Abstract：Particle velocity in a 95 mm ID and a 200 mm ID fluidized bed was measured with PV6D reflective optical fiber probe. Based on the velocity measurement results, the turbulent fluidized bed was divided into 6 regions. The generation mechanisms of decelerating regions of top section and transition section in turbulent fluidized bed were analysed. Effects of fluidization section height, static bed height and gas velocity on decelerating regions were investigated. The results showed that the decelerating region on the top is caused by discharge section, while the decelerating region on the bottom is caused by the rapid change of solid concentration. The decelerating region on the top declined with the decreased fluidization section height, and shortened the length of fully developed section and accelerating section or even made them disappear. While the decelerating region on the bottom rose with the static bed height and descended with the gas velocity. The variation trend of decelerating regions was in accord with the one of transition section.
