool for modeling and design of gas distributor in packing column.