Bubble
size and frequency in corrugated-wall bubbling fluidized beds – Image analysis
and neural network correlations
A. N. Khan Wardag, F. Larachi*, B.P.A. Grandjean
Department of Chemical
Engineering,
T
418-656-3566; F 418-656-5993; Email Faical.Larachi@gch.ulaval.ca
Abstract Digital image analysis was
implemented to monitor bubbling dynamics in corrugated-wall bubbling fluidized
beds (CWBFB) loaded with Geldart D particles. Various
geometrical configurations were investigated in terms of corrugation angle,
inter-wall clearance, and rest bed height and gas superficial velocity.
Implementation of wall corrugation led to improved gas-solid fluidization
quality with respect to flat-wall bubbling fluidized beds (FWBFB) as measured
in terms of retreat of the onset of bubbling as a function of gas
flow rate, of reduction of bubble sizes and rise velocities, and of
increase of bubble frequency. Two artificial neural network correlations valid
both for FWBFB and CWBFB were recommended for estimation of bubble frequency and
size using a common set of independent variables, i.e., gas superficial-minimum
bubbling velocity ratio, bed rest height, corrugation angle, average clearance,
and vertical location. The bubble frequency explicit
correlation accounted additionally for inter-wall minimum clearance and
distance between side wall and either neck or hip of front plate, at a given
elevation, whereas bubble size correlation needed bubble frequency as a
supplementary input variable.
Submitted to
You can get the simanndb-fb.zip file that contains an Excel
worksheet simulator to compute bubble diameter and frequency.
Other
links:
- Heat and Mass
Transfer in Co-Current Gas-Liquid Packed Beds Analysis, recommendations and
new correlations
- Predictions of
mass transfer for randomly packed towers operation
- Excel worksheets simulators for Trickle-bed
or Flooded Bed reactors or for predictions of mass transfer in randomly packed
towers operations
The neural
correlation was developped with the software NNFit