气液两相流摆动特性实验的数值模拟

Numerical Simulation of the Oscillating Gas-Liquid Flow Experiment

为了给鼓泡塔反应器设计提供依据,运用计算流体力学(CFD)软件模拟了鼓泡塔气液两相流动态行为。采用双欧拉法对鼓泡塔矩形反应器内不同曝气量下气液两相流的摆动特性进行了模拟考察,液相采用标准κ-ε紊流模型,气相采用分散相零方程模型,分析了网格尺寸、时间步长以及相间作用力对模拟结果的影响,模拟的曝气量为42.5~237 m L/s。结果表明,当相间作用力仅考虑阻力时,气液两相流呈现周期性摆动规律;随着气流量的增加,气泡羽流的摆动幅度和频率增大,同时液体的气含率也在增加;模拟的气液两相流摆动频率数据与实验值吻合较好,两者的相对误差为7.2%~12.9%。

The numerical simulation of computational fluid dynamics(CFD) software was used to simulate the dynamic behavior of gas liquid two-phase flow in the bubble column reactor to provide the basis for the design of bubbling tower. Simulation study by Eulerian-Eulerian approach has been made for the oscillation characteristics of gas-liquid two-phase flow in different aeration units in a rectangular reactor. The influence of grid size, time step and interphase force on the simulation was analyzed using the standard k-ε turbulence model for liquid phase and the dispersed phase zero equation model for gas phase. The gas flow rates ranging from 42.5 to 237 m L/s were used for simulation. The results revealed that the gas-liquid two-phase flow exhibited the periodic oscillation law if resistance was considered as the only interphase force. With the increase of air flow, the amplitude and frequency of the bubble plume increased, and the gas hold up increased. The simulated frequency of gas-liquid two-phase bubble flow oscillation was in good agreement with the experimental results, and the relative error was 7.2%-12.9%.