磁流化床铁磁颗粒的流化特性与磁稳区的确定(英文)

Fluidization characteristics of magnetic particles and determination of stable fluidization zone in magnetically fluidized bed

针对磁流化床可实现磁稳流化的特点，提出了一种确定和计算磁稳流化区域的方法．通过对4种不同粒径的铁磁颗粒（其平均粒径范围231—512μm）进行流态化实验研究，得到铁磁颗粒分别在磁场强度为0—7330A／m时的流化曲线．实验中采用压降波动的方法测定最小鼓泡流化速度，进而确定磁稳流化区域的范围．基于铁磁颗粒的流化曲线，分析得到铁磁颗粒的流化特性，讨论了颗粒粒径、磁场强度对磁稳流化区域的影响；运用多元回归的方法得到磁稳流化区域与磁重势能比、阿基米德数以及雷诺数之间的实验关联式．与已有的研究相比，此式较为简单，具有较好的适用性，据此式可以方便地给出磁流化床磁稳流化状态运行时的合理参数．

To determine and calculate the stable fluidization zone in a magnetically fluidized bed, the fluidization characteristics of magnetic particles are investigated. Four kinds of magnetic particles with different average diameters, ranging from 231 to 512 μm, are fluidized in the presence of magnetic fields with specified values of the intensity in the range of zero to 7330 A/m, and the particle fluidization curves are plotted. For marking the stable fluidization zone in the curves, the minimum bubbling velocities of particles are measured by the pressure-drop fluctuation. Based on the fluidization curves, the influences of the average particle diameter and magnetic field intensity on the zone are analyzed and discussed. A correlation to determine the stable fluidization zone is derived from the experimental data, using three dimensionless numbers, i. e., the ratio of magnetic potential to gravity potential, the Reynolds number and the Archimedes number. Compared with available data reported, it is shown that the correlation is more simplified to predict relative parameters for the bed operating in the state of stable fluidization under reasonable conditions.