Effect of impeller and gas stirring on agglomeration behavior of polydisperse fine particles in liquid

Akito Yamaguchi, Hitoshi Okano, Syunsuke Sumitomo, Md Azhar Uddin, Yoshiei Kato

Research output: Contribution to journalArticlepeer-review

Abstract

Agglomeration, coalescence and flotation of non-metallic inclusions in steel melt are effective for obtaining “clean steel.” In this study, the agglomeration and breakup behaviors of particles with a primary particle size distribution (hereinafter, polydisperse particles) in a liquid under impeller and gas stirring were compared by numerical calculations and model experiments. The particle-size-grouping (PSG) method in the numerical agglomeration model of particles was combined with a breakup term of agglomeration due to bubble bursting at the free surface. Polydisperse and monodisperse polymethylmethacrylate (PMMA) particles were used in the agglomeration experiments. The agglomeration rate of the polydisperse particles under impeller stirring was increased by an increasing energy input rate, whereas the agglomeration rate under gas stirring decreased under this condition due to the larger contribution of the breakup of agglomerated particles during bubble bursting in gas stirring. At the same energy input rate, agglomeration of polydisperse particles was larger under impeller stirring than under gas stirring. The agglomeration rate of polydisperse particles was larger than that of monodisperse particles under both impeller and gas stirring at the same energy input rate. The computational temporal changes in the total number of particles were in good agreement with the experimental results. This means that the difference in the agglomeration behaviors observed in impeller and gas stirring can be explained by the turbulent coagulation and subsequent agglomerated particle breakup in gas stirring. The computational temporal change in the number of each group approximately agreed with the experimental change in both impeller and gas stirring.

Original languageEnglish
Pages (from-to)1775-1783
Number of pages9
Journalisij international
Volume61
Issue number6
DOIs
Publication statusPublished - 2021

Keywords

  • Agglomeration
  • Breakup
  • Gas agitation
  • Impeller stirring
  • Particle
  • Particle-size-grouping method

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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