Theory of particle segregation in rimming flows of suspensions containing neutrally buoyant particles

2004 ◽  
Vol 16 (3) ◽  
pp. 641-651 ◽  
Author(s):  
Bo Jin ◽  
Andreas Acrivos
Keyword(s):  
Particle Segregation ◽  
Neutrally Buoyant ◽  
Rimming Flows

Stochastic Modelling of Particle Segregation in a Horizontal Drum Mixer

1992 ◽  
Vol 57 (10) ◽  
pp. 2100-2112 ◽  
Author(s):  
Vladimír Kudrna ◽  
Pavel Hasal ◽  
Andrzej Rochowiecki
Keyword(s):  
Differential Equation ◽  
Diffusion Coefficient ◽  
Stochastic Model ◽  
Diffusion Process ◽  
Stochastic Modelling ◽  
Solid Particles ◽  
Kolmogorov Equation ◽  
Particle Segregation ◽  
Drum Mixer ◽  
Horizontal Drum

A process of segregation of two distinct fractions of solid particles in a rotating horizontal drum mixer was described by stochastic model assuming the segregation to be a diffusion process with varying diffusion coefficient. The model is based on description of motion of particles inside the mixer by means of a stochastic differential equation. Results of stochastic modelling were compared to the solution of the corresponding Kolmogorov equation and to results of earlier carried out experiments.

scholarly journals Influence of center gas supply device on gas–solid flow in COREX shaft furnace through DEM–CFD model

2020 ◽  
Vol 18 (5-6) ◽  
Author(s):  
Heng Zhou ◽  
Shuyu Wang ◽  
Binbin Du ◽  
Mingyin Kou ◽  
Zhiyong Tang ◽  
...  
Keyword(s):  
Gas Flow ◽  
Shaft Furnace ◽  
Middle Zone ◽  
Cfd Model ◽  
Gas Velocity ◽  
Gas Distribution ◽  
Particle Segregation ◽  
Solid Flow ◽  
Corex Shaft Furnace ◽  
Gas Supply

AbstractIn order to develop the central gas flow in COREX shaft furnace, a new installment of center gas supply device (CGD) is designed. In this work, a coupled DEM–CFD model was employed to study the influence of CGD on gas–solid flow in COREX shaft furnace. The particle descending velocity, particle segregation behaviour, void distribution and gas distribution were investigated. The results show that the CGD affects the particles descending velocity remarkably as the burden falling down to the slot. Particle segregation can be observed under the inverse ‘V’ burden profile, and the influence of CGD on the particle segregation is unobvious on the whole, which causes the result that the voidage is slightly changed. Although the effect of CGD on solid flow is not significant, the gas flow in shaft furnace has an obvious change. Compared with the condition without CGD, in the case with CGD, the gas velocity is improved significantly, especially in the middle zone of the furnace, which further promotes the center gas distribution. Meanwhile, the pressure drop in the furnace with the installation of CGD is increased partly.

scholarly journals Remarkable simplicity in the prediction of nonspherical particle segregation

2020 ◽  
Vol 2 (4) ◽  
Author(s):  
Ryan P. Jones ◽  
Julio M. Ottino ◽  
Paul B. Umbanhowar ◽  
Richard M. Lueptow
Keyword(s):  
Particle Segregation ◽  
Nonspherical Particle

Dispersion of Neutrally Buoyant Horizontal Round Jet in Wave Environment

2005 ◽  
Vol 131 (12) ◽  
pp. 1088-1097 ◽  
Author(s):  
Yonguk Ryu ◽  
Kuang-An Chang ◽  
Nobuhito Mori
Keyword(s):  
Round Jet ◽  
Neutrally Buoyant

Alumina-Titania Spot Spraying Bead Formation and Characteristics in Atmospheric Plasma Spraying

2007 ◽  
Vol 534-536 ◽  
pp. 401-404
Author(s):  
Hye Sook Joo ◽  
Han Shin Choi ◽  
Hyung Ho Jo ◽  
Hoon Cho ◽  
June Seob Kim ◽  
...  
Keyword(s):  
Deposition Rate ◽  
Mass Flux ◽  
Deposition Efficiency ◽  
Atmospheric Plasma Spraying ◽  
Atmospheric Plasma ◽  
Gas Composition ◽  
Particle Segregation ◽  
Rate Maximum ◽  
The Moment ◽  
Short Time

Fine and coarse alumina-titania composite particles were overlaid by allowing the particles to be deposited for a short time without moving a plasmatron [spot spraying bead]. Both the deposition efficiency and maximum deposition rate were measured at the different plasma gas composition. Considering the normalized maximum deposition rate [(maximum deposition rate)x(deposition efficiency)-1], effects of particle size and plasma gas composition on the particle segregation within a cross-section of mass flux could be estimated. Also, particle melting state according to the position within a mass flux at the moment of impact could be also estimated through the investigations of microstructure and phase composition of the spot spraying bead.

scholarly journals Hydrodynamic Boundary Layers at Solid Wall—A Tool for Separation of Fine Solids

2021 ◽  
Vol 5 (1) ◽  
pp. 11
Author(s):  
Ljubomir Nikolov
Keyword(s):  
Relative Density ◽  
Hydrodynamic Interaction ◽  
Theoretical Study ◽  
Solid Wall ◽  
Separation Processes ◽  
Starting Point ◽  
Potential Applications ◽  
Neutrally Buoyant ◽  
Solid Walls ◽  
Solid Spheres

A theoretical study is performed about the hydrodynamic interaction of fine species entrapped in the boundary layer (BL) at solid wall (plate). The key starting point is the analysis of the disturbance introduced by solid spheres in the background fluid flow. For a neutrally buoyant entity, the type of interaction is determined by the size of the spheres as compared to the thickness of the BL region. The result is granulometric separation of the solids inside the BL domain at the wall. The most important result in view of potential applications concerns the so-called small particles Rp < L/ReL5/4 (ReL is the Reynolds number of the background flow and Rp is the radius of the entrapped sphere). In the case of non-neutrally buoyant particles, gravity interferes with the separation effect. Important factor in this case is the relative density of the solid species as compared to this of the fluid. In view of further practical uses, particles within the range of Δρ/ρ < Fr2/ReL1/2 (Fr is Froude number and Δρ/ρ is the relative density of the entrapped solids) are systematically studied. The trajectories inside the BL region of the captured species are calculated. The obtained data show that there are preferred regions along the wall where the fine solids are detained. The results are important for the assessment of the general efficiency of entrapment and segregation of fine species in the vicinity of solid walls and have high potential for further design of industrial separation processes.

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