Dynamic fluid bubble behaviors in the dense gas-solid fluidized bed with high densities

Abstract：Experimental measurement and numerical simulation were combined to conduct the research of dynamic flu- id bubble behaviors in the dense gas-solid fluidized bed with high densities, which is applied in the dry beneficia tion. Mean diameter of the bubbles and their rising velocity were calculated and analyzed, which have a significant in- fluence on the stable condition and uniform density distribution of the fluidized bed. The results indicate that the mean diameters among transverse and axial directions are 35 mm〈Db〈49 mm and 40 mm〈Db〈61 mm respectively,and the variation range of their rising velocity is 40 - 65 cm/s with Geldart B magnetite powder as the separation medium. Meanwhile, the density distribution keeps uniform and steady in every location of the fluidized bed and its standard de- viation is 0. 016 8. Therefore,the bubble diameter and rising velocity could be maintained to vary in an optimum and reasonable scope by adjusting the superficial gas velocity in the range of 1.5Umf -2. 2Uf. The gas-solid fluidized bed stays a sound fluidization which is favorable to coal beneficiation. The high separation efficiency of coal could be achieved on the condition. Besides, the results also indicate that the experimental and simulation approach provide an agreement in the whole calculation process.