T. Zarabi et A. Kantzas, Analysis of gamma-ray imaging data to describe hydrodynamic properties of gas-polyethylene fluidized beds, CAN J CH EN, 78(5), 2000, pp. 849-857
A scintillation gamma camera was used for measuring the instantaneous veloc
ity profile and average velocity as well as the trajectories of a radioacti
ve particle in small laboratory scale air-polyethylene-fluidized beds. A la
rge number of frames, with frequencies between 1 and 50 Hz, were analyzed t
o investigate the effects of bed height, gas velocity and particle morpholo
gy. Subsequently: (1) horizontal and axial variations of the particle veloc
ity were found; (2) three different flow zones along the axis (i.e., entran
ce zone, circulation zone and free board) were quantified; and (3) a charac
teristic time and a new definition of circulation (cycle) period were intro
duced. It was also found that the particle sometimes oscillates in the free
board or gets trapped in the entrance zone.