On the role of fluids in stick-slip dynamics of saturated granular fault gouge using a coupled computational fluid dynamics-discrete element approach

A coupled computational fluid dynamics (CFD)/discrete element method (DEM) is used to simulate the gas–solid two-phase flow in a laboratory-scale spouted fluidized bed. Transient experimental results in the spouted fluidized bed are obtained in a special test rig using the high-speed imaging technique. The computational domain of the quasi-three-dimensional (3D) spouted fluidized bed is simulated using the commercial CFD flow solver ANSYS-fluent. Hydrodynamic flow field is computed by solving the incompressible continuity and Navier–Stokes equations, while the motion of the solid particles is modeled by the Newtonian equations of motion. Thus, an Eulerian–Lagrangian approach is used to couple the hydrodynamics with the particle dynamics. The bed height, bubble shape, and static pressure are compared between the simulation and the experiment. At the initial stage of fluidization, the simulation results are in a very good agreement with the experimental results; the bed height and the bubble shape are almost identical. However, the bubble diameter and the height of the bed are slightly smaller than in the experimental measurements near the stage of bubble breakup. The simulation results with their experimental validation demonstrate that the CFD/DEM coupled method can be successfully used to simulate the transient gas–solid flow behavior in a fluidized bed which is not possible to simulate accurately using the granular approach of purely Euler simulation. This work should help in gaining deeper insight into the spouted fluidized bed behavior to determine best practices for further modeling and design of the industrial scale fluidized beds.

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A Novel Approach For Analyzing Mixing Quality In Solid-Liquid Stirred Tanks Via Coupled Computational Fluid Dynamics - Discrete Element Method And Electrical Resistance Tomography

10.32920/ryerson.14655444.v1 ◽

2021 ◽

Author(s):

Cindy Tran

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Discrete Element Method ◽

Electrical Resistance ◽

Particle Interaction ◽

Discrete Element ◽

Fluid Particle ◽

Electrical Resistance Tomography ◽

Mixing Quality ◽

Solid Liquid

The mixing quality of a solid-liquid stirred tank operating in the turbulent regime was investigated, numerically and to an extent experimentally. Simulations were performed by coupling Computational Fluid Dynamics (CFD) and the Discrete Element Method (DEM). The results were evaluated against experimental data obtained using Electrical Resistance Tomography (ERT). This facilitated a novel and more rigorous assessment of CFD-DEM coupling – i.e. based on the spatial distribution of particle concentrations. Furthermore, a new mixing index definition was developed to quantify suspension quality to work in tandem with existing dispersion mixing indexes. This provides a more complete interpretation of mixing quality. In this work, it was found that the model underestimated suspension and dispersion due to model limitations associated with mesh size and fluid-particle interaction models. Furthermore, the predicted mixing quality was sensitive to changes in the drag model, including other fluid-particle interaction forces in simulations, and variations in certain particle properties

Download Full-text

A Novel Approach For Analyzing Mixing Quality In Solid-Liquid Stirred Tanks Via Coupled Computational Fluid Dynamics - Discrete Element Method And Electrical Resistance Tomography

10.32920/ryerson.14655444 ◽

2021 ◽

Author(s):

Cindy Tran

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Discrete Element Method ◽

Electrical Resistance ◽

Particle Interaction ◽

Discrete Element ◽

Fluid Particle ◽

Electrical Resistance Tomography ◽

Mixing Quality ◽

Solid Liquid

The mixing quality of a solid-liquid stirred tank operating in the turbulent regime was investigated, numerically and to an extent experimentally. Simulations were performed by coupling Computational Fluid Dynamics (CFD) and the Discrete Element Method (DEM). The results were evaluated against experimental data obtained using Electrical Resistance Tomography (ERT). This facilitated a novel and more rigorous assessment of CFD-DEM coupling – i.e. based on the spatial distribution of particle concentrations. Furthermore, a new mixing index definition was developed to quantify suspension quality to work in tandem with existing dispersion mixing indexes. This provides a more complete interpretation of mixing quality. In this work, it was found that the model underestimated suspension and dispersion due to model limitations associated with mesh size and fluid-particle interaction models. Furthermore, the predicted mixing quality was sensitive to changes in the drag model, including other fluid-particle interaction forces in simulations, and variations in certain particle properties

Download Full-text