Experimental Study And Numerical Simulation Of Particle Motion In Vibrated Fluidized BED

Vibrated fluidized bed is mechanical vibration energy added to the fluidized bed, vibration can reduce the pressure loss, initial flow in bed, increase bed uniformity and stability, and the vibrated fluidized equipment is a kind of equipment with high efficiency of heat and mass transfer characteristics, so it is widely used in drying, spray granulation and separation and other industrial processes. With the continuous development of CFD, the theoretical analysis and calculation with the numerical method is more and more shows great potential development, the study of multiphase flow play an important role. In this paper, by using the CFD numerical simulation method, using fluid mechanics simulation software Fluent, write vibrated grid UDF program, the fluid characteristics of vibrated fluidized bed was simulated. By comparing the numerical simulation results and experimental results, to provide detailed and reliable data to support and theoretical guidance for the design and development of reactor and the optimization of process operation, and improve the efficiency of the reaction.(1) Reviewed the research progress in many aspects of experimental and numerical simulation studies in vibrated fluidized bed. The Euler method is one of the earliest methods applied to the simulation of the fluidized bed, but the Euler model without considering the particle size, shape, collision and other microscopic characteristics, compared with the DEM model is more suitable for study vibrated fluidized bed, and DEM model required fewer experience parameters. But because of complex DEM models will consume a large amount of computing time, previous literature only for two-dimensional vibrated fluidized bed or pseudo two-dimensional vibrated fluidized bed, only for small quantity of particles, and can not accurately calculated vibrated fluidized bed operating characteristics. These problems have become the reason of this research work.(2) The two-dimensional vibrated fluidized bed was studied by experiment and numerical simulation, experimental study on the the bed pressure drop of vibrated fluidized bed, and use Eulerian model, simulated the influence of the vibration direction, solid content, particle velocity. Experimental study show that the vibration can enhance the mobility of particles, the bed pressure drop is more close to the theoretical value. Numerical simulation of vertical vibration to find the bed bottom forming low particle concentration region, the vibration gaps and large bubbles are produced, and level of the bed side wall forming vibration gap; vibration intensity increases the fluidization effect, the vibration frequency increases the fluidization effect but no effect when the vibration frequency is especially large.(3) The CFD numerical simulation method combined with the DEM model, breakthrough two-dimensional particle simulation, established a 3D model of the magnitude of the 100000 particles. Simulation of 3D vibrated fluidized bed can calculate particle collision model in all directions, more realistic prediction of the distribution characteristics of fluid flow and particles, with the continuous development of computer technology, particle simulation time is reduced, the 3D model of the 100000 particles can calculate faster. Study effect of vibration on the solid content, particle velocity, bed voidage.