超重力旋转填充床氧解吸过程的数值模拟

摘要

A mathematical model for gas-liquid interphase mass transfer was established based on the visual study of fluid flow in a rotating packed bed (RPB). The effects of model parameters on liquid mass transfer coefficient kL, as well as the effect of operation parameters on overall volumetric mass transfer coefficientKLa in gas-liquid mass transfer process of water deoxygenation by a nitrogen stream were studiedvia numerical simulations with the mathematical model. Simulation results indicated thatkL increased with decreasing liquid residence time and increasing liquid molecular diffusivity.KLa increased with increasing higee (high gravity) factor, temperature and liquid flow rate but influenced hardly by pressure, and decreased slightly with increasing gas flow rate. Additionally, the mass transfer contribution of cavity zone diminished with increasing higee factor, as well as decreasing cavity zone volume. According to numerical simulation results, the nature of process intensification for gas-liquid mass transfer process in RPB lay in transient liquid residence time. Deoxygenation efficiencyE calculated from this model agreed well with experimentalE extracted from literatures with deviations within ±16%, which verified the mass transfer model.%基于旋转填充床流体流动的可视化结果，建立了超重力旋转填充床气液传质过程的数学模型，模拟氮气解吸水中溶解氧的传质过程。模拟结果表明，缩短液相停留时间、提高液相扩散系数都能增大液相传质分系数kL；总体积传质系数KLa随超重力因子的增加而增大、随温度的上升而增大、随气相流率的增加略有下降、随液相流率的增加明显增大；空腔区传质贡献率随空腔区的增大而增大，随超重力因子的增大而减小；且短暂的停留时间是超重力旋转填充床对传质过程强化的本质原因。模型较好地符合文献的实验数据，误差在±16%以内。