不等粒径流化床中鼓泡行为的研究

Study on Bubbling Behavior with Unequal Particle Diameters in Fluidized Beds

用颗粒轨道模型的软球方法模拟了不等粒径流化床中的鼓泡行为。分别讨论了表观气速、恢复系数、分布板结构、床宽与床高之比、粒径分布对流化床中鼓泡行为的影响。研究结果表明:随表观气速的增加,鼓泡形成、上升、破裂的速度加快,且表观气速太大或太小都不利于鼓泡的形成;恢复系数以及分布板上孔的个数对鼓泡行为都有显著影响;床宽与床高之比较小时,在流化床中形成节涌现象,且床宽与床高比越小,节涌现象越明显;粒径分布对鼓泡行为无较大影响。

Bubbling behaviors in the fluidized beds by soft-sphere method of the particle-motion-resolved discrete model were simulated. The influences of gas superficial velocity,restitution coefficient ,structure of distributor, ratio of bed width and height, and distribution of particle diameters on the bubbling behaviors were studied. Numerical results indicate that the processes of bubble formation,rising and breaking are accelerated as the gas superficial velocity increasing. If the gas superficial velocity is too fast or too slow,the bubbling behaviors will be weakened. Restitution coefficient and structure of distributor have distinct influences on the bubbling behaviors. When the ratio of bed width and height is small ,slugging phenomena will appear in fluidized beds. The smaller ratio of bed width and height,the more apparent of slugging phenomena. The distribution of particle diameters has little influence on the bubbling behaviors.