References(24) Cited-By(9) Particle motion in the grid zone above a perforated plate distributor was investigated with 15-cmφ circular and 10-cmφ semicircular fluidized beds. Tracer method was applied to observe dead zone shape and particle movement visually. The particle motion in the grid zone was found to be rather stable, similarly to that in a spouted bed. Particle entrainment rate in a jet was determined from the observed values of particle stream function in the annular region. This particle circulation, which is the essential scheme of gas-solid contact in grid zone, is mainly controlled by the gas velocity through an orifice. Dead zone is formed under a mechanism similar to that of bulk solids flow in a bin. Correlations are presented for estimating the size of true and pseudo-dead zones and the particle turnover rate in the pseudo-dead zone.
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