Flow Patterns and Transitions of a Novel Annular Spouted Bed with Multiple Air Nozzles

Hu, Guoxin; Gong, Xiwu; Wei, Bingnan; Li, Yanhong

doi:10.1021/ie800733n

Cited by 16 publications

(6 citation statements)

References 24 publications

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“…In addition, many experimental and theoretical studies, which aimed at grasping the more useful flow characteristics of the spouted beds, have also been performed (Hu et al, 2008). The vertical two-phase fluid-solids flow ( Fig.…”

Section: Background Of Heterogeneous Systemsmentioning

confidence: 99%

Hydrodynamics and Mass Transfer in Heterogeneous Systems

Garić‐Grulović¹,

Bošković‐Vragolović²,

Grbavčić³

et al. 2011

Advanced Topics in Mass Transfer

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Section: Background Of Heterogeneous Systemsmentioning

confidence: 99%

Hydrodynamics and Mass Transfer in Heterogeneous Systems

Garić‐Grulović¹,

Bošković‐Vragolović²,

Grbavčić³

et al. 2011

Advanced Topics in Mass Transfer

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“…To overcome this issue, the alignment of several interconnected chambers in parallel holds much promise for scaling up capacity. Several experimental and numerical reports have investigated the scale‐up of other types of spouting apparatus, such as the multiple spouted bed with multiple spouting inlet, the annular spouted bed with multiple air nozzles, the conically spouted bed, flat‐bottom spouted bed, and the slot‐rectangular spouted bed . Although these reports did not focus specifically on the spout‐fluid bed, the results collectively demonstrate that the presence of several inlets leads to significant interactions between chambers.…”

Section: Introductionmentioning

confidence: 99%

CFD–DEM investigation into the scaling up of spout‐fluid beds via two interconnected chambers

et al. 2016

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The hydrodynamics and chamber interaction in a three-dimensional spout-fluid bed with two interconnected chambers are investigated via computational fluid dynamics coupled with discrete element method (CFD-DEM), because multiple interconnected chambers are key to scaling up spout-fluid beds. The overall solid motion, spouting evolution, and spoutannulus interface is studied, followed by time-averaged hydrodynamics, particle-scale information, spout-annulus interaction, and inter-chamber interaction. The results show that inter-chamber interactions lead to unique characteristics distinct from that for a single-chamber system, including (1) asymmetry of the hydrodynamics within each chamber, (2) alternative spouting behavior in the two chambers, (3) smaller pressure drop in terms of magnitude and fluctuations, (4) two peaks in the solid residence time (SRT) frequency histogram of the annulus, (5) average SRT in the spout is twice that in a single-chamber, and (6) larger solid dispersion in all three directions. The results provide meaningful understanding for the scale-up of spout-fluid beds.In view of its excellent performance and widespread application, numerous experimental efforts have unsurprisingly focused on various aspects of this apparatus, spanning the hydrodynamics, 11,12 solid circulation, 13,14 particle velocity profile, 15 pressure drop 16 and fluctuation, 17 flow reigme, 18-20 maximum bed height, 21 particle mixing, 22 minimum spouting velocity, 23 effect of draft plates, 24-26 thermal behavior, 27 and so on. In tandem with experimental investigations, the numerical simulation of the dense two-phase flow has progressed too. As is well-acknowledged, two approaches, namely, the twofluid model (TFM) and computational fluid dynamics combined with discrete element method (CFD-DEM), are available to model the dense gas-solid flow. 28,29 The critical difference between these two approaches lies in the resolution of the solid motion: the solid phase is treated as a continuum and tracked individually in the Lagrangian framework in TFM and CFD-DEM, respectively. Zhong et al. 30 numerically explored the gas/solid flow in the three-dimensional (3-D) spout-fluid bed using TFM, wherein the kinetic theory of granular flow provided the closures. The results demonstrated that the simulation results are strongly affected by the restitution

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“…Saidutta et al [16] used the 'spout mixing number' to explain the extent of mixing flow volume in a continuously operated multiple spouted bed. To enhance particle flow and eliminate stagnation in the annular space, Hu et al [17,18] proposed a novel multiple-nozzle spouted bed and investigated the spoutable bed height, flow pattern and particle mixing characteristics.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Mixing and Mixing Rate in a Multiple Spouted Bed by Image Processing Technique

Zhang

Wang

Xiao

et al. 2017

International Journal of Chemical Reactor Engineering

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A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. AbstractMixing efficiency is one of the most significant factors, affecting both performance and scale-up of a gas-solid reactor system. This paper presents an experimental investigation on the particle mixing in a multiple spouted bed. Image processing technique was used to extract the real-time information concerning the distribution of particle components (bed materials and tracer particles). A more accurate definition of the tracer concentration was developed to calculate the mixing index. According to the visual observation and image analysis, the mixing mechanism was revealed and the mixing rate was evaluated. Based on these results, the effects of operation parameters on the mixing rate were discussed in terms of the flow patterns. It is found that the detection of the pixel distribution of each component in RGB images is not affected by the interference of air void, thus maintaining good measurement accuracy. Convective transportation controls the particle mixing in the internal jet and spout, while shear dominants the particle mixing in the dense moving region. Global mixing takes place only when the path from one spout cell to the other is open. This path can be formed either by the bubbles or particle circulation flows. The mixing rate is linked to the bubble motion and particle circulation. Provided that there are interactions between the spout cells, any parameters promoting the bubble motion and circulation can increase the mixing rate. Finally, a mixing pattern diagram was constructed to establish the connection between the flow structure and mixing intensity.

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Flow Patterns and Transitions of a Novel Annular Spouted Bed with Multiple Air Nozzles

Cited by 16 publications

References 24 publications

Hydrodynamics and Mass Transfer in Heterogeneous Systems

Hydrodynamics and Mass Transfer in Heterogeneous Systems

CFD–DEM investigation into the scaling up of spout‐fluid beds via two interconnected chambers

Evaluation of Mixing and Mixing Rate in a Multiple Spouted Bed by Image Processing Technique

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