磁流化床稳定性分析

应用Foscolo的颗粒床模型分析了磁流化床稳定性,得到了磁流化床的稳定判据;根据得到的判据分别对层流和湍流情况分析了磁场对磁流化床稳定性的影响。

STABILITY OF MAGNETICALLY FLUIDIZED BED

In order to predict the changes in magnetically fluidized bed from aggregate fluidization to par-ticulate fluidizaion, or vice versa, the criteria of magnetically stabilized fluidized bed are formulated, which are different from Rosensweig' s criteria and avoid some difficulties from Rosensweig' s method. The criteria are based on Foscolo' s "particle bed model", which is derived from a fluid dynamic mechanism for particle - particle force transmission and hypothesizes particles chained with each other in the fluidized bed. This hypothesis is very well adapted to particles in magnetically fluidized bed. By following Foscolo's model and considering magnetic field on particles, the criteria can describe the stability of magnetically fluidized bed. The stability diagrams from the criteria agree with Cocker' s experimental data. The results prove that Foscolo' s "particle bed model" is also applicable magnetically fluidized bed. According to the criteria, the effect of magnetic field is analysed on the stability of magnetically fluidized bed in both the laminar and turbulent flow regime. Comparing the criteria we proposed with Fos-cole's criteria of fluidized bed, we fined that magnetic field is conducive to increasing the stability of magnetically fluidized bed.