Influence of collisional parameters for rough particles on simulation of a gas-fluidized bed using a two-fluid model

Zhao, Yunhua; Lu, Bing; Zhong, Yingjie

doi:10.1016/j.ijmultiphaseflow.2014.12.002

Cited by 17 publications

(7 citation statements)

References 68 publications

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“…Closer to the gas-solid interface, the particle volume fraction decreases more sharply. This shows that the splash zone formed by the collapse of bubbles is a small area, which is consistent with previous studies [29,30]. The result from Figure 16 shows that the restitution coefficient had little effect on the axial profile of the jetsam volume fraction.…”

Section: Distribution Of Particle Volume Fractionsupporting

confidence: 91%

An Investigation of the Restitution Coefficient Impact on Simulating Sand-Char Mixing in a Bubbling Fluidized Bed

Zhao¹,

Eri²,

Wang³

2017

Energies

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Abstract:In the present work, the effect of the restitution coefficient on the numerical results for a binary mixture system of sand particles and char particles in a bubbling fluidized bed with a huge difference between the particles in terms of density and volume fraction has been studied based on two-fluid model along with the kinetic theory of granular flow. Results show that the effect of restitution coefficient on the flow characteristics varies in different regions of the bed, which is more evident for the top region of the bed. The restitution coefficient can be categorized into two classes. The restitution coefficients of 0.7 and 0.8 can be included into one class, whereas the restitution coefficient of 0.9 and 0.95 can be included into another class. Moreover, four vortices can be found in the time-averaged flow pattern distribution, which is very different from the result obtained for the binary system with the similar values between particles in density and volume fraction.

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Section: Distribution Of Particle Volume Fractionsupporting

confidence: 91%

An Investigation of the Restitution Coefficient Impact on Simulating Sand-Char Mixing in a Bubbling Fluidized Bed

Zhao¹,

Eri²,

Wang³

2017

Energies

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“…As further proof, the effective specularity coefficient is calculated to be ϕ ≈ 0.046 for β w = 0 and ϕ ≈ 0.053 for β w = 1. However, the influence of β w on this Couette flow seems to be slight, yet previous studies , have also shown that the collisional parameters, except for the tangential restitution coefficient, could have a profound influence on the gas-particle fluidization behavior.…”

Section: Numerical Tests and Resultsmentioning

confidence: 83%

“…Thus, unlike β w , μ w is much more sensitive in the present model. The sensitivity of μ w has also been demonstrated in the modeling of a bubbling fluidized bed …”

Section: Numerical Tests and Resultsmentioning

confidence: 98%

A Specularity Coefficient Model and Its Application to Dense Particulate Flow Simulations

Zhao

Ding

Zhu

et al. 2016

Ind. Eng. Chem. Res.

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The specularity coefficient is a key parameter for the Johnson and Jackson boundary conditions used in a two-fluid model (TFM), but it is experimentally unmeasurable. This work proposes a semianalytical and flow-dependent model for the specularity coefficient based on measurable particle properties and the data of Louge [Louge. Phys. Fluids, 1994, 6, 2253–2269]. Through TFM simulations, the model was tested in a granular Couette flow, a spouted bed, and a circulating fluidized bed riser. A discrete particle model (DPM) simulation of the Couette flow was also performed for comparison. It was found that the TFM results of the present model agreed with the DPM results and experimental data and thus justified the potential further applications of the model. Moreover, the parameter studies indicated that the friction coefficient between particle and wall was crucial to the present model.

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“…In bubbling fluidized beds, where the collision frequency between the particles is high, the effects of solid closures have been studied for example by Passalacqua et al (2009) and Farzaneh et al (2015) who examined the effect of frictional stress models. Zhao et al (2015) investigated the influence of collisional parameters, and Patil et al (2005a) studied the effects of the solid phase viscosity models. On circulating fluidized beds, the drag force between the gas and solid phases is widely considered to dominate the fluidization process.…”

Section: Introductionmentioning

confidence: 99%

Comparison of solid phase closure models in Eulerian-Eulerian simulations of a circulating fluidized bed riser

Nikku

Daikeler

Stroh

et al. 2019

Chemical Engineering Science

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In this work, computational fluid dynamics with Eulerian-Eulerian modeling approach is used in the investigation of the effect of the solid phase closure models on the hydrodynamics of a circulating fluidized bed riser. The studied models are the kinetic theory of granular flow and the powder modulus model. Computational performance and model prediction accuracy are investigated by performing transient simulations for three different cases and for different mesh sizes. The modeling results are compared with measured vertical pressure profile, external circulation mass flow rates, and particle velocity and concentration profiles obtained from a laboratory scale circulating fluidized bed unit. Additionally the computational times are compared to estimate the computational performance and to investigate if a simpler set of closures is computationally more affordable. The results indicate that both closure models can give good predictions for some quantities, while lacking in other quantities. The results indicate that the closure models for the solid phase have a noticeable effect on the model predictions, such as the vertical pressure profile and external circulation rate of the particles.

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Influence of collisional parameters for rough particles on simulation of a gas-fluidized bed using a two-fluid model

Cited by 17 publications

References 68 publications

An Investigation of the Restitution Coefficient Impact on Simulating Sand-Char Mixing in a Bubbling Fluidized Bed

An Investigation of the Restitution Coefficient Impact on Simulating Sand-Char Mixing in a Bubbling Fluidized Bed

A Specularity Coefficient Model and Its Application to Dense Particulate Flow Simulations

Comparison of solid phase closure models in Eulerian-Eulerian simulations of a circulating fluidized bed riser

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