气升式环流反应器内气液两相流动计算流体力学的模拟

Computational Fluid Dynamic Simulation on Gas-Liquid Two-Phase Flow in an Airlift Loop Reactor

采用欧拉-欧拉两流体模型模拟了气升式环流反应器内部气液两相流动过程,考察了液相速度和气含率随表观气速的变化,液相速度和气含率模拟值的关系与两种经验关系式的计算值进行了比较,两者取得了很好的一致,证明了模型的正确性。在此基础上,使用计算流体力学模拟的方法考查了反应器内的导流筒直径和导流筒高度对反应器内两相流动的影响,导流筒直径增大,液相循环量增大,上升段气含率增大;导流筒位置升高,液相循环速度和循环量均增大,上升段气含率减小。所获得的结果对气升式反应器的设计优化具有指导意义。

Euler-Euler two equations model was applied to model the gas-liquid two-phase flow in an airlift reactor. The effect of superficial gas velocity on the liquid recirculation velocity and gas holdup were investigated. The achieved superficial liquid velocity and the gas hold up in the riser corresponded with the classical empirical correlations very well, which proved the validity of the CFD model in predicting the gasliquid two phase flow in airlift reactors. Based on this, the effect of downcomer diameter and height in the reactor were investigated, liquid circulating velocity and gas hold-up in the riser increased with draft-tube diameter. Liquid velocity increased with draft-tube height, while gas hold up in the riser decreased with it. The results achieved are valuable for the design and optimization of this kind of reactors.