【摘要】 针对磁流化床中颗粒浓度高,相互作用强的特点,在双流体模型的基础上,引入颗粒流的动力学理论,对床内铁磁颗粒在不同工况下的流化特性进行数值模拟.计算结果表明:在无磁场或弱磁场作用下,床内多处产生气泡,颗粒呈鼓泡流化状态;在适度磁场作用下,磁场对颗粒的作用明显,可以抑制床内气泡生成,实现颗粒的稳定流化.增大气体表观流速比后,磁场的调节作用相对减弱,颗粒不能实现稳定流化.与试验数据比对,二者吻合较好,数值模拟结果较好地反映磁流化床中颗粒的流化行为.更多还原

【Abstract】 Based on two-fluid model and kinetic theory of granular flow,numerical simulations were carried out to investigate fluidization behaviors of ferromagnetic particles in magnetically fluidized bed(MFB) characterized by high granular concentration and strong interactions among particles.The nume-rical results indicate that under no or weak magnetic field particles assume bubbling fluidization due to the bubbles occurring in the bed;under moderate magnetic field,particles assume stable fluidization by restraining bubbles formation due to the enhancing effect of magnetic field.However,when the ratio of superficial gas velocity increases further,particles cannot assume stable fluidization since the magnetic forces exerted on particles are not dominant any more to assume bubbles forming in the bed.The numerical results agree well with the experimental data,reflecting the fluidization behavior of ferromagnetic particles in MFB in a large extent.更多还原