Computational Fluid Dynamics Evaluation of the Influence of Cone Geometry on Solids Circulation in Spouted Beds

Souza, Amarílis Severino e; Freire, José Teixeira; Béttega, Rodrigo

doi:10.1021/acs.iecr.8b03505

Cited by 12 publications

(6 citation statements)

References 37 publications

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“…Spout deflection is a typical instability phenomenon in spouted and spout-fluidized beds. It can cut-off the normal particle movement circulation, which is the resort of high interaction efficiency of the gas–solid phases in spouted and spout-fluidized beds. − Thus, to eliminate the spout deflection and achieve stable spouting quality, various modifications to the reactor geometry have been tried, such as adjusting the gas inlet device shape, − adjusting the slot angle, ,, and installing draft plates. − However, these modifications have side effects on the hydrodynamics of gas–solid systems, such as lowering the solid circulation velocity or enhancing the spout incoherence . Moreover, the fundamentals related to spout deflection have not been well understood, especially under various operational conditions.…”

Section: Introductionmentioning

confidence: 99%

Particle-Scale Study of the Effect of Operating Conditions on Spout Deflection Behavior in a Flat-Bottomed Spout-Fluidized Bed

Yue

Shen

2019

Ind. Eng. Chem. Res.

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Spout deflection is a common instability phenomenon in spout-fluidized beds. The hydrodynamics of spout deflection under several key operating variables, including static bed height (H 0), background velocity (U bg), and reactor column width (W), is investigated by means of the computational fluid dynamic-discrete element method (CFD-DEM) coupling approach. The results show that non-alternating spout deflection can be easily observed when the H 0 is larger than 236 mm or the W is less than 0.14 m in this study. For alternating spout deflection, first, there is an upper limit for its amplitude because of the self-locking phenomenon in the bottom corner. Large W promotes the regularity, while the effects of H 0 on regularity is neglectable. Thirdly, the main frequency of the alternating spout deflection reduces with increasing H 0 and increasing U bg and finally stabilizes at 1.7 Hz. This study sheds light on the design, optimization, and operation of spout-fluidized beds.

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Section: Introductionmentioning

confidence: 99%

Particle-Scale Study of the Effect of Operating Conditions on Spout Deflection Behavior in a Flat-Bottomed Spout-Fluidized Bed

Yue

Shen

2019

Ind. Eng. Chem. Res.

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“…• Particle residence times are often considered to be fixed despite the fact that it is well-known that they are correlated with bed configuration and operating parameters.…”

Section: Introductionmentioning

confidence: 99%

Two-Fluid-Model-Based Full Physics Simulations of Mixing in Noncohesive Wet Fluidized Beds

Askarishahi

Salehi

Radl

2019

Ind. Eng. Chem. Res.

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Mixing in a noncohesive wet fluidized bed was studied using the two-fluid model (TFM) and a zero-dimensional (0D) approach. The employed TFM was extended to simulate droplet deposition on the particles, droplet evaporation, and particle drying. To quantify the bed uniformity, the variance of temperature and the particles’ loss on drying (LoD) field were computed. Subsequently, our TFM simulation data is used to support the assumptions adopted in our 0D model. Specifically, the simulation results suggest the formation of two well-mixed zones: a spraying/wetting zone and a drying zone. Furthermore, it was demonstrated that the 0D model can accurately predict the gas and particle temperatures, as well as the moisture content with a maximum error of 4.3% when the following criteria are met: (i) low enough temperature and LoD variance (i.e., less than 5%); (ii) deep droplet penetration into the bed; (iii) no droplet loss.

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“…The first, known as TFM (Two fluid model), considers the solid and fluid phases as continuous and interpenetrating, and the properties of the solid phase can be described by the Kinetic Theory of Granular Flow (KTGF). This approach is widely used [1][2][3][4]. The second, called CFD-DEM coupled (Computational Fluid Dynamics/Discrete Element Method), considers the fluid phase as continuous, while the solid phase is treated as discrete from the modeling of the individual motion of each particle present in the system.…”

Section: Introductionmentioning

confidence: 99%

“…The literature reports several models to obtain the drag coefficient. In TFM simulations, Gidaspow drag model [20] is widely used in spouted bed simulations [3,4,[21][22][23]. However, there is no such agreement for CFD-DEM simulations.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of different mathematical models in the CFD-DEM simulation of conical spouted bed fluid dynamics

Béttega

2021

CI&CEQ

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The input parameters, empirical, and semi-empirical models significantly influence the responses obtained by CFD-DEM simulations. In this work, the effect of three turbulence models, three conditions of the particle rotation, and five drag models on the fluid dynamic behavior of a conical spout bed applied to the drying of sorghum grains were evaluated. Experimental data on the solids pressure drop, height, and shape of the fountain were used to validate the simulations. Results showed the importance of including the particle rotation in the model to approximate the results simulated with the experimental behavior. Compared with experimental data, considering the particle rotation by Dennis et al. model, the deviation was of the 2% for the fountain height and 9.18% for the pressure drop. While for the model without the particle rotation, the deviations were 106.33% and 42.31% for the fountain height and pressure drop, respectively. For the analyzed case, the standard k-? turbulence model showed a greater agreement with the experimental data. For the drag models evaluated, the best fit with the experimental data was obtained by the Koch-Hill drag model, followed by the Gidaspow model, with deviations less than 10%.

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Computational Fluid Dynamics Evaluation of the Influence of Cone Geometry on Solids Circulation in Spouted Beds

Cited by 12 publications

References 37 publications

Particle-Scale Study of the Effect of Operating Conditions on Spout Deflection Behavior in a Flat-Bottomed Spout-Fluidized Bed

Particle-Scale Study of the Effect of Operating Conditions on Spout Deflection Behavior in a Flat-Bottomed Spout-Fluidized Bed

Two-Fluid-Model-Based Full Physics Simulations of Mixing in Noncohesive Wet Fluidized Beds

Evaluation of different mathematical models in the CFD-DEM simulation of conical spouted bed fluid dynamics

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