Particle Mixing near the Grid Region of Fluidized Beds

Wen, C. Y.; Krishnan, R.P.; Kalyanaraman, R.

doi:10.1007/978-1-4684-1045-7_41

Cited by 7 publications

(4 citation statements)

References 1 publication

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“…stainless-steel column. In both columns, the fluidizing gas was fed through a bubble cap distributor designed according to the recommendations of Wen et al (1980). In addition, ports were located at various axial positions of these columns to allow insertion of pressure and capacitance probes.…”

Section: Methodsmentioning

confidence: 99%

Characterization of the Flow Transition between Bubbling and Turbulent Fluidization

Chehbouni¹,

Chaouki²,

Guy³

et al. 1994

Ind. Eng. Chem. Res.

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Section: Methodsmentioning

confidence: 99%

Characterization of the Flow Transition between Bubbling and Turbulent Fluidization

Chehbouni¹,

Chaouki²,

Guy³

et al. 1994

Ind. Eng. Chem. Res.

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“…For dilute flow, the drag coefficient β is given as (Wen, 1966)

\beta =\frac{3}{4}\frac{\left(1-{\phi }_{f}\right){\phi }_{f}}{D}\rho \vert \mathbf{u}-\mathbf{v}\vert {C}_{D0}{\phi }_{f}^{-2.7},

…”

Section: Methodsmentioning

confidence: 99%

Particle Nonresolved DNS‐DEM Study of Flocculation Dynamics of Cohesive Sediment in Homogeneous Isotropic Turbulence

Balachandar

2022

Water Resources Research

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Cohesive sediment transport is important for many geophysical and engineering applications, for example, the rapid siltation in navigation channels and harbors (Hayter & Mehta, 1986;Winterwerp et al., 2000), cohesive sediment transport in salt marsh (Graham & Manning, 2007) and long-term delta morphology (Edmonds & Slingerland, 2010). Cohesive sediment can absorb pollutants (e.g., heavy metals, pesticides and nutrients) and is a concern for water quality (Ongley et al., 1992). Modeling suspended sediment dynamics is also essential for the understanding of biogeochemical cycles. Transport of estuarine and nearshore cohesive sediment therefore plays an important role in coastal processes and the functioning of healthy ecosystems (Grabowski et al., 2011;Deegan et al., 2012). Settling velocity is one of the key parameters in sediment transport. Cohesive sediment can bind together to form flocs and large flocs can breakup by shear. A floc size distribution often develops in sediment suspension and flocs of different size will settle at different velocities. The settling velocity of cohesive sediment strongly depends on the flocculation dynamics (Winterwerp & Van Kesteren, 2004). However, due to complex surface physico-chemical and biological properties of cohesive sediment, cohesive sediment dynamics are complex and empirically parameterized (Winterwerp et al., 2006;Kuprenas et al., 2018). It is fundamentally important to understand the cohesive sediment dynamics in natural environment, in particular how flow turbulence affects the flocculation dynamics, and hence the floc size distribution and the settling velocity.Flocculation plays an important role in cohesive sediment transport. To represent flocculation of cohesive sediment more realistically, models based on either characteristic floc diameter (Winterwerp, 1998;Son & Hsu, 2008) or size-classes (McAnally & Mehta, 2002;Maerz et al., 2011) have been developed. Models based on the characteristic floc diameter simply assume flocs to have a single equilibrium size, which can either be derived from a single-class population balance equation or empirical equations (Maggi, 2009). Kuprenas et al. (2018) improved the Winterwerp model (Winterwerp, 1998) to consider the upper limit on floc size due to turbulent shear. However, bimodal floc size distribution (FSD) with the first peak around microflocs by direct contact

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“…The region of slow-moving or stagnant material near the gas distributor is called the dead zone. Wen et al 19 reported that the dead zone consists of three parts in the axial direction from the surface of gas distributor. The first one is a stagnant volume of material positioned directly on the top of distributor.…”

Section: Simulation Setupmentioning

confidence: 99%

Effect of Gas Distributor on Hydrodynamics and the Rochow Reaction in a Fluidized Bed Membrane Reactor

Zhang

Liu

et al. 2016

Ind. Eng. Chem. Res.

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Gas distributor configurations were optimized for the direct synthesis of methychlorosilanes in a fluidized bed membrane reactor. The Syamlal−O'Brien drag model was optimized to allow reasonable prediction of solid volume fraction, and the influences of opening area ratio and the number of holes of gas distributor on hydrodynamics were investigated by computational fluid dynamics simulation. The results indicated that a gas distributor with a 0.53% opening area ratio and 19 holes exhibited a steadier radial solid volume fraction distribution and lower dead zone area ratio. The effects of gas distributor configuration on the Rochow reaction were also tested experimentally, and dimethydichlorosilane selectivity and silicon conversion were both increased. This suggested that the hydrodynamic behavior using a gas distributor with Φ = 0.53% and n = 19 is beneficial for a well-distributed heat-transfer coefficient. Consequently, Φ = 0.53% and n = 19 were proposed as the best gas distributor configuration, and the reaction yield was 7.3% higher.

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Particle Mixing near the Grid Region of Fluidized Beds

Cited by 7 publications

References 1 publication

Characterization of the Flow Transition between Bubbling and Turbulent Fluidization

Characterization of the Flow Transition between Bubbling and Turbulent Fluidization

Particle Nonresolved DNS‐DEM Study of Flocculation Dynamics of Cohesive Sediment in Homogeneous Isotropic Turbulence

Effect of Gas Distributor on Hydrodynamics and the Rochow Reaction in a Fluidized Bed Membrane Reactor

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