规整填料塔内气相流动的计算流体力学模拟

CFD Simulations of Single-Phase Gas Flow in a Structured Packing Column

通过引入表征体元的概念,采用体积平均的方法,使规整填料塔内的非连续介质连续化,建立了规整填料塔内气相单相流的体积平均连续性方程、运动方程和质量传递方程;用PHOENICS3.3对规整填料塔内气相单相流的速度分布和质量分数分布进行了模拟,给出了xz剖面的压力分布图、xz和xy剖面的速度分布图和不同时刻xz剖面的示踪剂浓度分布图;模拟结果能反映规整填料内气体的流动情况.结果表明:在压力小于2.0MPa时,气相轴向返混系数基本不受压力的影响,且随着有效气速的增加,其明显增加;轴向返混系数的模拟值与实验值的相对偏差小于4000.

According to the definition of the representative elementary unit (REU), the averaged volume technique was applied to the averaged volume continuity equation, momentum equation and mass transfer equation under single-phase gas flow conditions. A commercial computational fluid dynamics (CFD) code, PHOENICS3.3, was used to predict the profile of pressure in xz cross-section, the profiles of gas velocity in xz and xy cross-sections and the profile of gas tracer concentration in xz cross-section at different time steps. The simulated results predicte the gas flow behaviors in structured packings. The results indicate that axial backmixing in gas phase increases notably with gas flowrate and slightly with pressure when the operating pressures are less than 2.0 MPa. The relative deviations of the simulated axial back-mixing coefficients from the experimental ones are less than 40%.