Abstract: The pseudo-fluid model based on the closure of modified kinetic theory of granular flow was used to simulate the clustering phenomena in a circulating fluidized bed riser. The simulation results show that the clustering is a rather dynamic process. The formation of clusters reduces the slip velocity within the particle clusters, and hence some particles are lifted by air while the others fall down along the wall. The dynamic equilibrium of these two types of movements leads to the characteristic sigmoid profile of solid concentration along the axial direction.

摘要： 本文利用改进的颗粒流体动力学封闭的拟流体模型对循环流化床上升管内的颗粒团聚现象进行了模拟。模拟发现上升管内颗粒团聚物存在动态的产生、发展和消散的过程。颗粒团聚物的形成使其内部的相间滑移速度减小，从而使部分颗粒随气流上升，部分颗粒沿壁画下降。这两种运动形式的动态平衡造成了上升管内轴向浓度分布的Ｓ型曲线。