Abstract
Local behavior of gas and particles in a three-dimensional jetting fluidized bed grid zone was investigated. A cone-shaped distributor with a center nozzle was employed as a gas injector and the results were compared with those for a flat distributor. A semicylindrical column was used to observe the phenomena in the grid zone from the transparent flat wall by video camera. An optical fiber probe measurement was also conducted simultaneously. The signals obtained by the sensor were compared with pictures from the video recorder and correlations between the phenomena and the signals were elucidated. Periodic effusion of particles from the annulus into the jet were apparently caused by jet constriction with the same frequency. The optical fiber probe measurement method was applied to a three-dimensional cylindrical bed. The effects of gas velocity, nozzle diameter, shape of the gas distributor on jet shape, jet constriction frequency and bubble frequency were discussed. It was suggested that the momentum of gas introduced from the nozzle should be able to be used to estimate the jet diameter and the jet height. It was also found that the jet shape was drastically affected by the shape of gas distributor. The jet constriction frequency was found to increase with gas flow rate from the nozzle.
