在实验基础上,采用欧拉双流体模型对矩形错流移动床中稠密气固两相流动进行了模拟,分析了矩形错流移动床的空腔、贴壁、两相速度、气相停留时间、压降等.结果表明,气固两相流动受端部效应影响.随表观气速增大,贴壁(约0.19m/s)和空腔(约0.31m/s)现象出现.空腔随时间发生变化,而贴壁为渐进型,气速与空腔和贴壁的形状有关.气速分布、空腔和贴壁使压降沿轴向呈反C形分布.进料影响区、主体流动区和下料影响区压降比约为6:10:9.随表观气速增大,气相停留时间减小,空腔尺寸增大,贴壁厚度先增大后不变,压降增大;而颗粒循环强度的影响不大.
Based on the experimental result, Eulerian two-fluid model was used to investigate the cavity, pinning, flow streamlines, gas residence time and pressure distribution in a rectangular cross-flow moving bed. The results showed that the gas-solid two-phase flow was influenced by the end-effect. As the superficial gas velocity increased to about 0.19 and 0.31 m/s, the pinning and cavity appeared respectively. The cavity changed with time, while the pinning was virtually progressive. The shapes of both the cavity and pinning were determined greatly by the superficial gas velocity. The gas velocity distribution, cavity and pinning led to the pressure distribution profile in the shape of reverse C. The pressure drop ratio of the feed influencing zone to the gas-solid contact zone and discharge influencing zone was about 6:10:9. With increasing of the superficial gas velocity, the gas residence time decreased, both the cavity size and pressure drop increased, while the pinning thickness increased first and then remained almost unchanged. But the solids flux had little effect on the investigated oarameters.