CFD在自吸反应器气液流动和传质特性研究中的应用

针对配置气体分布器的六叶轮自吸反应器建立了欧拉气液两相流三维瞬态模型,耦合Higbie气液传质模型,采用CFX软件对其气液混合过程的流场、气含率、吸气速率及溶氧传递过程进行数值模拟,获得了反应器的流动特性、气液分散性能、吸气特性及气液传质特性.分析了反应器内水平及竖直位置上的流型特征及溶氧传递性能,结合实验数据及经验关联式对比分析了对气含率及吸气速率的预测作用.结果表明,六叶轮转子及其配置的气体分布器可以获得较均匀的气液混合,气含率及吸气速率的预测与实验值偏差分别为5.2% 和17.6%,模拟发现在反应器底部近壁处溶氧及混合效果不佳.

Gas-liquid flow and mass transfer characteristics of gas-inducing reactor with CFD simulation

By coupling Higbie gas-liquid mass transfer model, Euler three-dimensional transient gas-liquid flow model was established for a six impeller self-inducing reactor with gas distributor. The model was used to simulate the flow field, gas holdup, gas-inducing rate and dissolved oxygen transfer of the gas-liquid mixing process with CFX software. The flow characteristics of the reactor, gas-liquid dispersion performance, gas induction and gas-liquid mass transfer properties were obtained. The analysis on flow pattern characteristics and dissolved oxygen transfer performance at horizontal and vertical positions of the reactor were made, comparing and analyzing the prediction of gas holdup and gas-inducing rate based on experimental data and empirical correlations. Six impeller rotor and gas distributor could obtain uniform gas-liquid mixing. Deviations of gas hold-up and gas-inducing rate predictions from experimental values were 5.2% and 17.6% respectively. Dissolved oxygen transfer and mixing performance near the wall at the bottom of the reactor was bad.