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采用离散单元法模拟了二维提升管内湿颗粒的流动和团聚特性。考虑颗粒所受重力、颗粒间(颗粒与壁面间)的碰撞力、摩擦力、液桥力以及气体对颗粒的曳力和浮力。预测提升管内湿颗粒的流动行为,得到不同含湿量下颗粒浓度和轴向速度的分布,并且定量分析了湿颗粒的团聚特性。结果显示:湿颗粒在提升管内呈现边壁浓、中心稀的环核流动结构;由于液桥力的存在,提升管内湿颗粒出现团聚现象,且颗粒以单颗粒和聚团2种方式运动;含湿量对颗粒聚团存在时间、聚团时间份额和聚团生成频率有较大的影响。
Discrete element method was used to simulate the wet particle flow and agglomeration characteristics in a two-dimensional riser. Consider the gravitational forces on the particles, the collision force between the particles (between the particles and the wall), the friction force, the fluid bridge force and the drag and buoyancy of the particles on the particles. The wet particle flow behavior in the riser was predicted, the distribution of particle concentration and axial velocity at different moisture contents was obtained, and the agglomeration characteristics of wet particles were quantitatively analyzed. The results show that the wet particles show a ring-shaped, central dilute ring-shaped flow structure in the riser. Because of the liquid bridge force, the wet particles in the tube are agglomerated, and the particles move in single particle and agglomeration. Moisture content of the particle agglomeration time, agglomeration time and agglomeration frequency have a greater impact.