Study On Flow Charactericstic Of Gas-solid Two-phase And Performance Cyclone Separator Used In CFBB

Circulating fluidized bed boiler(CFB) is a kind of technology which is fuel adaptable broadly and clean-burning. Because of those characteristics, CFB had been rapid developed in the past decade years in world wildly. As its core component, cyclone separator's performance plays a deep role in the operation of CFB boiler.The separating efficiency of cyclone separator is closely related to the flow field inside. It is significant for optimizing the structural and separating efficency of cyclone separator that studying the gas-solid two-phase flow characteristics deeply. The method which combines the experimental study and numerical simulation has used in this dissertation. It has been analyzed in this dissertation such as gas flow field, gas-solid flow field and concentration field. It has been simulated that the pressure drop and separating efficiency of cyclone separator at different inlet velocity and inlet height-width aspect ratio. And on this basis, a structure-ameliorated cyclone separator has been brought forward.(1) Through comparation and analysis, the velocity distribution and pressure distribution simulated by RSM model (Reynolds Stress Model) fit the results of experiment well. The results of CFD can predict the internal flow field of separator well.(2) Particle stochastic trajectory model has been used to simulate the particle phase. The motion of particle and particle concentration in the cyclone separator has been analyzed. Based on those analysis, the short-circuit flow, upper dust rin and re-entrainment are predicted and the grain size efficiency and separating efficiency are obtained.(3) It has been simulated that the pressure, grain size efficiency and separating efficiency at different inlet velocity. It has been analyzed that the influence of performance at different inlet velocity.(4) It has been simulated that the pressure, grain size efficiency and separating efficiency with different inlet height-width aspect ratio. The result shows that there is proper inlet height-width aspect ratio which can make the cyclone display the best performance.(5) Based on the analysis of inlet velocity and the inlet section height-width ratio, a structural developed cyclone separator has been raised. The simulating result shows that the separating performance of the new separator has been improved greatly compared with the common style.