Local Interactive Patterns of Dispersed and Swarm Particles in a Circulating Fluidized-Bed Riser

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• 作者：Hiroyuki Hatano ; Satoru Matsuda ; Hiromi Takeuchi ; Alexander T. Pyatenko ; and Katsumi Tsuchiya
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：1996
• 出版时间：November 1996
• 年：1996
• 卷：35
• 期：11
• 页码：4360 - 4365
• 全文大小：166K
• 年卷期：v.35,no.11(November 1996)
• ISSN：1520-5045

文摘

Motion of glass beads of 0.4 mm mean diameter is observed in thecentral region of a circulatingfluidized-bed (CFB) riser by coupling a reflective-type particle imagescope (RPIS) with a high-speed video system of 3000 frames s^-1 recording rate.Transient changes in the particle velocityare measured under both dilute and dense conditions. The observedspeed of ascending particlesranges from 0 to 3.0 m s^-1 at a superficial gas velocityof 6.0 m s^-1. Descending particles arealso observed, and their speed ranges from 0 to 1.6 ms^-1. The structure and motion ofparticleswarms are analyzed with a special emphasis on particle collision.It is confirmed that thespeed, moving direction, and packed density of the particle swarms aresubjected to persistenttime variations. Various patterns of particle motions areidentified in the CFB riser, inducedby a diversity of collision mechanisms. These include momentumtransfer from a collidingparticle to other particles being contacted, grazing followed byparticle rotation, roundaboutmotion of a particle around another, simultaneous collision involvingmore than three particles,and successive particle collisions.