Numerical Simulation Of Fluidization Characteristics Of Nanoparticles In Micro-scale Magnetic Fluidized Beds

Because of the small dimension of micro-scale fluidized beds (MFBs), they arenot only characterized excellent heat and mass transfer efficiency but also the energyconsumption and waste effluent is decreased greatly. With the intensification ofmagnetic field, the effect of reaction, heat and mass transfer rates in MFBs areincreased significantly. It can be used as catalytic and none catalytic reactors. Thefluidization properties are valuable for theoretical investigations and industrialapplications in MFBs.The software Gambit2.2and Fluent6.3are used in this topic, to study thefluidized process in micro-scale fluidized beds in the system. The effects of innerdiameters, gas properties, particles, the perforated ratio and structure of distributors,magnetic field strength and micro-scale fluidized beds with auxiliary side intakes areexamined, respectively. The channeling, inter-circulation, wall effect and bed pressuredrop are discussed. The results showed that the particles began fluidizing with theincrease of gas velocity. When the gas velocity is0.20m/s, the nanoparticles isconveyed out of micro-scale fluidized beds. During the process, the range of gasvelocity is little. The kinds of uneven air inlet fluidized bed are designed to solve thephenomenon of gas-solid phase distributing non-uniform and the particles along thewall rising. The radial flow of the bed has greatly improved. As the perforated ratio ofdistributors increases, the volume of the bubble is gradually increased. At the bottomof the fluidized bed, the large bubbles are formed. With the increase of fluidized beddiameter, wall effect weakened gradually, and the fluidized quality of particles improve.In the micro-scale fluidized beds with auxiliary side intakes, vortices formed are betterand partical internal circulation in the bed was more implemented. Nanoparticles fullymake contact with the gas. The hydrodynamic behavior of nanoparticles in a magnetic assisted MFBs with of20mm inner diameters, are investigated at various intensification of magnetic field.Channeling can be suppressed in the magnetic field to carry out stable fluidization. Thedistribution of velocity and volume fraction of nanoparticles and particle granulartemperature are analyzed at various intensification of magnetic field. The results showthat velocity of nanoparticles and particle granular temperature are decreased with theincrease of the magnetic-flux density.