Effect of Fluidizing Gas Humidity on Bubble Behaviors in a Gas-Solid Fluidized Bed under Vibrating Conditions

摘要

Effect of the fluidizing gas humidity on bubble behaviors was examined in a two-dimensional fluidized bed under vibrating conditions. Vertical and horizontal vibrations were added to the fluidized bed. The humidity of fluidizing gas was controlledbetween 40 to 90 %. The frequency and the amplitude of vibration were set 14.8 - 29.8 Hz and 1.5 - 6.0 mm, respectively. Particle used in this study were spherical glass beads and their mean diameters were 43LL m which belonging to the Geldart group A. As the humidity of fluidizing gas increased, the bubble rising velocity increased, while the bubble diameter became smaller. On the other hand, the aspect ratio of rising bubble became higher as the gas humidity increased. The increscent tendency of bubble rising velocity with the gas humidity is interrelated with the change of bubble shape under the high gas humidity conditions. When the horizontal vibration was added to the bed, the effect of gas humidity on the bubble behavior was not significant, which indicated the horizontal vibration prevented the elongation of bubbles shape due to the gas humidity. On the other hand, for vertical vibration, the bubbles were elongated at the lower gas humidity comparing with non-vibrated condition. From these phenomena, it was clarified that the vibration direction had a significant different influence on the bubble behaviors under high gas humidity conditions.