Particle shape effect on bubble dynamics in central air jet pseudo-2D fluidized beds: a CFD-DEM study

Siddhartha Shrestha, Shibo Kuang, Aibing Yu, Zongyan Zhou

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Bubbles considerably influence the characteristics of gas-solid fluidized bed, hence play an important role in determining process performance. This paper presents a CFD-DEM study on the effect of particle shape on the bed microstructure and bubble properties in a pseudo-2D bubbling gas-solid fluidized bed, operated with a continuous central jet. The bubble formation process is successfully generated, where bubbles rise through the bed and burst at the top of the bed. The numerical results show that ellipsoids have slightly different flow patterns from those of spheres. However, the mechanisms of bubble splitting and coalescence are found strongly dependent on particle shape. For spheres, the bubble trajectories mainly follow the bed centreline, whereas the bubbles for ellipsoids are widely distributed on both sides of the bed centreline. This result suggests that the lateral drift of bubbles is high for ellipsoids because such particles prefer to orient their longest major axis in the direction of the fluid flow. At the lower part of the bed, both gas and particle velocity profiles are found axially similar to a Gaussian distribution. In contrast, at the upper part of the bed, their peaks become flatter and broader for ellipsoids. Additionally, the bubble equivalent diameters are higher for ellipsoids while bubbles become more circular for spheres. Both bubble frequency and bubble velocity for ellipsoids are lower than spheres. The results obtained from this study can improve the understanding of bubble dynamics in the fluidization of non-spherical particles.

Original languageEnglish
Pages (from-to)448-466
Number of pages19
JournalChemical Engineering Science
Volume201
DOIs
Publication statusPublished - 29 Jun 2019

Keywords

  • Bubble properties
  • CFD-DEM
  • Ellipsoids
  • Fluidization
  • Single jet

Cite this

@article{5a8010ab8c07426cae3afccce3bae0ef,
title = "Particle shape effect on bubble dynamics in central air jet pseudo-2D fluidized beds: a CFD-DEM study",
abstract = "Bubbles considerably influence the characteristics of gas-solid fluidized bed, hence play an important role in determining process performance. This paper presents a CFD-DEM study on the effect of particle shape on the bed microstructure and bubble properties in a pseudo-2D bubbling gas-solid fluidized bed, operated with a continuous central jet. The bubble formation process is successfully generated, where bubbles rise through the bed and burst at the top of the bed. The numerical results show that ellipsoids have slightly different flow patterns from those of spheres. However, the mechanisms of bubble splitting and coalescence are found strongly dependent on particle shape. For spheres, the bubble trajectories mainly follow the bed centreline, whereas the bubbles for ellipsoids are widely distributed on both sides of the bed centreline. This result suggests that the lateral drift of bubbles is high for ellipsoids because such particles prefer to orient their longest major axis in the direction of the fluid flow. At the lower part of the bed, both gas and particle velocity profiles are found axially similar to a Gaussian distribution. In contrast, at the upper part of the bed, their peaks become flatter and broader for ellipsoids. Additionally, the bubble equivalent diameters are higher for ellipsoids while bubbles become more circular for spheres. Both bubble frequency and bubble velocity for ellipsoids are lower than spheres. The results obtained from this study can improve the understanding of bubble dynamics in the fluidization of non-spherical particles.",
keywords = "Bubble properties, CFD-DEM, Ellipsoids, Fluidization, Single jet",
author = "Siddhartha Shrestha and Shibo Kuang and Aibing Yu and Zongyan Zhou",
year = "2019",
month = "6",
day = "29",
doi = "10.1016/j.ces.2019.02.030",
language = "English",
volume = "201",
pages = "448--466",
journal = "Chemical Engineering Science",
issn = "0009-2509",
publisher = "Pergamon",

}

Particle shape effect on bubble dynamics in central air jet pseudo-2D fluidized beds : a CFD-DEM study. / Shrestha, Siddhartha; Kuang, Shibo; Yu, Aibing; Zhou, Zongyan.

In: Chemical Engineering Science, Vol. 201, 29.06.2019, p. 448-466.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Particle shape effect on bubble dynamics in central air jet pseudo-2D fluidized beds

T2 - a CFD-DEM study

AU - Shrestha, Siddhartha

AU - Kuang, Shibo

AU - Yu, Aibing

AU - Zhou, Zongyan

PY - 2019/6/29

Y1 - 2019/6/29

N2 - Bubbles considerably influence the characteristics of gas-solid fluidized bed, hence play an important role in determining process performance. This paper presents a CFD-DEM study on the effect of particle shape on the bed microstructure and bubble properties in a pseudo-2D bubbling gas-solid fluidized bed, operated with a continuous central jet. The bubble formation process is successfully generated, where bubbles rise through the bed and burst at the top of the bed. The numerical results show that ellipsoids have slightly different flow patterns from those of spheres. However, the mechanisms of bubble splitting and coalescence are found strongly dependent on particle shape. For spheres, the bubble trajectories mainly follow the bed centreline, whereas the bubbles for ellipsoids are widely distributed on both sides of the bed centreline. This result suggests that the lateral drift of bubbles is high for ellipsoids because such particles prefer to orient their longest major axis in the direction of the fluid flow. At the lower part of the bed, both gas and particle velocity profiles are found axially similar to a Gaussian distribution. In contrast, at the upper part of the bed, their peaks become flatter and broader for ellipsoids. Additionally, the bubble equivalent diameters are higher for ellipsoids while bubbles become more circular for spheres. Both bubble frequency and bubble velocity for ellipsoids are lower than spheres. The results obtained from this study can improve the understanding of bubble dynamics in the fluidization of non-spherical particles.

AB - Bubbles considerably influence the characteristics of gas-solid fluidized bed, hence play an important role in determining process performance. This paper presents a CFD-DEM study on the effect of particle shape on the bed microstructure and bubble properties in a pseudo-2D bubbling gas-solid fluidized bed, operated with a continuous central jet. The bubble formation process is successfully generated, where bubbles rise through the bed and burst at the top of the bed. The numerical results show that ellipsoids have slightly different flow patterns from those of spheres. However, the mechanisms of bubble splitting and coalescence are found strongly dependent on particle shape. For spheres, the bubble trajectories mainly follow the bed centreline, whereas the bubbles for ellipsoids are widely distributed on both sides of the bed centreline. This result suggests that the lateral drift of bubbles is high for ellipsoids because such particles prefer to orient their longest major axis in the direction of the fluid flow. At the lower part of the bed, both gas and particle velocity profiles are found axially similar to a Gaussian distribution. In contrast, at the upper part of the bed, their peaks become flatter and broader for ellipsoids. Additionally, the bubble equivalent diameters are higher for ellipsoids while bubbles become more circular for spheres. Both bubble frequency and bubble velocity for ellipsoids are lower than spheres. The results obtained from this study can improve the understanding of bubble dynamics in the fluidization of non-spherical particles.

KW - Bubble properties

KW - CFD-DEM

KW - Ellipsoids

KW - Fluidization

KW - Single jet

UR - http://www.scopus.com/inward/record.url?scp=85062975915&partnerID=8YFLogxK

U2 - 10.1016/j.ces.2019.02.030

DO - 10.1016/j.ces.2019.02.030

M3 - Article

VL - 201

SP - 448

EP - 466

JO - Chemical Engineering Science

JF - Chemical Engineering Science

SN - 0009-2509

ER -