提升管中气固两相流动行为的相似特性

Similarity of gas-solid two-phase flow behavior in CFB riser

在15·1m高循环流化床实验装置上对提升管内的轴向压力梯度、局部颗粒浓度和颗粒速度进行了较系统的实验测试,研究了提升管中气固两相流充分发展段在不同操作条件下流动行为的相似特性.结果表明,在(Gs/ρp)^(1·2)/Ug^(2·0)相近的操作条件下,上行气固两相流充分发展段的颗粒浓度、下降颗粒时均速度、絮状物颗粒浓度和出现频率在空间的分布特征基本相同.对于同一提升管内的同一气固两相流系统,只要表观气速和颗粒循环速率按(Gs/ρp)^(1·2)/Ug^(2·0)同步变化,不同操作条件下的上行气固两相流在充分发展段就具有相似的宏观和微观流动行为.

Hydrodynamic similarity of particle flow behavior in the fully developed region of upward gassolid CFB riser was experimentally investigated. The experiments were carried out in a 15.1 m high and 100 mm i. d. CFB riser with FCC catalyst particle, and the axial pressure gradients, local solids holdups and particle velocities were measured over a wide range of operating conditions. Through extensive analysis and comparison of particle flow behavior, it was found that the cross-sectional average solids holdups in the fully developed region changed linearly with the number group of （Gs/ρp）^1.2/Ug^2.0, although Gs and Ug showed different effects on particle flow. It was also showed that with different operating conditions, if the value of （Gs/ρp）^1.2/Ug^2.0 was the same, the local solids holdups, particle descending velocities, solids concentrations inside cluster and cluster frequencies displayed the same spatial distributions, respectively. The research indicated that the number group （Gs/ρp）^1.2/Ug^2.0 makes the effects of Gs and Ug combined, and with the same （Gs/ρsp）^1.2/Ug^2.0, the particle flow behavior in the fully developed zone of upward gassolid two-phase flow exhibited very similar micro and macro hydrodynamic characteristics.