Identification of flow regimes and determination of the boundaries for magnetized fluidized bed with Geldart-B particles

Abstract

The magnetized fluidized bed (MFB) with Geldart-B particles exhibits many distinct flow regimes depending on the magnetic field intensity (H) and gas velocity (Ug). The identification of these regimes was reviewed for the MFB with magnetizable particles and that with binary admixture of magnetizable and nonmagnetizable particles. Meanwhile, methods for determining the boundaries between two adjacent flow regimes were clarified. The MFB state was found to depend not only on H and Ug but also on their application sequence (i.e., operation mode) within certain operating zones. The dependence feature arose from that the MFB therein could have different equilibrium states for the same combination of H and Ug. Furthermore, such a polymorphic characteristic of the MFB was revealed to result from the internal friction among the particles that were in unfluidized/packed state. Many of the MFB states were demonstrated to be in metastable equilibrium. Nevertheless, they differed significantly from the metastates well-known in the discipline of physical chemistry, such as supercooling and superheated. In fact, they belonged to the amorphous/glass state. This review will deepen our hydrodynamic understanding of the MFB and further promote its commercial application in the chemical and biochemical industries.