(238a) Spouting Phenomenon of Powder through a Small Orifice at the Bottom of Vessel Using the Fluidization and Aeration

We experimentally investigate the spouting phenomenon of powder through a small orifice at the bottom of vessel using the fluidization and aeration for powder bed of glass beads where the particle diameter is 58μm and the particle true density is 2523kg/m3. Experimental apparatus has the part of powder bed and supplying air where the inside diameter and the height of powder bed are 50mm and 150mm, respectively. The air is supply from the upper and lower of powder bed. As the experimental condition, the flow rate of air from both of them is changed from 4 to 10L/min. The fluidized and aerated powder bed in the present study can smooth discharge from the circular nozzle at the bottom of vessel where the nozzle diameters are 1 and 2mm. We measure the discharged mass of powder from the circular nozzle and the interstitial air pressure at the bottom of powder bed. The results showed that the powder is stable discharged from the circular orifice when the same volumetric flow rate of air is injected from the upper and the lower of the powder bed. Its tendency showed that the mass flow rate of powder and the interstitial pressure at the bottom increases with increasing the flow rate of air. Then, the mass flow rate of powder increases in straight line with an increase in the flow rate of air. Further, it has been understood that the interstitial pressure increases in the small orifice. On the other hand, the powder flow through an orifice shows the increased in residual powder and the instable discharge of powder in the vessel when the air is only supply from upper or lower of powder bed.