Abstract：A gas-solid acoustic fluidized bed, which is 0.16 m in diameter and 1.8 m in height, was employed to investigate systematically the effects of sound assistance on the instantaneous particle concentration profile, the variation of sound energy in different flow regimes and axial positions, the effect of sound pressure level (SPL) on the minimum fluidization velocity (Umf) and granular temperature with air as gas phase and ultrafine SiO2 particles as solid phases. The developed model concerning the sound assistance was coupled with conventional momentum equation in computational fluid dynamics software Fluent 6.2 to simulate hydrodynamics. The research results showed that the instantaneous particle concentration distribution in the dense phase region was a parabolic profile. The axial particle concentration was increased and the bubble size was decreased as the sound assistance was introduced into the fluidized bed. The sound energy increased significantly as the gas velocity increased. The threshold point of the gas velocity 0.05 m/s indicated the transition of flow regime from the fixed bed to fluidized bed. The sound energy at the middle region of bed was larger than that at top and bottom regions. Umf increased significantly with increasing particle diameter. The granular temperature increased with increasing sound pressure level, which showed that the frequency of bubble coalescence and breakup are increased.
Yang Hui,Cao Changqing. Fluid Dynamics of Ultrafine Particles in a Gas-Solid Fluidized Bed Coupling with Acoustic Field[J]. 化学反应工程与工艺, 2013, 29(4): 338-343.
