CFD simulation of gas–solid bubbling fluidized bed: A new method for adjusting drag law

Vejahati, Farshid; Mahinpey, Nader; Ellis, Naoko; Nikoo, Mehrdokht B.

doi:10.1002/cjce.20139

Cited by 106 publications

(64 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The literature on this topic is abundant; from the earlier works of Boemer et al (1998), and Van Wachem et al (1998), to the more recent studies comprising image analysis (Busciglio et al, 2009), particle drag optimisation procedures (Mahinpey et al, 2007;Vejahati et al, 2009), and time averaged volume fraction (Deza et al, 2009;Min et al, 2010;. Particularly, the works of Deza et al (2009) and Min et al (2010) show a reasonable agreement between two dimensional (2D) and three dimensional (3D) simulations and X ray imaging experiments of cylindrical fluidized beds of internal diameter of 0.095 and 0.152 m, respectively.…”

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

109

View full text Add to dashboard Cite

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.

show abstract

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

109

View full text Add to dashboard Cite

show abstract

“…The flow of this multiphase model is given by the continuity and momentum equations. The gas and solid phase momentum and continuity equations are given for each phase [8,20,23]. The gas and solid phase continuity equations can be written as follows:…”

Section: O the Euler-euler Approach Equationsmentioning

confidence: 99%

Numerical Model and Experimental Validation of the Hydrodynamics in an Industrial-Scale Sewage Sludge Bubbling Fluidized Bed Incinerator

Belhadj¹,

Nimmo²

2017

IJERA

View full text Add to dashboard Cite

This paper describes a development of a numerical model and experimental validation of the hydrodynamics in industrial-scale sewage sludge bubbling fluidized bed incinerator. The numerical model and simulations are performed using commercial CFD software package ANSYS Fluent 14.5. The complex geometry of the developed numerical model represents the actual industrial-scale bubbling fluidized bed combustor. The gassolid flow behaviour inside the bed was described using the Eulerian-Eulerian multiphase model. The momentum exchange coefficients between the gas phase and solid particles were described by the Syamlal and O'Brien drag model equations. The CFD transient simulations were run for 350 seconds at the optimum operating conditions of the used fluidized bed with bed temperature of 850°C. The experiments were carried out using quartz sand with three different particle sizes having a diameters ranging from 0.5 mm to 1.5 mm and a density of 2650 kg/m³. The industrial-scale furnace was filled with bed material to a bed height of 0.85 m. The same operating parameters have been applied for both experimental and numerical studies. The hydrodynamics of the gas-solid industrial-scale bubbling fluidized bed at operating conditions are investigated in the CFD numerical model and simulations of this three-dimensional (3D) complex geometry. To estimate the prediction quality of the simulations based on the developed numerical model, the minimum fluidization gas velocity and pressure drop results obtained from the CFD simulations are validated with the experimental measurements. The generated simulation results of the pressure drop and minimum fluidization gas velocity of the industrial-scale sewage sludge incinerator based the Eulerian-Eulerian method and Syamlal and O'Brien drag model are in good agreement with the experimental measured data.

show abstract

“…Bubbles coalesce and break-up as fluid flow is increased. Finally, the bubbles become large enough to occupy a substantial fraction of the cross-section of the small diameter columns (Vejahati 2006). These large bubbles are called slug, as shown in the third column of Figure 1.…”

Section: Flow Regimes In Fluidized Bedsmentioning

confidence: 99%

Fluid Dynamics of Gas - Solid Fluidized Beds

Silva¹,

Jiménez²,

Salazar³

2012

Advanced Fluid Dynamics

View full text Add to dashboard Cite

CFD simulation of gas–solid bubbling fluidized bed: A new method for adjusting drag law

Cited by 106 publications

References 41 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

Numerical Model and Experimental Validation of the Hydrodynamics in an Industrial-Scale Sewage Sludge Bubbling Fluidized Bed Incinerator

Fluid Dynamics of Gas - Solid Fluidized Beds

Contact Info

Product

Resources

About