Characterization of channelling in multiphase systems. Application to a liquid fluidized bed of angular Biobone particles

Briens, Lauren; Briens, Cédric; Margaritis, Argyrios; Cooke, S.L.; Bergougnou, M.A.

doi:10.1016/s0032-5910(96)03206-8

Cited by 11 publications

(3 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, channelling can be observed in some applications of fluid bed reactors. Channelling is a condition wherein the fluid passes through the bed along localized paths [11]. This phenomenon should be avoided due to its adverse effects.…”

Section: Introductionmentioning

confidence: 99%

Localized fluidization in granular materials: Theoretical and numerical study

et al. 2016

View full text Add to dashboard Cite

We present analytical and numerical results on localized fluidization within a granular layer subjected to a local injection of fluid. As the injection rate increases the three different regimes previously reported in the literature are recovered: homogeneous expansion of the bed, fluidized cavity in which fluidization starts developing above the injection area, and finally the chimney of fluidized grains when the fluidization zone reaches the free surface. The analytical approach is at the continuum scale, based on Darcy's law and Therzaghi's effective stress principle. It provides a good description of the phenomenon as long as the porosity of the granular assembly remains relatively homogeneous, i.e., for small injection rates. The numerical approach is at the particle scale based on the coupled discrete element method and a pore-scale finite volume method. It tackles the more heterogeneous situations which occur at larger injection rates. The results from both methods are in qualitative agreement with data published independently. A more quantitative agreement is achieved by the numerical model. A direct link is evidenced between the occurrence of the different regimes of fluidization and the injection aperture. While narrow apertures let the three different regimes be distinguished clearly, larger apertures tend to produce a single homogeneous fluidization regime. In the former case, it is found that the transition between the cavity regime and the chimney regime for an increasing injection rate coincides with a peak in the evolution of inlet pressure. Finally, the occurrence of the different regimes is defined in terms of the normalized flux and aperture.

show abstract

Section: Introductionmentioning

confidence: 99%

Localized fluidization in granular materials: Theoretical and numerical study

et al. 2016

View full text Add to dashboard Cite

show abstract

“…By contrast, few studies have focused on partial fluidization generated by a localized fluid flow even if several industrial processes are directly concerned with such situations as spouted beds [6,7], tapered beds [8], or specific fluidizers designed for maintenance of navigable waterways and sand bypassing [9]. The existence of fluid escape structures is also widely encountered in natural geological formations [10][11][12][13][14] and in some undesired problematic cases including channelling in fluidized reactors [15] and expansion, possibly leading to collapse, of underground cavities in the vicinity of a leaking buried pipeline [16] and in the foundation of an embankment dam subject to seepage flow [17,18]. That last example is of high relevance in the general context of dyke and dam safety since one of the two main threats of such hydraulic structures is internal erosion, a generic term covering four identified mechanisms of soil erosion within an embankment dam, or its foundations, under the action of infiltration water flows [17,18].…”

Section: Introductionmentioning

confidence: 99%

Two-dimensional numerical simulation of chimney fluidization in a granular medium using a combination of discrete element and lattice Boltzmann methods

Ngoma¹,

Philippe²,

Bonelli³

et al. 2018

Phys. Rev. E

View full text Add to dashboard Cite

We present here a numerical study dedicated to the fluidization of a submerged granular medium induced by a localized fluid injection. To this end, a two-dimensional (2D) model is used, coupling the lattice Boltzmann method (LBM) with the discrete element method (DEM) for a relevant description of fluid-grains interaction. An extensive investigation has been carried out to analyze the respective influences of the different parameters of our configuration, both geometrical (bed height, grain diameter, injection width) and physical (fluid viscosity, buoyancy). Compared to previous experimental works, the same qualitative features are recovered as regards the general phenomenology including transitory phase, stationary states, and hysteretic behavior. We also present quantitative findings about transient fluidization, for which several dimensionless quantities and scaling laws are proposed, and about the influence of the injection width, from localized to homogeneous fluidization. Finally, the impact of the present 2D geometry is discussed, by comparison to the real three-dimensional (3D) experiments, as well as the crucial role of the prevailing hydrodynamic regime within the expanding cavity, quantified through a cavity Reynolds number, that can presumably explain some substantial differences observed regarding upward expansion process of the fluidized zone when the fluid viscosity is changed.

show abstract

“…9-4b) and the different scales, despite the two reactors being geometrically similar. decreased, which could be due to liquid channeling at higher velocities [260,278] leading to poor fluidization of GAC or particle entrainment reducing the overall concentration of GAC. This further highlights the need for real-time monitoring of the process.…”

Section: Eastmentioning

confidence: 99%

Experimental investigation on membrane fouling mitigation by solid-liquid fluidization

Wang¹

View full text Add to dashboard Cite

First of all, I would like to express my sincere appreciation to my main supervisor Assistant Professor Chew Jia Wei. Thank her for accepting me as a PhD student, and giving me the opportunity to conduct this research work. Without her invaluable guidance, support, supervision and encouragement, my research works cannot go through smoothly. Inspired by her spirits, I can then plunge into my work with immense zeal. And I also want to express my sincere gratitude to my co-supervisors Professor Anthony Gordon Fane and Professor Liu Yu for giving the crucial advices and sharing their research experiences, all of which steer my research work in a promising direction. I cordially thank my mentor Professor Wang Rong for her kind supports and encouragement. Secondly, I would like to acknowledge the Interdisciplinary Graduate School (IGS) and Nanyang Environment and Water Research Institute (NEWRI) for funding my PhD scholarship. Thank Singapore Membrane Technology Centre (SMTC) and School of Chemical and Biomedical Engineering (SCBE) for the research funding support. Moreover, this study is also supported by

show abstract

Characterization of channelling in multiphase systems. Application to a liquid fluidized bed of angular Biobone particles

Cited by 11 publications

References 12 publications

Localized fluidization in granular materials: Theoretical and numerical study

Localized fluidization in granular materials: Theoretical and numerical study

Two-dimensional numerical simulation of chimney fluidization in a granular medium using a combination of discrete element and lattice Boltzmann methods

Experimental investigation on membrane fouling mitigation by solid-liquid fluidization

Contact Info

Product

Resources

About