The axial flow structure in a high-density CFB riser having a height of 18 m is investigated on the basis of pressure measurements. Solids circulation rates reach 1400 kg/(m² s) at superficial gas velocities of 5–9 m/s and the apparent solids holdup exceeds 0.2, indicating high-density operations have been achieved. The apparent solids holdup increases with the solids circulation rate increasing and/or superficial gas velocity decreasing. Axial distributions of the apparent solids holdup have exponential shapes with denser regions at the bottom and more dilute regions in the upper part. The apparent slip velocity increases with the increasing solids holdup and reaches 14 m/s, showing that there are more opportunities of cluster formation in high-density operation. Furthermore, the apparent slip velocity has a power relation with the apparent solids holdup under a wide range of operating conditions.

 根据压力测量结果，研究了高度为18 m的高密度CFB立管中的轴向流动结构。在表观气体速度为5–9 m / s的情况下，固体循环速率达到1400  kg /（m ²  s）， 表观固体滞留量超过0.2，表明已实现高密度操作。随着固体循环速率的增加和/或表观气体速度的降低，表观固体滞留量增加。表观固含量的轴向分布具有指数形状，其底部区域较密，上部区域较稀。表观滑移速度随着固含量的增加而增加，达到14 m / s，表明在高密度运行中有更多的簇形成机会。此外，在广泛的工作条件下，表观滑移速度与表观固形物含量具有幂函数关系。