Measurements of voidage profiles in spouted beds

He, Youwei; Lim, C. J.; Grace, John R.; Zhu, Jesse; Qzn, S.-Z.

doi:10.1002/cjce.5450720208

Cited by 125 publications

(134 citation statements)

References 14 publications

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“…For example, Kwauk 35 showed experimentally that the radial solids fraction of FCC catalyst particles in a 90 mm diameter riser decreased from the wall to the axis. This was also observed by He et al 36,37 who measured particle velocity and solids concentration in a spouted bed with a fiber optic probe; and also by Samuelsberg and Hjertager 38 who investigated the flow patterns in a circulating fluidized bed reactor, both numerically and experimentally using laser Doppler anemometry (LDA). In both of these latter studies it was also shown that the particle flux in the axial direction also decreases from the axis to the walls, which means that particles near the wall experience a greater residence time than particles in the bulk phase.…”

Section: Design Overviewsupporting

confidence: 62%

Spouted Bed Electrodes (Sbe) for Direct Utilization of Carbon in Fuel Cells

Calo¹

2004

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Section: Design Overviewsupporting

confidence: 62%

Spouted Bed Electrodes (Sbe) for Direct Utilization of Carbon in Fuel Cells

Calo¹

2004

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“…These results, along with others in the literature, raise a question about the semi-cylindrical spouted bed: are the measurements obtained using the half-bed technique truly representative for inferring the hydrodynamic data for cylindrical beds and, if so, for which variables? The studies by He et al (1994aHe et al ( , 1994b are conclusive regarding the velocity of the solid phase and the porosity of the bed, indicating that special care is necessary when applying this technique. Despite the need for special care, visual information related to the hydrodynamic behavior of the cylindrical bed can only be obtained using the half-column technique.…”

Section: Fig 1 Diagram Of a Semi-cylindrical (Half-column) Spouted Bedmentioning

confidence: 82%

“…They observed that inserting the flat wall into the bed changed the velocity profile of the particles due to the additional system friction caused by the wall. In addition to the above study, He et al (1994b) studied the behavior of the spouted bed porosity profile, comparing the results obtained for cylindrical and semi-cylindrical beds. It was verified that inserting the flat wall did not significantly change the porosity behavior of the bed in comparison with the change caused by the wall on the velocity profile of the solid.…”

Section: Fig 1 Diagram Of a Semi-cylindrical (Half-column) Spouted Bedmentioning

confidence: 99%

“…Béttega et al (2009a) -they evaluated the problem of increase in scale of spouted beds using numerical simulation. The software Fluent® was used to simulate the spouted beds in different scales, respecting the non-dimensional parameters obtained from the work of He et al (1994aHe et al ( , 1994b to ensure the conditions of geometric and dynamic similarity. They used simulation to verify the capacity of the numerical tool to reproduce the increase in the scale when the non-dimensional parameters are maintained.…”

Section: Advances In Cfd Applied To Spouted Bedsmentioning

confidence: 99%

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Use of Fluid Dynamic Simulation to Improve the Design of Spouted Beds

Béttega¹,

Corrêa²,

Freire³

2012

Applied Computational Fluid Dynamics

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“…22 Nevertheless, techniques based on an optical-fiber probe are also promising for this purpose. [23][24][25][26][27][28][29] In recent years, with the development of high performance computers, researchers have used numerical methods to study the flow behavior of fluidized beds. [30][31][32][33][34][35] Computational fluid dynamic (CFD) modeling helps to explain the details of gas-fluidized bed hydrodynamics and allows developing quantitative process models that enable predictive scaling-up and process optimization.…”

mentioning

confidence: 99%

Effect of slip boundary conditions on the simulation of microparticle velocity fields in a conical fluidized bed

2013

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The hydrodynamic performance of micrometric TiO 2 particles has been experimentally studied in a conical fluidized bed and the results compared with numerical simulations. Local solid velocities in the bed have been measured by means of an optical fiber technique under different operating conditions of particle loading and air velocity. The radial profiles of axial solid velocities have been simulated to assess the sensitivity of grid size, and different drag models, namely, those by Syamlal and O'Brien, Ahmadi and Ma, Arastoopour et al., and Gidaspow, for no-slip, partial-slip, and free-slip boundary conditions (BCs). The different drag models record almost similar results, but those provided by the Gidaspow and Ahmadi-Ma models, together with free-slip BCs, are in somewhat better agreement with the experimental data for conical fluidized beds with smooth walls. V C 2013 American Institute of Chemical Engineers AIChE J, 59: [4502][4503][4504][4505][4506][4507][4508][4509][4510][4511][4512][4513][4514][4515][4516][4517][4518] 2013 Keywords: conical fluidized bed, solid velocity, slip boundary conditions, numerical simulation, drag models IntroductionFluidized and spouted beds are extensively used for various industrial applications in pharmaceuticals, 1,2 drying, 3,4 food processing, 5 combustion, 6,7 pyrolysis, and catalytic polymerization. 8,9 A conical fluidized bed has the characteristics of both fluidized and spouted beds, being, therefore, suitable for handling agglomerating or sticky powders. This is particularly the case for the fluidization of fine particles with a wide size distribution corresponding to different groups of Geldart's classification. 10,11 Although many studies have been reported in the literature involving fluidized beds, [12][13][14][15] certain details of the hydrodynamic performance of conical fluidized beds are not fully understood, which is partially due to the few experimental data on the hydrodynamics of these beds. 16,17 Accordingly, the design and scaling-up of conical fluidized beds is not straightforward, given that bed geometry, the ratio of inlet diameter to bed height and operating conditions highly influence gas-solid flow regime. Furthermore, hydrodynamic parameters such as pressure drop, solid volume fraction, and velocity significantly affect the performance of the conical bed. Optimizing the performance of conical fluidized beds requires a thorough understanding of the mixing characteristics and interactions between the gas and solid phases. The standard noninvasive measurement techniques used for the determination of particle trajectories and velocities are as follows: pitot tube, 18 Laser-Doppler anemometry, 19 video technique, 20 radioactive particle tracking, 21 and particle image velocimetry. 22 Nevertheless, techniques based on an optical-fiber probe are also promising for this purpose. [23][24][25][26][27][28][29] In recent years, with the development of high performance computers, researchers have used numerical methods to study the flow behavior of fluidized...

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Measurements of voidage profiles in spouted beds

Cited by 125 publications

References 14 publications

Spouted Bed Electrodes (Sbe) for Direct Utilization of Carbon in Fuel Cells

Spouted Bed Electrodes (Sbe) for Direct Utilization of Carbon in Fuel Cells

Use of Fluid Dynamic Simulation to Improve the Design of Spouted Beds

Effect of slip boundary conditions on the simulation of microparticle velocity fields in a conical fluidized bed

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