Abdullaziz Glabe Zakari, Mohammad Mainul Hoque, Peter Ireland, Geoffrey Evans, Subhasish Mitra
{"title":"表面活性剂作用下上升气泡羽流中气体分散动力学","authors":"Abdullaziz Glabe Zakari, Mohammad Mainul Hoque, Peter Ireland, Geoffrey Evans, Subhasish Mitra","doi":"10.1016/j.mineng.2024.109145","DOIUrl":null,"url":null,"abstract":"<div><div>Understanding dispersion behaviour of bubbles emitting from a sparger is a critical element of mineral flotation process. This aspect was investigated in the present study involving a bubble plume in a semi-batch rectangular column in the presence of an anionic surfactant. First, high-speed imaging was used to visualise the bubble plume behaviour at different air flow rates (0.1 – 0.5 L/min). An image processing code was developed to determine the mean bubble diameter which indicated a decrease in the mean bubble diameter from ∼ 0.60 mm to 0.51 mm with increasing gas flow rates. A transient 3D Eulerian-Eulerian multiphase CFD model with a bubble population balance sub-model was also developed to quantify the gas holdup and turbulence energy dissipation rate distribution in this system utilising the experimentally measured mean bubble size. Experimentally, it was observed that symmetry of the bubble plume was disrupted at higher gas flow rates leading to larger dispersion of gas bubbles towards the top of the column. This observation was explained by the CFD model which predicted asymmetric transverse velocity profiles that increased in the axial direction. The model also predicted increasing gas holdup in the system (∼0.02 to 0.11) with increasing gas flow rates. The corresponding turbulence energy dissipation rate increased from ∼ 0.014 to 0.076 m<sup>2</sup>/s<sup>3</sup> with maximum turbulent energy dissipation rate occurring near the gas distributor zone. Also, a transition from a bubbly to a distinct foam zone was noted at the free surface in the higher gas flow rate cases which was explained by the turbulence energy dissipation rate in the system.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":"222 ","pages":"Article 109145"},"PeriodicalIF":4.9000,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Dynamics of gas dispersion in a rising bubble plume in presence of surfactant\",\"authors\":\"Abdullaziz Glabe Zakari, Mohammad Mainul Hoque, Peter Ireland, Geoffrey Evans, Subhasish Mitra\",\"doi\":\"10.1016/j.mineng.2024.109145\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Understanding dispersion behaviour of bubbles emitting from a sparger is a critical element of mineral flotation process. This aspect was investigated in the present study involving a bubble plume in a semi-batch rectangular column in the presence of an anionic surfactant. First, high-speed imaging was used to visualise the bubble plume behaviour at different air flow rates (0.1 – 0.5 L/min). An image processing code was developed to determine the mean bubble diameter which indicated a decrease in the mean bubble diameter from ∼ 0.60 mm to 0.51 mm with increasing gas flow rates. A transient 3D Eulerian-Eulerian multiphase CFD model with a bubble population balance sub-model was also developed to quantify the gas holdup and turbulence energy dissipation rate distribution in this system utilising the experimentally measured mean bubble size. Experimentally, it was observed that symmetry of the bubble plume was disrupted at higher gas flow rates leading to larger dispersion of gas bubbles towards the top of the column. This observation was explained by the CFD model which predicted asymmetric transverse velocity profiles that increased in the axial direction. The model also predicted increasing gas holdup in the system (∼0.02 to 0.11) with increasing gas flow rates. The corresponding turbulence energy dissipation rate increased from ∼ 0.014 to 0.076 m<sup>2</sup>/s<sup>3</sup> with maximum turbulent energy dissipation rate occurring near the gas distributor zone. Also, a transition from a bubbly to a distinct foam zone was noted at the free surface in the higher gas flow rate cases which was explained by the turbulence energy dissipation rate in the system.</div></div>\",\"PeriodicalId\":18594,\"journal\":{\"name\":\"Minerals Engineering\",\"volume\":\"222 \",\"pages\":\"Article 109145\"},\"PeriodicalIF\":4.9000,\"publicationDate\":\"2024-12-05\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Minerals Engineering\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0892687524005740\",\"RegionNum\":2,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"ENGINEERING, CHEMICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Minerals Engineering","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0892687524005740","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, CHEMICAL","Score":null,"Total":0}
Dynamics of gas dispersion in a rising bubble plume in presence of surfactant
Understanding dispersion behaviour of bubbles emitting from a sparger is a critical element of mineral flotation process. This aspect was investigated in the present study involving a bubble plume in a semi-batch rectangular column in the presence of an anionic surfactant. First, high-speed imaging was used to visualise the bubble plume behaviour at different air flow rates (0.1 – 0.5 L/min). An image processing code was developed to determine the mean bubble diameter which indicated a decrease in the mean bubble diameter from ∼ 0.60 mm to 0.51 mm with increasing gas flow rates. A transient 3D Eulerian-Eulerian multiphase CFD model with a bubble population balance sub-model was also developed to quantify the gas holdup and turbulence energy dissipation rate distribution in this system utilising the experimentally measured mean bubble size. Experimentally, it was observed that symmetry of the bubble plume was disrupted at higher gas flow rates leading to larger dispersion of gas bubbles towards the top of the column. This observation was explained by the CFD model which predicted asymmetric transverse velocity profiles that increased in the axial direction. The model also predicted increasing gas holdup in the system (∼0.02 to 0.11) with increasing gas flow rates. The corresponding turbulence energy dissipation rate increased from ∼ 0.014 to 0.076 m2/s3 with maximum turbulent energy dissipation rate occurring near the gas distributor zone. Also, a transition from a bubbly to a distinct foam zone was noted at the free surface in the higher gas flow rate cases which was explained by the turbulence energy dissipation rate in the system.
期刊介绍:
The purpose of the journal is to provide for the rapid publication of topical papers featuring the latest developments in the allied fields of mineral processing and extractive metallurgy. Its wide ranging coverage of research and practical (operating) topics includes physical separation methods, such as comminution, flotation concentration and dewatering, chemical methods such as bio-, hydro-, and electro-metallurgy, analytical techniques, process control, simulation and instrumentation, and mineralogical aspects of processing. Environmental issues, particularly those pertaining to sustainable development, will also be strongly covered.