气固逆流下行流化床中颗粒速度的径向与轴向分布

在内径90 mm、高7 m的逆流下行床冷态实验装置中，研究了气固逆流下行床中循环锅炉灰(dp=300 mm)颗粒速度的径向分布及其沿轴向发展. 结果表明，局部颗粒速度沿径向分布是不均匀的，在完全发展区，颗粒速度中心和边壁低、在r/R=0.85附近颗粒速度最大. 由大量实验数据回归出预测充分发展段局部颗粒速度的关联式，该公式计算值与实验值的平均相对偏差小于±11%. 不同径向位置的局部颗粒速度沿轴向的变化趋势不同，边壁区域(r/R>0.622)颗粒速度沿轴向单调递增，而中心区域(0

Radial and Axial Distributions of Particle Velocity in a Counter-current Fluidized Bed

Experiments were carried out in a 90 mm i.d.,7 m high gas upflow and solid downflow fluidized with circulating boiler ash(dp-300 μm) to measure the radial profiles of particle velocity and concentration,and its axial development.The results show that particle velocity is lower both in the center and near the wall in the fully developed region.The maximum particle velocity exists at around r/R<0.85.An empirical formula of particle velocity in the developed region is derived from a number of experimental data.Relative errors between calculated values and experiential data are less than ±11%.Local particle velocity in the region near the bed wall(r/R<0.622) increases along the column.While local particle velocity in the central region(0