Micromechanic modeling and analysis of the flow regimes in horizontal pneumatic conveying

Kuang, Shibo; Yu, Aibing

doi:10.1002/aic.12480

Cited by 72 publications

(25 citation statements)

References 76 publications

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“…ese phenomena are similar to the observations reported in the experimental work of Wypych and Yi [42] and the simulation study by Kuang and Yu [43]. Figure 14 shows the distribution of time-averaged solids concentration and porosity when a dune passes through the stepped section.…”

Section: Mechanisms Governing Solid Dune/pressure Surge Phenomenasupporting

confidence: 84%

Computational Study of Gas‐Solid Flow in a Horizontal Stepped Pipeline

Chu

Pan

et al. 2019

Mathematical Problems in Engineering

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In this paper, the mechanism governing the particle-fluid flow characters in the stepped pipeline is studied by the combined discrete element method (DEM) and computational fluid dynamics (CFD) model (CFD-DEM) and the two fluid model (TFM). The mechanisms governing the gas-solid flow in the horizontal stepped pipeline are investigated in terms of solid and gas velocity distributions, pressure drop, process performance, the gas-solid interaction forces, solid-solid interaction forces, and the solid-wall interaction forces. The two models successfully capture the key flow features in the stepped pipeline, such as the decrease of gas velocity, solid velocity, and pressure drop, during and after the passage of gas-solid flow through the stepped section. What is more important, the reason of the appearance of large size solid dune and pressure surge phenomena suffered in the stepped pipeline is investigated macroscopically and microscopically. The section in which the blockage problem most likely occurs in the stepped pipeline is confirmed. The pipe wall wearing problem, which is one of the most common and critical problems in pneumatic conveying system, is analysed and investigated in terms of interaction forces. It is shown that the most serious pipe wall wearing problem happened in the section which is just behind the stepped part.

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Section: Mechanisms Governing Solid Dune/pressure Surge Phenomenasupporting

confidence: 84%

Computational Study of Gas‐Solid Flow in a Horizontal Stepped Pipeline

Chu

Pan

et al. 2019

Mathematical Problems in Engineering

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“…τ and ε f are the fluid viscous stress tensor and porosity, respectively, which are given as

τ = μ_{normale} [(\nabla u) + {(\nabla u)}^{- 1}]

and

ε_{normalf} = 1 - (\sum_{i = 1}^{k_{V}} V_{i}) / Δ V

, where V i is the volume of particle i (or part of the volume if the particle is not fully in the CFD cell), k V is the number of particles in the CFD cell, and μ e the fluid effective viscosity determined by k ‐ ε turbulent model, which has been used in our previous work . Note that the effect of gas turbulence on solid flow has been tested, and it is found that the effect can be ignored for coarse particles . However, further tests are needed to justify if this treatment can be applied to fine particles.…”

Section: Model Descriptionmentioning

confidence: 99%

CFD–DEM modeling of gas fluidization of fine ellipsoidal particles

Gan

Zhou

2015

AIChE Journal

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in Wiley Online Library (wileyonlinelibrary.com)Particle characteristics are important factors affecting gas fluidization. In this work, the effects of both particle size and shape on fluidization in different flow regimes are studied using the combined computational fluid dynamic-discrete element method approach. The results are first analyzed in terms of flow patterns and fluidization parameters such as pressure drop, minimum fluidization, and bubbling velocities. The results show that with particle size decreasing, agglomerates can be formed for fine ellipsoidal particles. In particular, "chain phenomenon," a special agglomerate phenomenon exists in expanded and fluidized beds for fine prolate particles, which is caused by the van der Waals force. The minimum fluidization velocity increases exponentially with the increase of particle size, and for a given size, it shows a "W" shape with aspect ratio. A correlation is established to describe the dependence of minimum fluidization velocity on particle size and shape. Ellipsoids have much higher minimum bubbling velocities and fluidization index than spheres. V C 2015 American Institute of Chemical Engineers AIChE J, 62: 62-77, 2016

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“…The model could then successfully reproduce various flow patterns. Kuang and Yu [19] could predict the various flow regimes in 3D horizontal pneumatic conveying. However, they did not consider gas phase turbulence alteration due to the presence of the dispersed phase.…”

Section: Introductionmentioning

confidence: 99%