Lagrangian and Eulerian drag models that are consistent between Euler-Lagrange and Euler-Euler (two-fluid) approaches for homogeneous systems

S. Balachandar

doi:10.1103/physrevfluids.5.084302

Investigation of drag models for the two fluid simulation of Geldart group A powders

Powder Technology ◽

10.1016/j.powtec.2016.07.063 ◽

2016 ◽

Vol 304 ◽

pp. 41-54 ◽

Cited By ~ 5

Author(s):

X. Lu ◽

D.J. Holland

Keyword(s):

Fluid Simulation ◽

Group A ◽

Drag Models ◽

Two Fluid

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Two-fluid Modeling of Geldart A Particles in Gas-solid Bubbling Fluidized Bed: Assessment of Drag Models and Solid Viscosity Correlations

International Journal of Chemical Reactor Engineering ◽

10.1515/ijcre-2017-0016 ◽

2017 ◽

Vol 16 (3) ◽

Cited By ~ 1

Author(s):

Tian Tian ◽

Zhengrui Jia ◽

Shujun Geng ◽

Xiaoxing Liu

Keyword(s):

Fluidized Bed ◽

Viscosity Model ◽

Frictional Stress ◽

Concentration Profiles ◽

Solid Concentration ◽

Drag Model ◽

Bubbling Fluidized Bed ◽

Drag Models ◽

Bed Expansion ◽

Two Fluid

AbstractIn this work the influences of solid viscosity and the way to scale-down traditional drag models on the predicted hydrodynamics of Geldart A particles in a lab-scale gas-solid bubbling fluidized bed are investigated. To evaluate the effects of drag models, the modified Gibilaro et al. drag model (constant correction factor) and the EMMS drag model (non-constant correction factor) are tested. And the influences of solid viscosity are assessed by considering the empirical model proposed by Gidaspow et al. (1997, Turbulence, Viscosity and Numerical Simulation of FCC Particles in CFB. Fluidization and Fluid-particle Systems, AIChE Annual Meeting, Los Angeles, 58–62) and the models based on kinetic theory of granular flow (KTGF) with or without frictional stress. The resulting hydrodynamics by incorporating the different combinations of the drag model and solid viscosity model into two-fluid model (TFM) simulations are compared with the experimental data of Zhu et al. (2008, Detailed Measurements of Flow Structure inside a Dense Gas-Solids Fluidized Bed.”Powder Technological180:339–349). The simulation results show that the predicted hydrodynamics closely depends on the setting of solid viscosity. When solid viscosity is calculated from the empirical model of Gidaspow et al., both drag models can reasonably predict the radial solid concentration profiles and particle velocity profiles. When the KTGF viscosity model without frictional stress is adopted, the EMMS drag model significantly over-estimates the bed expansion, whereas the modified Gibilaro et al. drag model can still give acceptable radial solid concentration profiles but over-estimate particle upwards and downwards velocity. When KTGF viscosity model with frictional stress is chosen, both drag models predict the occurrence of slugging. At this time, the particle velocity profiles predicted by EMMS drag model are still in well agreement with the experimental data, but the bed expansion is under-estimated.

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Performance improvement of existing drag models in two-fluid modeling of gas–solid flows using a PR-DNS based drag model

Powder Technology ◽

10.1016/j.powtec.2015.07.001 ◽

2015 ◽

Vol 286 ◽

pp. 257-268 ◽

Cited By ~ 4

Author(s):

Ahmadreza Abbasi Baharanchi ◽

Seckin Gokaltun ◽

George Dulikravich

Keyword(s):

Performance Improvement ◽

Fluid Modeling ◽

Drag Model ◽

Drag Models ◽

Two Fluid

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The Effect of Closure Laws on the Simulation Results of Two-Fluid Model of Gas-Solid Flows

Volume 7A: Fluids Engineering Systems and Technologies ◽

10.1115/imece2015-51760 ◽

2015 ◽

Author(s):

Yifei Duan ◽

Zhi-Gang Feng

Keyword(s):

Heat Transfer ◽

Large Scale ◽

Fluid Model ◽

Transfer Model ◽

Hill Model ◽

Simulation Results ◽

Two Fluid Model ◽

Drag Models ◽

Closure Laws ◽

Two Fluid

There are two primary approaches in modeling fluid-solid flows based on the method of treating particles suspended in flows. The first approach is the Eulerian-Lagrangian or Discrete Element Method (DEM) approach that tracks individual particles by solving the equations of motion of these particles. The second approach is the Eulerian-Eulerian approach or two-fluid model (TFM) that considers particles as another continuum phase or fluid. The TFM is preferred in modeling and predicting gas-solid flow behaviors in many engineering applications because of its efficiency in handling large-scale complex systems with large number of particles. However, one of the challenges in TFM is the uncertainty related to the selection of closure laws and transport properties of solid phases. In this study we employ the MFIX code, a general-purpose TFM computer code developed at the National Energy Technology Laboratory, to investigate the effect of different drag models and heat transfer models on the simulation results on the flow hydrodynamics and heat transfer of gas-solid fluidized beds. Three drag models (Gidspow model, Syamlal-O’Brien model, and Koch-Hill model) and two heat transfer model (Gunn model and a recently developed model by Sun et al., 2015) are tested. Simulation results from these models are compared with experimental measurements. The accuracy and applicability of these models are assessed and discussed.

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