大颗粒流化床中颗粒受力的数值模拟  

Numerical Simulation for Forces Exerted to Coarse Granules in Fluidized Bed

作　　者：李晓光[1] 徐德龙[1] 范海宏[1] 

机构地区：[1]西安建筑科技大学材料科学与工程学院

出　　处：《西安交通大学学报》2006年第7期836-840,共5页Journal of Xi'an Jiaotong University

基　　金：国家自然科学基金重点资助项目(50432040);国家自然科学基金资助项目(50272050)

摘　　要：通过数值计算模拟了大颗粒鼓泡流化床中颗粒的受力情况．在模拟过程中，气相采用了欧拉描述方法，颗粒相运动过程的模拟采用了离散单元法．利用软球模型模化颗粒之间的碰撞力，分别研究了3种流化数下温度为300K、内含11000个直径3mm颗粒的流化床中，瞬间颗粒受力在床内的分布情况．结果表明：在通常情况下，乳化相区域颗粒受到的气体曳力平均值一般是其自身重力的1～2倍；除气泡内部外，颗粒所受到的碰撞力亦高于颗粒自身的重力；流化数越高，则床内碰撞力越大，当流化数为1．67后，碰撞力已成为影响床内颗粒无规则运动的主要因素．In a gas-solid fluidized bed operated at 300 K with 11,000 spherical partieles ot 3 mm diameter, the instantaneous distribution of the forces exerted to coarse granules was simulated, where the Euler description was adopted for gas phase and the discrete element method for particle phase, and the soft sphere model was used to treat collision force among granules. It is shown that the particles drag force due to gas phase in the emulsion region is 1-2 times greater than particle gravity force, and the collision force exerted to granules except inner region of bubbles is greater than particle gravity force as well under three different fluidization numbers. As fluidization number increases, the collision forces are enhanced. As fluidization number reaches beyond 1.67, the collision forces become the predominant factor governing particle behaviors.

关 键 词：数值模拟 流化床 大颗粒 流化数 碰撞力 

分 类 号：TQ051.13[化学工程]