Numerical simulation of the gas-solid flow in a fluidized bed by combining discrete particle method with computational fluid dynamics

Xu, Bao‐Hua; Yu, Aibing

doi:10.1016/s0009-2509(97)00081-x

Cited by 829 publications

(384 citation statements)

References 29 publications

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“…The most detailed description is the Discrete Particle Model (DPM) or the Lagrangian-Eulerian framework where the solid phase consists of individual particles interacting with each other and the continuous gas phase [3][4][5]. Current computational resources, however, limit the number of solid particles that can be tracked simultaneously making the approach only feasible for dilute solid-phase flows [6].…”

Section: Introductionmentioning

confidence: 99%

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: Introductionmentioning

confidence: 99%

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 method for CFD-DEM simulations has been well established [20][21][22]. The method used in this work is the same as before, not described here for brevity.…”

Section: Model Descriptionmentioning

confidence: 99%

DEM simulation of particle descending velocity distribution in the reduction shaft furnace

Bai

2016

Metall. Res. Technol.

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-Reduction shaft furnace is a promising alternative to blast furnace ironmaking. The particle descending velocity distribution has a great influence on the shaft furnace, which directly affects the production index and further the shaft furnace normal smelting. Therefore, a three-dimensional model (3D) is established based on the discrete element method (DEM) and computation fluid dynamic (CFD). The effect of the gas flow in the shaft furnace, the height, the diameter and the bosh angle of the shaft furnace on the particle descending velocity distribution during discharging process is investigated by the model and analyzed based on the granular dynamic theory and Janssen theory. The results show that the particle velocity reduces along the radius. The effect of the gas flow on the velocity distribution is insignificant. In order to obtain a uniform velocity distribution, it is better to increase the height, or the diameter, or to decrease the bosh angle. An improved model is proposed for the uniform velocity distribution at last.B ecause of its fast reduction rates, consistent product quality, minimal environmental impacts, and great flexibility, reduction shaft furnace is a promising alternative to blast furnace ironmaking [1]. In the shaft furnace production, iron ore particles are charging in the shaft furnace, and the reducing gas having high temperature is blown from tuyeres, then the particles are reduced during descending. If the particle descending velocity distribution is not reasonable, the iron ore particles will not be reduced better, causing the production index decreases and further affecting the shaft furnace normal smelting. Consequently, it is necessary to focus on researching the particle descending velocity distribution in the shaft furnace.Hence many researches had been investigated about the solid flow [2-6], these results are helpful for an overall understanding of the solid flow. To sum up, there have been two approaches adopted for the solid flow research, such as the physical simulation [2][3][4] and the mathematical simulation [5,6]. Compared with the mathematical simulation, the physical simulation is hard to analyze the solid flow quantificationally. Kou et al. [5] researched the effect of the bottom diameter of COREX shaft furnace, the cylinder height and the screw flight diameter on the particle velocity distribution based on DEM. However, the model he developed is not taken into account the effect of the gas flow in the shaft furnace, the height, the diameter and the bosh angle of the shaft furnace on the particle descending velocity.Numerical simulation analysis for solid flow in shaft furnace is a useful tool to understand the behavior of solid flow. So far, DEM has become one of the most powerful simulation methods for granular behaviors. In the ironmaking field, many researches [5][6][7][8] had been studied about the granular behavior based on DEM, and the simulation results coincided well with the experiments and industrial operation. It can be found that DEM is well ...

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“…E p f a (7) friction wall normal f f (8) The f D is a function of particle mass, relative velocity between fluid and particle velocity and a time scale. This time scale is the response time of the …”

Section: Numerical Model 21 Discrete Particle Phasementioning

confidence: 99%

“…Considering the convenient way to rescale parameters and extract the data, numerical simulation is proposed and exploited to provide an insight into the particle movement under accelerated air ventilation circumstances. Commonly, mathematical model of numerical simulation can be divided into two categories: the continuum-continuum approach represented by two-fluid model [5], and the continuum-discrete approach represented by CFD-DPM (the combination of Computational Fluid Dynamics and Discrete particle Model) [6][7][8][9]. In the present work, particle phase is regarded as a discrete phase at a microscopic level so that the interaction forces between particle-fluid is taken into account.…”

Section: Introductionmentioning

confidence: 99%

Euler-Lagrange Simulation of Fine Particle Discharge Rate under Accelerated Air Ventilation Circumstances

Wang

Zhao

et al. 2014

JAPANESE JOURNAL OF MULTIPHASE FLOW

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Numerical simulation of the gas-solid flow in a fluidized bed by combining discrete particle method with computational fluid dynamics

Cited by 829 publications

References 29 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

DEM simulation of particle descending velocity distribution in the reduction shaft furnace

Euler-Lagrange Simulation of Fine Particle Discharge Rate under Accelerated Air Ventilation Circumstances

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