CFD studies of solids hold-up distribution and circulation patterns in gas–solid fluidized beds

Hosseini, Seyyed Hossein; Ahmadi, Goodarz; Rahimi, Rahbar; Zivdar, Mortaza; Esfahany, Mohsen Nasr

doi:10.1016/j.powtec.2010.02.024

Cited by 58 publications

(21 citation statements)

References 48 publications

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“…This was equally done by Hosseini et al (2010), incorporating also in the comparison the velocity vectors from Laverman et al (2008). These results evidence a clear resemblance in the particle recirculation patterns obtained in simulation and experiments, but it appears that the simula tions over predict the modulus of the particle velocity vectors for small superficial velocities (U/U mf ¼1.65 in Lindborg et al, 2007), and that the prediction of the vertical position of the recirculation centre is not completely satisfactory (Hosseini et al, 2010). Ahuja and Patwardhan (2008), for U/U mf ¼5.6, as well as Wang and Liu (2010), this last study using FCC particles, compared their two dimensional simulation results with three dimensional experiments and found acceptable agreement in the radial pro files of velocity.…”

Section: Introductionmentioning

confidence: 98%

“…Lindborg et al (2007) made a qualitative comparison of the velocity vector fields of two dimensional simulations and three dimensional measurements taken from Lin et al (1985). This was equally done by Hosseini et al (2010), incorporating also in the comparison the velocity vectors from Laverman et al (2008). These results evidence a clear resemblance in the particle recirculation patterns obtained in simulation and experiments, but it appears that the simula tions over predict the modulus of the particle velocity vectors for small superficial velocities (U/U mf ¼1.65 in Lindborg et al, 2007), and that the prediction of the vertical position of the recirculation centre is not completely satisfactory (Hosseini et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

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Comparison between two-fluid model simulations and particle image analysis & velocimetry (PIV) results for a two-dimensional gas–solid fluidized bed

Hernández-Jiménez

Sánchez-Delgado

Gómez-García

et al. 2011

Chemical Engineering Science

108

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a b s t r a c tThis work compares simulation and experimental results of the hydrodynamics of a two dimensional, bubbling air fluidized bed. The simulation in this study has been conducted using an Eulerian Eulerian two fluid approach based on two different and well known closure models for the gas particle interaction: the drag models due to Gidaspow and Syamlal & O'Brien. The experimental results have been obtained by means of Digital Image Analysis (DIA) and Particle Image Velocimetry (PIV) techniques applied on a real bubbling fluidized bed of 0.005 m thickness to ensure its two dimensional behaviour. Several results have been obtained in this work from both simulation and experiments and mutually compared. Previous studies in literature devoted to the comparison between two fluid models and experiments are usually focused on bubble behaviour (i.e. bubble velocity and diameter) and dense phase distribution. However, the present work examines and compares not only the bubble hydrodynamics and dense phase probability within the bed, but also the time averaged vertical and horizontal component of the dense phase velocity, the air throughflow and the instantaneous interaction between bubbles and dense phase. Besides, quantitative comparison of the time averaged dense phase probability as well as the velocity profiles at various distances from the distributor has been undertaken in this study by means of the definition of a discrepancy factor, which accounts for the quadratic difference between simulation and experiments The resulting comparison shows and acceptable resemblance between simulation and experiments for dense phase probability, and good agreement for bubble diameter and velocity in two dimensional beds, which is in harmony with other previous studies. However, regarding the time averaged velocity of the dense phase, the present study clearly reveals that simulation and experiments only agree qualitatively in the two dimensional bed tested, the vertical component of the simulated dense phase velocity being nearly an order of magnitude larger than the one obtained from the PIV experiments. This discrepancy increases with the height above the distributor of the two dimensional bed, and it is even larger for the horizontal component of the time averaged dense phase velocity. In other words, the results presented in this work indicate that the fine agreement commonly encountered between simulated and real beds on bubble hydrodynamics is not a sufficient condition to ensure that the dense phase velocity obtained with two fluid models is similar to that from experimental measurements on two dimensional beds.

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Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Comparison between two-fluid model simulations and particle image analysis & velocimetry (PIV) results for a two-dimensional gas–solid fluidized bed

Hernández-Jiménez

Sánchez-Delgado

Gómez-García

et al. 2011

Chemical Engineering Science

108

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“…The real configuration of gas distributor is not considered in this work, and we assumed that the metal sintered plate can satisfy the uniform distribution of the entering gas quite well. Since the distributor configuration actually may have a drastic influence on solids motion particularly near the distributor [74,75], we believe that the solid volume fraction distribution in this region will be simulated better if the geometric form of the distributor is treated carefully. Syamlal and O'Brien drag model with the modified constants in Table 4 was also applied to predict hydrodynamic behavior of irregular particles in IPE experimental beds.…”

Section: Solid Volume Fractionmentioning

confidence: 99%

Eulerian–Eulerian simulation of irregular particles in dense gas–solid fluidized beds

Hua

Zhao

et al. 2015

Powder Technology

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“…Behjat, Shahhosseini, and HashemabadI (2008), in a study of hydrodynamics and heat transfer in a fluidized bed, found that Syamlal and O'Brien model presented better prediction of bed expansion and gas-solid hydrodynamics than Gidaspow model, while in the prediction of bubble shape, both models presented similar results. Hosseini et al (2010) state that the drag model is a key parameter in modeling gas-solid flows. They analyzed results predicted using Syamlal and O'Brien, Gidaspow and (2015) performed three dimensional simulations of a BFB employing the TFM approach and different drag models.…”

Section: Introductionmentioning

confidence: 99%

Numerical study of gas–solid drag models in a bubbling fluidized bed

Zinani

Philippsen

Indrusiak

2016

Particulate Science and Technology

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Bubbling fluidized beds find application mainly in power conversion industries. For design, dimensioning and operation of fluidized bed equipment, the understanding of multiphase gas-solid flows is of great importance. The use of Computational Fluid Dynamics in the simulation of gassolid systems is limited by the complexity of mathematical models, which rely on a series of empirical or theoretical correlations. In the present work, the code MFIX was employed to simulate flows in a bubbling fluidized bed and to compare results predicted using different gas-solid drag Downloaded by [University of Technology Sydney] at 06:08 22 June 2016 2 models. A Two Fluid Model with Kinetic Theory of Granular Flows (TFM-KTGF) was employed, in which gas-solid drag correlations, such as Gidaspow, Hill-Koch-Ladd or Syamlal and O'Brien were applied to model momentum transfer between phases. The results predicted were compared with each other and with experimental results from the literature. It was found that the results predicted using each model differ much. Gidaspow and Hill-Koch-Ladd models yielded bubbles with shapes more similar to the experiments.

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CFD studies of solids hold-up distribution and circulation patterns in gas–solid fluidized beds

Cited by 58 publications

References 48 publications

Comparison between two-fluid model simulations and particle image analysis & velocimetry (PIV) results for a two-dimensional gas–solid fluidized bed

Comparison between two-fluid model simulations and particle image analysis & velocimetry (PIV) results for a two-dimensional gas–solid fluidized bed

Eulerian–Eulerian simulation of irregular particles in dense gas–solid fluidized beds

Numerical study of gas–solid drag models in a bubbling fluidized bed

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