Abstract: Hydrodynamics and particle attrition and entrainment measurements for the spouting of fine particles were carried out in a conical-based cylindrical bed of diameter 0.186 m, inlet orifice diameters of 6 mm to 14 mm, and included cone angles of 45 to 80 degrees.Four different types of fine particles with diameter ranging from 0.241 mm to 0.874 mm were investigated. Four different flow regimes-fixed bed, stable spouting, unstable spouting and slugging were identified and mapped. Stable spouting could be achieved when the ratio of the orifice diameter to particle diameter was less than 19. The minimum spouting velocities measured were in agreement with those predicted by the Mathur-Gishler equation within ±15%. The solid density measurements obtained by a gamma ray densitometer showed that the solid density in the spout increased with bed height and that in the annulus was 3%—10% higher than in a loosely packed bed. It was observed that both particle attrition and entrainment increased with the increasing gas velocity and became smallest when stable and well-organized spouting was established.

Key words:

细颗粒, 喷动床, 流体力学, 夹带, 磨损

摘要： 在直径186 mm的喷动床中考察了细颗粒(d_p＝0.241～0.874 mm)体系的流体力学性质及夹带和磨损特性.采用不同的喷嘴直径(D_i＝6～14 mm)和锥底顶角(θ＝45°～80°)对其操作状态进行了研究，发现当D_i/d_p<19～21时可以形成稳定喷动.随着气体速度的增加，床层依次出现固定床、稳定喷动、不良喷动和腾涌等4个流动区域.实验测量的最小喷动速度与Mathur-Gishler关联式的误差在±15%之内.采用γ射线扫描仪测量了固体密度分布，结果表明喷动区的固体密度随高度的增加而增加，环流区的密度比松堆密度大3%～10%.颗粒的磨损和夹带随着气速的增大而增大，在稳定有序的喷动状态下变得最小.

关键词:

细颗粒, 喷动床, 流体力学, 夹带, 磨损