湿颗粒体系的流态化行为及机理研究

项目名称： 湿颗粒体系的流态化行为及机理研究

项目编号： No.51306035

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 能源与动力工程

项目作者： 刘道银

作者单位： 东南大学

项目金额： 26万元

中文摘要： 湿颗粒流态化存在于多种流化床物理和化学工艺过程中，而流态化学科经过半个多世纪的发展，主要针对干燥颗粒体系，对于湿颗粒流态化的认识远未成熟。为此，本项目提炼出湿颗粒流态化基础问题，开展专题研究。结合微观层面的湿颗粒碰撞和宏观层面的湿颗粒体系流化，逐层推进研究。颗粒层面上，采用横向风实现颗粒与含液膜覆盖的平板的斜向碰撞实验方法，同时研究湿颗粒法向和切向碰撞能量耗损，弥补了现有研究局限于法向碰撞的缺点，为湿颗粒碰撞模型的建立提供全面的数据；颗粒体系层面上，基于湿颗粒流化床的床层压力波动和瞬时流化形态分析，揭示湿颗粒流化形态的转变规律。进一步，基于Stokes无量纲数耦合液桥力与接触力，建立湿颗粒碰撞模型，发展湿颗粒体系DEM模型。再根据DEM模拟结果获取湿颗粒流化床的瞬时和细观结构，建立"颗粒碰撞-气泡等介观特征-流化形态"不同尺度间的关联，深入揭示湿颗粒流态化的机理。

中文关键词： 湿颗粒；流化床；恢复系数；CFD-DEM模型；

英文摘要： Liquid addition is common in industrial fluidization-based processes， however, most studies on fluidization have focused on dry system. The influence of liquid on fluidized beds is almost an open problem. Therefore, in the present project we will focuse on the characteristics and mechanisms of fluidization of wet particles. Both micro behaviros of particle collision with the presence of liquid and macro behaviors of wet partlcie fluidization are studied. On the particle collision, the effect of liquid content on energy dissipation of particle collision both in the normal and tangential directions are investigated, while in the literaute studies are limited to normal collision. The comprehensive collision data will provide a solid base for developing wet particle collision model. On the macro fluidization behaviors of wet particles, systematic tests are performed in a fluidized bed to clarify transition among different flow patterns by analyzing pressure fluctuations and instantaneous fluidization images. In addition, numerical simulations are carried out. By analyzing wet particle collision using Stokes non-dimensional number, the contacting force and liquid bridge force are coupled to build a novel contact force model of wet particle collision. The collision model is then coupled with discrete element method (

英文关键词： wet particles；fluidized bed；restitution coefficient；CFD-DEM；