摘要
气固两相流中尤其是稠密气固两相流中颗粒浓度在空间的分布总是非均匀,局部颗粒聚集。该文直接以颗粒团为研究对象,采用颗粒团离散单元方法(DEM),建立非球形颗粒团的运动碰撞的模型与算法,基于真实碰撞,跟踪每个颗粒团的运动,模拟3种均匀或非均匀流场内的颗粒团运动经历。计算结果展现了颗粒浓度非均匀局部聚集的过程,揭示不同工况下流场中颗粒团的大小,颗粒分布及局部颗粒聚集的规律,结果表明在均匀流场中,颗粒均匀密集,非均匀流场中,颗粒浓度的非均匀性加剧。所得计算结果合理,与前人的模拟结果及实验结果相符。同时计算表明,采用颗粒团DEM模型能真实地揭示稠密气固两相流的特性,并使计算量有效减少。
Particle interactions result in non-uniform distribution of the particle in a flow field especially in dense particle-gas two-phase flow, and most particles are congregated as clusters. The particle cluster is directly treated as one discrete phase, the cluster discrete element method （DEM） including calculation expression of the cluster instant size, cluster motion and collision models and the corresponding algorithm are established, thus the real motion and collision process of each particle cluster in a flow field are described. This method is used to numerically study three types of two-phase flow, and detailed results regarding the cluster motion, reforming and the dense two-phase flow characteristic in different flow t-fled are obtained. The developing process of non-uniformity of particle distribution is visualized. Detailed information of the cluster formation, cluster distribution and size are obtained. Calculated results show that in uniform gas flow filed, particle evenly congregates; while in non-uniform gas flow filed, non-uniformity of particle distribution intensifies. These results are reasonable and are agreement with previous experimental and calculating ones. It shows the cluster DEM model can reveal the dense two-phase flow characteristic in deed, and the computational memory and computational time are effectively reduced.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2007年第20期18-23,共6页
Proceedings of the CSEE
基金
国家自然科学基金项目(50406025)~~
关键词
非均匀
颗粒浓度
颗粒团蓠散单元方法
稠密气
固两相流
non-uniformity
particle distribution
cluster discrete element method
dense two-phase flow
