中文摘要：

采用直接模拟蒙特卡罗方法（DSMC）模拟颗粒间的碰撞，采用考虑颗粒脉动流动对气相湍流流动影响的大涡模拟（LES）研究气相湍流。单颗粒运动满足牛顿第二定律，颗粒相和气相相间作用的双向耦合由牛顿第三定律确定。数值模拟垂直管内气固两相上升流动，对管内气相速度和颗粒相速度、浓度以及聚团的流动特性进行分析。研究平均单个颗粒团聚物的存在时间、颗粒团聚物的时间份额和颗粒团聚物的生成频率分布特性，模拟结果与Manyele等（2002）和Sharma等（2000）试验结果吻合。

英文摘要：

Particle collision is modelled by means of direct simulation Monte Carlo （DSMC） method. The large eddy simulation （LES） is used to model gas turbulence. The Newtonian equations of motion are solved for each simulated particle in the system. The interaction between gas phase and simulated particle is determined by means of Newtonian third law. The flow behaviors of gas and particles phases are numerically simulated in a riser. The distributions of gas and particle velocity and particle concentration in the risers are analyzed. The duration time, averaged solid concentration in cluster, the ratio of total cluster duration time to total observation time and the cluster frequency are obtained in the circulating fluidized bed. The simulated results are in agreement with experimental measurements by Manyele （2002） and Sharma （2000）.