start-ver=1.4 cd-journal=joma no-vol=61 cd-vols= no-issue=6 article-no= start-page=1775 end-page=1783 dt-received= dt-revised= dt-accepted= dt-pub-year=2021 dt-pub=20210615 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Effect of Impeller and Gas Stirring on Agglomeration Behavior of Polydisperse Fine Particles in Liquid en-subtitle= kn-subtitle= en-abstract= kn-abstract=Agglomeration, coalescence and flotation of non-metallic inclusions in steel melt are effective for obtaining gclean steel.h 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. en-copyright= kn-copyright= en-aut-name=YamaguchiAkito en-aut-sei=Yamaguchi en-aut-mei=Akito kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=OkanoHitoshi en-aut-sei=Okano en-aut-mei=Hitoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=SumitomoSyunsuke en-aut-sei=Sumitomo en-aut-mei=Syunsuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=UddinMd. Azhar en-aut-sei=Uddin en-aut-mei=Md. Azhar kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KatoYoshiei en-aut-sei=Kato en-aut-mei=Yoshiei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Department of Material and Energy Science, Graduate School of Environmental Science kn-affil= affil-num=3 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=4 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=5 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= en-keyword=agglomeration kn-keyword=agglomeration en-keyword=breakup kn-keyword=breakup en-keyword=particle kn-keyword=particle en-keyword=impeller stirring kn-keyword=impeller stirring en-keyword=gas agitation kn-keyword=gas agitation en-keyword=particle-size-grouping method kn-keyword=particle-size-grouping method END