DEM simulation of cake formation in sedimentation and filtration / K. J. Dong in Minerals engineering, Vol. 22 N° 11 (Octobre 2009)  

Public ISBD [article]  inMinerals engineering > Vol. 22 N° 11 (Octobre 2009) . - pp. 921–930 Titre : DEM simulation of cake formation in sedimentation and filtration Type de document : texte imprimé Auteurs : K. J. Dong, Auteur ; R. P. Zou, Auteur ; R.Y. Yang, Auteur Année de publication : 2009 Article en page(s) : pp. 921–930 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Liquid–solid separation Sedimentation Filtration Particle packing Discrete element method Résumé : This paper presents a DEM study of cake formation and growth in sedimentation and filtration processes with constant flow rate or pressure. The liquid flow is assumed to be one-dimensional and the motion of particles is three-dimensional. Various forces are included to determine the motion of particles, including the particle–particle contact forces, the van der Waals force and the particle–fluid interactions such as buoyancy, drag and lift forces. The effects of the material properties of particles and liquid and the operational conditions are examined. The structures of cakes are also analysed and the relationship between cake porosity and interparticle force is quantified. The microscopic analysis demonstrates that these variables affect the process and the cake structures through their effects on the gravity or cohesive force, which competes in controlling the formation of a cake. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001010 [article] DEM simulation of cake formation in sedimentation and filtration [texte imprimé] / K. J. Dong, Auteur ; R. P. Zou, Auteur ; R.Y. Yang, Auteur . - 2009 . - pp. 921–930. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 11 (Octobre 2009) . - pp. 921–930 Mots-clés : Liquid–solid separation Sedimentation Filtration Particle packing Discrete element method Résumé : This paper presents a DEM study of cake formation and growth in sedimentation and filtration processes with constant flow rate or pressure. The liquid flow is assumed to be one-dimensional and the motion of particles is three-dimensional. Various forces are included to determine the motion of particles, including the particle–particle contact forces, the van der Waals force and the particle–fluid interactions such as buoyancy, drag and lift forces. The effects of the material properties of particles and liquid and the operational conditions are examined. The structures of cakes are also analysed and the relationship between cake porosity and interparticle force is quantified. The microscopic analysis demonstrates that these variables affect the process and the cake structures through their effects on the gravity or cohesive force, which competes in controlling the formation of a cake. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001010

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Discrete particle simulation of particle flow in a stirred mill / C.T. Jayasundara in Industrial & engineering chemistry research, Vol. 51 N° 2 (Janvier 2012)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 51 N° 2 (Janvier 2012) . - pp. 1050-1061 Titre : Discrete particle simulation of particle flow in a stirred mill : Effect of mill properties and geometry Type de document : texte imprimé Auteurs : C.T. Jayasundara, Auteur ; R.Y. Yang, Auteur ; A. B. Yu, Auteur Année de publication : 2012 Article en page(s) : pp. 1050-1061 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Solids flow Résumé : Particle flow in a stirred mill was modeled using discrete element method, focusing on the effect of mill properties and stirrer configurations, such as particle-wall friction, the size of disc holes, distance between stirrers, and stirrer shape, on the flow properties of grinding media. The flow properties were analyzed in terms ofvelocity field, porosity distribution, collision frequency, collision energy, impact energy, and power draw. The results indicate that although particle-wall sliding friction coefficient affects the energy transfer from discs to particles, too high a sliding friction may lead to a decrease in energy efficiency. The distance between discs significantly affects the circulation of grinding media between discs. Among the different stirrer types considered, energy transfer is more effective when disc holes are present. Pin stirrer shows increased grinding rates which also results in relatively high power consumption. Although different collision environments exist with different stirrer types, it is shown that the grinding rate can be determined by the first-order kinetics where the rate constant is dependent on the impact energy, for a given material. Grinding efficiency has been compared for different grinding materials under different operating conditions. The results suggest that selection of stirrer geometry also depends on the feed size and the type of material to be ground. Discussion has also been made of the usefulness of particle scale information in the design and control of stirred mills of different types. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25476438 [article] Discrete particle simulation of particle flow in a stirred mill : Effect of mill properties and geometry [texte imprimé] / C.T. Jayasundara, Auteur ; R.Y. Yang, Auteur ; A. B. Yu, Auteur . - 2012 . - pp. 1050-1061. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 2 (Janvier 2012) . - pp. 1050-1061 Mots-clés : Solids flow Résumé : Particle flow in a stirred mill was modeled using discrete element method, focusing on the effect of mill properties and stirrer configurations, such as particle-wall friction, the size of disc holes, distance between stirrers, and stirrer shape, on the flow properties of grinding media. The flow properties were analyzed in terms ofvelocity field, porosity distribution, collision frequency, collision energy, impact energy, and power draw. The results indicate that although particle-wall sliding friction coefficient affects the energy transfer from discs to particles, too high a sliding friction may lead to a decrease in energy efficiency. The distance between discs significantly affects the circulation of grinding media between discs. Among the different stirrer types considered, energy transfer is more effective when disc holes are present. Pin stirrer shows increased grinding rates which also results in relatively high power consumption. Although different collision environments exist with different stirrer types, it is shown that the grinding rate can be determined by the first-order kinetics where the rate constant is dependent on the impact energy, for a given material. Grinding efficiency has been compared for different grinding materials under different operating conditions. The results suggest that selection of stirrer geometry also depends on the feed size and the type of material to be ground. Discussion has also been made of the usefulness of particle scale information in the design and control of stirred mills of different types. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25476438

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Effect of slurry properties on particle motion in IsaMills / C.T. Jayasundara in Minerals engineering, Vol. 22 N° 11 (Octobre 2009)  

Public ISBD [article]  inMinerals engineering > Vol. 22 N° 11 (Octobre 2009) . - pp. 886–892 Titre : Effect of slurry properties on particle motion in IsaMills Type de document : texte imprimé Auteurs : C.T. Jayasundara, Auteur ; R.Y. Yang, Auteur ; B.Y. Guo, Auteur Année de publication : 2009 Article en page(s) : pp. 886–892 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Mineral processing Discrete element method Computational fluid dynamics IsaMill™ Stirred mill Résumé : IsaMill™ is a high-speed stirred mill for a range of milling duties from ultra-fine to relatively coarse grinding in the mineral processing industry. This work investigated particle and slurry flow in a mill using a combined Discrete Element Method and Computational Fluid Dynamics (DEM-CFD) approach. Slurry properties, such as flow density and viscosity, were varied to study their effects on the flow properties in terms of flow velocity, power draw, collision frequency, collision energy and total impact energy. Significant differences were observed when slurry was introduced and other conditions unchanged. With increasing density, fluid and particle flows showed stronger circulation in the axial direction due to the larger drag forces. Increased relative velocity and interaction between particles with disc led to higher collision frequency and collision energy. Increase in flow viscosity limited particles from moving towards the outer wall and the particles were more dispersed due to the larger circulating velocity in the axial direction. The total impact energy of the media and power draw also increase with slurry density and viscosity. The developed model provides a useful framework for further analysis of particle–slurry interactions in IsaMills™. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001162 [article] Effect of slurry properties on particle motion in IsaMills [texte imprimé] / C.T. Jayasundara, Auteur ; R.Y. Yang, Auteur ; B.Y. Guo, Auteur . - 2009 . - pp. 886–892. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 11 (Octobre 2009) . - pp. 886–892 Mots-clés : Mineral processing Discrete element method Computational fluid dynamics IsaMill™ Stirred mill Résumé : IsaMill™ is a high-speed stirred mill for a range of milling duties from ultra-fine to relatively coarse grinding in the mineral processing industry. This work investigated particle and slurry flow in a mill using a combined Discrete Element Method and Computational Fluid Dynamics (DEM-CFD) approach. Slurry properties, such as flow density and viscosity, were varied to study their effects on the flow properties in terms of flow velocity, power draw, collision frequency, collision energy and total impact energy. Significant differences were observed when slurry was introduced and other conditions unchanged. With increasing density, fluid and particle flows showed stronger circulation in the axial direction due to the larger drag forces. Increased relative velocity and interaction between particles with disc led to higher collision frequency and collision energy. Increase in flow viscosity limited particles from moving towards the outer wall and the particles were more dispersed due to the larger circulating velocity in the axial direction. The total impact energy of the media and power draw also increase with slurry density and viscosity. The developed model provides a useful framework for further analysis of particle–slurry interactions in IsaMills™. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001162

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