上行气固两相流充分发展段的颗粒浓度

在Ф100mm× 16m循环床提升管实验装置上测试了134组操作条件下提升管 12个截面位置的平均颗粒浓度 ,其中 113组操作条件下提升管中的气固两相流展现出明确的充分发展段 .结果表明 ,充分发展段的颗粒浓度εs 随颗粒循环量G_s 的增加而增大且具有显著的线性关系 ,ε_s 随表观气速U_g 的增加以幂函数关系减小 .所提出的实验关联式不仅较好地拟合了本文所获得的充分发展段的平均颗粒浓度数据 ,而且诠释了以往有关提升管稀相段出口颗粒浓度预测结果之间的差异 ,更明确地反映了充分发展段颗粒浓度与操作参数之间的定量关系

SOLIDS HOLDUPS OF GAS-SOLID TWO-PHASE UPWARD FLOW IN FULLY DEVELOPED REGION OF CFB RISER

Systematic experiments were conducted with FCC particles in a 16m high CFB riser to investigate the solids holdup in a fully developed section of the riser,with superficial gas velocity U _g from 2.0 to 10.3m·s ^-1 and solids circulating rate G _s from 5.4 to 230kg·m ^-2 ·s ^-1 .Of 134 sets of operation conditions employed in the experiments,there were 113 sets of operation conditions under which the gas-solids two-phase flow became fully developed in the upper or even the whole section of the riser.It is found that in a fully developed section of the riser,the average solids holdup ε _s increases linearly with increasing solids circulating rate G _s and decreases with increasing superficial gas velocity U _g,with a trend rather different from that reported in literature.The correlation developed in the paper,for solids holdup in a fully developed section of CFB riser,is in good agreement with the experimental data and also explains the differences among the predicted results of other authors,delineating more clearly the variations of solids holdup in a fully developed section with operation parameters.