Details

Autor(en) / Beteiligte

• Shrestha, Siddhartha
• Kuang, Shibo
• Yu, Aibing
• Zhou, Zongyan

Titel

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

Ist Teil von

• Chemical engineering science, 2019-06, Vol.201, p.448-466

Ort / Verlag

Elsevier Ltd

Erscheinungsjahr

2019

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• •Bubble dynamics in gas fluidisation of ellipsoidal particles is studied by CFD-DEM.•Bubbles for ellipsoidal particles have lateral drift phenomenon.•Ellipsoids has larger bubble size than spheres.•Bubble shape for spheres is more circular than ellipsoids.•Bubble rising velocity for ellipsoids is lower than spheres. 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.