【摘要】 采用直接模拟MonteCarlo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、浓度以及聚团流动进行分析.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,模拟结果与文献的实验结果基本吻合.更多还原

【Abstract】 A discrete particle motion-collision decoupled model based on dense gas molecular dynamics and gas-solid two-phase fluid dynamics of dense gas-solid flow in the fluidized bed was developed. Particle collision was modeled by means of the direct simulation Monte Carlo (DSMC) method.The large eddy simulation(LES) accounting for the effect of particle fluctuation was used to model gas turbulent flow. The Newtonian equations of motion were solved for each individual particle in the system. The interaction between gas phase and particle phase was determined by means of Newtonian third law. The flow behavior of gas and particle phases were numerically simulated in a circulating fluidized bed. The distributions of gas and particle velocity and particle concentration in the riser were analyzed.The number-averaged duration time, the ratio of total cluster duration time to total observation time and the cluster frequency were obtained in the circulating fluidized bed. The simulated results were in agreement with experimental measurements of literatures in the circulating fluidized beds.更多还原