湿颗粒流化床流动特性的实验研究

In the present work, a visual wet granular fluidized bed setup is established. Fluidization characteristics of various Geldart-D particles with different liquid contents are investigated in this experimental system, containing flow pattern, pressure drop and minimum fluidization velocity. Some notable conclusions can be obtained from the experimental results. 1) In the wet fluidized bed, agglomeration behavior for wet particles and bubbles with irregular shapes can be observed apparently. Meanwhile, the stability of wet granular flow process is lower than that of dry granular bed. In the region near the wall, local channeling is easy to happen. 2) At the stage of fixed bed, bed pressure drop for wet particles is smaller than that for dry particles due to the increases of voidage: Based on the Ergun formula, the calculating method of pressure drop for wet granules fixed bed is proposed. 3) The minimum fluidization velocity U_mf for wet granular is higher than that for dry particles. The U_mf for wet particle increases with the increase of particle size d_p. A semi-empirical correlation, Re_mf = 0.279 · Ar^0.5, is developed to predict the U_mf of the wet particles. The predictions calculated by this correlation agree well with the present experimental results with the error of less than 15%.