Environmental Engineering Reference
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unsteady pathway that forms around 480 ms by the high-velocity jet in the absence
of the initial packed bed, which allows the energy in the jet to bypass the
fluidized
bed and prevents the critical pressure buildup as discussed in Sect. 4.2 . Since the
gas bubble formation and the solid particle recirculation are both driven by the
pressures at various locations in the system, the static pressure readings at pressure
taps P1
fl
- P5 are presented in Fig. 19 to assess the qualitative behavior observed from
the particle tracks in Fig. 18 .
The subplot at 400 ms in Fig. 19 shows a large pressure buildup of around
1,900 Pa at P1(
(fluidized bed). At 800 ms, when the bubble has collapsed, the initial
pressure buildup is lost and the pressure at P1 drops to around 1,250 Pa. Subse-
quently, at 1,200 and 1,600 ms, the pressure at P1 increases slightly to around 1,400
and 1,350 Pa, respectively. This renewed increase in pressure is in line with the
observation of the second and third gas bubbles formations; the slight increase also
explains why the subsequent bubbles did not carry suf
fl
cient kinetic energy to reach
the top of the reactor. Figure 19 also shows a consistent positive pressure differ-
ential between the loop seal and the
- P1), which corroborates the
continuous recirculation of particles from the loop seal to the fuel reactor observed
from the particle tracks.
In the absence of experimental results of CD-CLC operation with Group D-type
particles from Geldart
fl
fluidized bed (P4
'
cation ( 1973 ), the successful incorporation
of chemical reactions into the multiphase flow simulation is judged by inspecting
the formation of Fe 3 O 4 and CO 2 as a result of the reaction described in Eq. ( 3 ).
These results are presented in Figs. 20 and 21 , respectively.
s powder classi
Fig. 19 Static pressure at pressure taps P1
- P5att = 400 ms (upper left), 800 ms (upper right),
1,200 ms (lower left), and 1,600 ms (lower right) in reacting
fl
ow
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