振动场中纳米颗粒聚团大小研究

he fluidization behavior of SiO2 nano-particles and the effects of fluidization time, superficial gas velocity, ratio of height to diameter and vibration parameters on size of agglomerates have been systematically investigated in a bed of 40mm in diameter. Agglomeration and disagglomeration mechanism of cohesive nano-particles have been discussed. Based on these experimental results slugging and channeling of bed disappeared, the minimum fluidization velocity is reduced, the measured agglomerate size is decreased and fluidization quality was significantly improved due to introduction of vibration energy. Compared with vibration amplitude, vibration frequency has a comparatively significant effect on agglomerates’ size. The size of agglomerates appeared changing regularly and reached maximum, then decreased with increasing frequency. In addition, the agglomerate size decreased with increasing gas velocity since a higher gas velocity therefore tends to enhance collision between particles and/or agglomerates, which may in parallel result in a smaller agglomerate size. The vibrated fluidized bed should be operated with a shallow bed to maximize dispersion and fragmentation of agglomerate.