M. Al-dahhan

ABSTRACT The effect of gas sparger design on the gas holdup radial profile in a bubble column (with a diameter of 0.162 m) has been studied using γ-ray computed tomography (CT). Six different configurations of gas spargers were examined, using an air−water system for selected superficial gas velocities from 2 cm/s to 30 cm/s, covering the homogeneous and heterogeneous (churn-turbulent) flow regimes. Two operating pressures were used: 1 and 4 atm. Differences were found between the gas holdup distributions produced by different spargers at dimensionless radii of r/R < 0.8 in the central region of the column. The cross and single nozzle spargers produced closely similar gas holdup distributions, while the perforated plate sparger produced a higher gas holdup when compared to other spargers with the same percentage open area (POA). At 4 atm, the sparger design did not have a significant effect on the gas holdup profiles, compared to atmospheric pressure, except for the case of the single-hole sparger, which was found to yield a higher gas holdup.

The Kolmogorov entropy (KE) algorithm was successfully applied to single source γ-ray Computed Tomography (CT) data measured by three scintillation detectors in a 0.162 m-ID bubble column equipped with a perforated plate distributor (163 holes × ∅ 1.32Á10–3 m). The aerated ...

A double-slit model developed can predict the frictional two-phase pressure drop, external liquid holdup, pellet-scale external wetting efficiency, and gas-liquid interfacial area in cocurrent downflow trickle-bed reactors operated under partially wetted conditions in the trickle flow regime. The model, an extension of the Holub et al. (1992, 1993) mechanistic pore-scale phenomenological approach, was designed to mimic the actual bed void

In recent years, computational fluid dynamics CFD has become an important tool in studies of multiphase flows. It is expected that CFD modeling will become more pervasive in the design of multiphase reactors as researchers in both aca-demic and industrial communities are ...

The Eulerian k-fluid CFD model was used to simulate the macroscale multiphase flow in packed beds. The geometric complexity of the bed structure is resol®ed by statis-tically describing the porosity distribution. The complicated multiphase interactions are computed using the ...