| The spouted bed was originally used for drying process for large particles as a branch of fluidization technology. With the development of technology, the application of spouted bed has been developed to the surface coating, drying, crushing, granulation, coal combustion, gasification, pyrolysis and thermal cracking. Both the experimental study and numerical simulation are important methods to explore the inherent law of gas-solid flow in bed.In this paper, the movement of particles was tested by cold state test bed in different conditions, and the velocity data of the particles was obtained by the MatPIV program. The influence of superficial velocity and particle size on the flow characteristic was discussed. The results show that with the increase of the superficial velocity, the height of particles is gradually improved. With the increase of the particle diameter, the velocity of particles has a decreased trend and the height of particles is gradually reduced. The unsteady flow phenomenon in the spouted bed was also studied, and it is found that the jet flow shifts to the bubble.And DEM coupled with CFD has been used to simulate spouted bed with different nozzles. Solid particles are simulated based on the soft sphere model in this work. The gas phase is solved using SIMPLER approach. The coupling between the gas phase and the particles is based on Newton third law. The circulation mechanism of particles was studied from the microcosmic aspect, the information of the fluidization process, the particle velocity field, the gas velocity field and the particle volume fraction was analyzed. It’s found that the generation of bubbles and the motion of particles are similar by comparing simulation with experimental results. The velocity distribution of particles is also consistent. The result indicates that the core-annular flow pattern can be discovered by the self-developed CFD-DEM program, and the precision of numerical simulation and the accuracy of model and parameters are verified. |
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