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1 | CIRCULATING FLUIDIZED BED
Circulating Fluidized Bed
Introduction
This model simulates the operation of a circulating fluidized bed. In this apparatus the
dispersed phase, consisting of solid spherical particles, is fluidized by a gas and
transported through a vertical riser. Upon reaching the outlet, the dispersed phase is
re-injected in the vicinity of the gas inlet at the bottom of the bed. To study the flow
in the fluidized bed, the model uses the Euler-Euler model. The phase properties and
model setup follow those in Ref. 1.
Model Definition
Figure 1 displays the geometry of the fluidized bed, and schematically describes its
means of operation. The fluid phase, consisting of air, is injected at the bottom of the
b
ed. The dispersed phase, particles with a diameter of 54 μm, are fluidized by the gas
flow and transported upwards. At the outlet, particles and gas exit the bed. The
particles are fed back into the bed through re-injection inlets on the vertical walls near
the gas inlet. The dispersed phase flux matches that at the outlet, creating a circulating
fluidized bed. Table 1 summarizes the bed geometries and the properties of the phases.
The values correspond to those used in Ref. 1.
PROPERTY VALUE
Particle diameter 54 μm
Particle density 930 kg/m
3
Gas density (air) 1.2 kg/m
3
Gas dynamic viscosity (air) 1.8·10
-5
kg/m
3
Gas inlet velocity 1.52 m/s
Bed width 0.09 m
Bed height 10.6 m
TABLE 1: FLUIDIZED BED PROPERTIES
- 1
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