Adjustment of drag coefficient correlations in three dimensional CFD simulation of gas–solid bubbling fluidized bed

Esmaili, Ehsan; Mahinpey, Nader

doi:10.1016/j.advengsoft.2011.03.005

Cited by 85 publications

(59 citation statements)

References 58 publications

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“…The Gidaspow drag model combines the pressure drops from the Ergun equation and the Wen and Yu model [14] to derive the drag coefficient in the dense and dilute pockets of the bed, respectively, while the Syamlal-O'Brien model [42] converts the terminal velocity correlations to drag correlations adjusted to match the experimentally measured minimum fluidization velocity. Thus, the Gidaspow model is more applicable to homogeneous bubbling fluidization [54,55] while the adjusted Syamlal-O'Brien model is more suited at higher velocities [46]. This is in agreement with the comparison of bubble diameters predicted using the two drag models in Figure 17 for the experimental setup by Rüdisüli et al [20].…”

Section: Comparison Of Gas-solids Drag Modelssupporting

confidence: 80%

“…Although differences in the predictions have been noted previously (e.g. [43][44][45][46]), there has been no study extensively investigating the suitability of these models with varying bed geometries, particle properties and fluidization regimes. Through simulations conducted as part of this study, it is suggested that the Gidaspow model is more applicable to homogeneous bubbling fluidization (U/U mf <4) while the Syamlal-O'Brien model is more suited to faster fluidization and slugging (U/U mf >4).…”

Section: Governing Equationsmentioning

confidence: 87%

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Eulerian–Eulerian simulation of dense solid–gas cylindrical fluidized beds: Impact of wall boundary condition and drag model on fluidization

et al. 2015

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Modeling the hydrodynamics of dense-solid gas flows is strongly affected by the wall boundary condition and in particular, the specularity coefficient φ which characterizes the tangential momentum transfer from the particles to the wall. The focus of this study is to investigate the impact of φ on the fluidization hydrodynamics using a fully Eulerian description of the solid and gas phases in 3D cylindrical coordinates. In order to quantify this impact, tools for characterizing the bubbling dynamics and solids circulation are developed and applied to both lab-scale (diameters 10 cm and 14.5 cm) and pilot-scale (diameter 30 cm) cylindrical beds. Comparison of simulation predictions with experimental data for different fluidization regimes and particle properties suggests that values of φ in the range [0.01,0.3] are suitable for simulating most dense solid-gas flows of practical interest. It is also shown that for this range of φ, the fluidization hydrodynamics are not significantly dependent on the choice of φ especially as the bed diameter is increased. Additionally, 3D validation of the variable φ model by Li and Benyahia [1] shows the bubble diameter predictions to be in excellent agreement with experiment and the average value of φ predicted within the range [0.01,0.3]. Quantifying the impact of φ and establishing an appropriate range is not only important for accurate simulations at both lab and pilot scales but also validation of models and sub-models for a better understanding of the fluidization phenomenon. Finally, a comparison of the Gidaspow and Syamlal-O'Brien gas-solids drag model shows that the former is more applicable to homogeneous bubbling fluidization (U/U mf <4) while the latter is only suitable for high velocities (U/U mf >4) associated with larger bubbles and slugs.

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Section: Comparison Of Gas-solids Drag Modelssupporting

confidence: 80%

Section: Governing Equationsmentioning

confidence: 87%

Eulerian–Eulerian simulation of dense solid–gas cylindrical fluidized beds: Impact of wall boundary condition and drag model on fluidization

et al. 2015

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“…The reaction rate in each cell (molar rate of change from species A to species B per unit volume) was then implemented as a source term into Equation 13. Since the species had identical properties and the reaction occurred in a 1:1 stoichiometric ratio, no mass or momentum source terms were required.…”

Section: A S B S + → +mentioning

confidence: 99%

“…Other closure models also have an influence on the solution, but the most important of these, the drag law and the particle-particle restitution coefficient in particular, have been explored in quite some detail in the literature to date (e.g. [10][11][12][13][14]). This work will therefore include only a brief assessment of these and other potentially important factors.…”

Section: Introductionmentioning

confidence: 99%

The effect of frictional pressure, geometry and wall friction on the modelling of a pseudo-2D bubbling fluidised bed reactor

et al. 2015

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“…Esmaili and Mahinpey [12] have compared the results from the simulations with eleven different drag models with respect to minimum fluidization velocity, and found that Syamlal and O'Brien gives better prediction when compared with other models. In addition, the Syamlal and O'Brien drag is able to more accurately predict the minimum fluidization velocity.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation and experimental validation of the hydrodynamics in a 350 kW bubbling fluidized bed combustor

Belhadj

Chilton

Nimmo

et al. 2016

Int J Energy Environ Eng

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This paper presents experimentally validated three-dimensional numerical simulation of a 350 kW pilotscale bubbling fluidized bed combustor, which has been developed by using commercial CFD software package, Fluent 14.5. The solid particle distribution has been simulated by using the multiphase Euler-Euler Approach. The gas-solid momentum exchange coefficients were calculated by using Syamlal and O'Brien drag functions. The CFD model is created as the realistic representation of the actual pilot-scale bubbling fluidized bed. All simulations are performed in transient mode for an operation time of about 350 s. The experimental study is performed with silica sand particles with mean particle size of 0.6 mm and density of 1639 kg/m 3 . The bed was filled with particles up to a height of 0.30 m. The same conditions are used for the simulations. The present work combines both experimental and computational studies, where the CFD-Simulation results are compared to those obtained by experiments. The predicted simulation results of minimum fluidization velocity and pressure drop values of the pilot-scale bubbling fluidized bed combustor have good agreement with the experimental measurements.

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Adjustment of drag coefficient correlations in three dimensional CFD simulation of gas–solid bubbling fluidized bed

Cited by 85 publications

References 58 publications

Eulerian–Eulerian simulation of dense solid–gas cylindrical fluidized beds: Impact of wall boundary condition and drag model on fluidization

Eulerian–Eulerian simulation of dense solid–gas cylindrical fluidized beds: Impact of wall boundary condition and drag model on fluidization

The effect of frictional pressure, geometry and wall friction on the modelling of a pseudo-2D bubbling fluidised bed reactor

Numerical simulation and experimental validation of the hydrodynamics in a 350 kW bubbling fluidized bed combustor

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