Documents disponibles écrits par cet auteur

CFD–DEM study of the effect of particle density distribution on the multiphase flow and performance of dense medium cyclone / K. W. Chu in Minerals engineering, Vol. 22 N° 11 (Octobre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 11 (Octobre 2009) . - pp. 893–909 Titre : CFD–DEM study of the effect of particle density distribution on the multiphase flow and performance of dense medium cyclone Type de document : texte imprimé Auteurs : K. W. Chu, Auteur ; B. Wang, Auteur ; A. B. Yu, Auteur Année de publication : 2009 Article en page(s) : pp. 893–909 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Dense  medium  cyclone  Discrete  element  method  Computational  fluid  dynamics  Coal  preparation Résumé : A mathematical model is developed to study the coal-medium flow in a dense medium cyclone (DMC) of 1000 mm body diameter. In the model, the motion of coal particles is obtained using the Discrete Element Method (DEM) facilitated with the concept of “parcel–particle” while the flow of medium as a liquid-magnetite mixture Computational Fluid Dynamics (CFD) based on the local averaged Navier–Stokes equations. In addition the Reynolds Stress Model (RSM) is adopted to describe the anisotropic turbulence, the Volume of Fluid (VOF) model is used to describe the air-core position and multiphase mixture model used to estimate the flow of fine magnetite particles. The simulated medium and coal flows allow estimates to be made of pressure drop, efflux stream medium densities and partition curves for coal particles of different sizes and densities. These estimates are compared favourably with industrial scale measurements of a 1000 mm DMC operating under similar conditions. On this base, the effect of particle density distribution that represents the major difference between two major coal type, i.e., coking coal and thermal coal, is studied. The results are analysed in terms of medium flow pattern, particle flow pattern, partition performance and particle–fluid, particle–wall and particle–particle interaction forces. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001150 [article] CFD–DEM study of the effect of particle density distribution on the multiphase flow and performance of dense medium cyclone [texte imprimé] / K. W. Chu, Auteur ; B. Wang, Auteur ; A. B. Yu, Auteur . - 2009 . - pp. 893–909. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 11 (Octobre 2009) . - pp. 893–909 Mots-clés : Dense  medium  cyclone  Discrete  element  method  Computational  fluid  dynamics  Coal  preparation Résumé : A mathematical model is developed to study the coal-medium flow in a dense medium cyclone (DMC) of 1000 mm body diameter. In the model, the motion of coal particles is obtained using the Discrete Element Method (DEM) facilitated with the concept of “parcel–particle” while the flow of medium as a liquid-magnetite mixture Computational Fluid Dynamics (CFD) based on the local averaged Navier–Stokes equations. In addition the Reynolds Stress Model (RSM) is adopted to describe the anisotropic turbulence, the Volume of Fluid (VOF) model is used to describe the air-core position and multiphase mixture model used to estimate the flow of fine magnetite particles. The simulated medium and coal flows allow estimates to be made of pressure drop, efflux stream medium densities and partition curves for coal particles of different sizes and densities. These estimates are compared favourably with industrial scale measurements of a 1000 mm DMC operating under similar conditions. On this base, the effect of particle density distribution that represents the major difference between two major coal type, i.e., coking coal and thermal coal, is studied. The results are analysed in terms of medium flow pattern, particle flow pattern, partition performance and particle–fluid, particle–wall and particle–particle interaction forces. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001150

Computational study of flow regimes in vertical pneumatic conveying / S. B. Kuang in Industrial & engineering chemistry research, Vol. 48 N° 14 (Juillet 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6846–6858 Titre : Computational study of flow regimes in vertical pneumatic conveying Type de document : texte imprimé Auteurs : S. B. Kuang, Auteur ; A. B. Yu, Auteur ; Z. S. Zou, Auteur Année de publication : 2009 Article en page(s) : pp. 6846–6858 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Pneumatic  conveying  Flow  regimes  Three-dimensional  numerical  study Résumé : Pneumatic conveying is an important technology in industries to transport bulk materials from one location to another. Different flow regimes have been observed in such a transportation process depending on operational conditions, but the underlying fundamentals are not clear. This paper presents a three-dimensional numerical study of vertical pneumatic conveying by a combined approach of discrete element model for particles and computational fluid dynamics for gas. The approach is verified by comparing the calculated and measured results in terms of particle flow pattern and gas pressure drop. It is shown that flow regimes usually encountered in vertical pneumatic conveying and their corresponding phase diagram can be reproduced. Then forces governing the behavior of particles, such as the particle−particle, particle−fluid, and particle−wall forces, are analyzed in detail. It is shown that the roles of these forces vary with flow regimes. A new phase diagram is proposed in terms of the key forces, which can successfully identify dilute-phase flow and dense-phase flow in vertical pneumatic conveying. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900230s [article] Computational study of flow regimes in vertical pneumatic conveying [texte imprimé] / S. B. Kuang, Auteur ; A. B. Yu, Auteur ; Z. S. Zou, Auteur . - 2009 . - pp. 6846–6858. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6846–6858 Mots-clés : Pneumatic  conveying  Flow  regimes  Three-dimensional  numerical  study Résumé : Pneumatic conveying is an important technology in industries to transport bulk materials from one location to another. Different flow regimes have been observed in such a transportation process depending on operational conditions, but the underlying fundamentals are not clear. This paper presents a three-dimensional numerical study of vertical pneumatic conveying by a combined approach of discrete element model for particles and computational fluid dynamics for gas. The approach is verified by comparing the calculated and measured results in terms of particle flow pattern and gas pressure drop. It is shown that flow regimes usually encountered in vertical pneumatic conveying and their corresponding phase diagram can be reproduced. Then forces governing the behavior of particles, such as the particle−particle, particle−fluid, and particle−wall forces, are analyzed in detail. It is shown that the roles of these forces vary with flow regimes. A new phase diagram is proposed in terms of the key forces, which can successfully identify dilute-phase flow and dense-phase flow in vertical pneumatic conveying. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900230s

DEM simulation of particle flow on a multi-deck banana screen / K. J. Dong in Minerals engineering, Vol. 22 N° 11 (Octobre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 11 (Octobre 2009) . - pp. 910–920 Titre : DEM simulation of particle flow on a multi-deck banana screen Type de document : texte imprimé Auteurs : K. J. Dong, Auteur ; A. B. Yu, Auteur ; I. Brake, Auteur Année de publication : 2009 Article en page(s) : pp. 910–920 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Screening  Coal  preparation  Discrete  Element  Method  Process  simulation Résumé : Banana screen is an important innovation in screening process in the past decades to improve screen capacity. Although, it is increasingly employed in the mineral industry, the control and optimisation are still limited due to the lack of fundamental understandings of the process. This paper presents a numerical study of the particle flow on a banana screen at a particle scale by means of Discrete Element Method (DEM). Typical 3-deck and 5-deck banana screens are simulated. The effects of operational conditions and geometry on the screen performance are studied by a series of controlled numerical experiments. The results are analysed in terms of partition curves, distributions of percentage passing and other flow information, such as particle volume and velocities along the screen deck. They are useful to the development of a better understanding and the control of banana screening processes. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001046 [article] DEM simulation of particle flow on a multi-deck banana screen [texte imprimé] / K. J. Dong, Auteur ; A. B. Yu, Auteur ; I. Brake, Auteur . - 2009 . - pp. 910–920. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 11 (Octobre 2009) . - pp. 910–920 Mots-clés : Screening  Coal  preparation  Discrete  Element  Method  Process  simulation Résumé : Banana screen is an important innovation in screening process in the past decades to improve screen capacity. Although, it is increasingly employed in the mineral industry, the control and optimisation are still limited due to the lack of fundamental understandings of the process. This paper presents a numerical study of the particle flow on a banana screen at a particle scale by means of Discrete Element Method (DEM). Typical 3-deck and 5-deck banana screens are simulated. The effects of operational conditions and geometry on the screen performance are studied by a series of controlled numerical experiments. The results are analysed in terms of partition curves, distributions of percentage passing and other flow information, such as particle volume and velocities along the screen deck. They are useful to the development of a better understanding and the control of banana screening processes. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001046

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]  in Industrial & 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

Effect of bed thickness on the segregation behavior of particle mixtures in a gas fluidized bed / Y. Q. Feng in Industrial & engineering chemistry research, Vol. 49 N° 7 (Avril 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 7 (Avril 2010) . - pp. 3459–3468 Titre : Effect of bed thickness on the segregation behavior of particle mixtures in a gas fluidized bed Type de document : texte imprimé Auteurs : Y. Q. Feng, Auteur ; A. B. Yu, Auteur Année de publication : 2010 Article en page(s) : pp. 3459–3468 Note générale : Industrial Chemistry Langues : Anglais (eng) Mots-clés : Bed  Thickness  Particle  Mixtures  Gas  Fluidized Résumé : Discrete particle simulation has been recognized as a useful numerical technique to elucidate the fundamentals of particle−fluid flow, in particular, gas fluidization. In general, it is achieved by combining discrete element method (DEM) for solid flow with computational fluid dynamics (CFD) for continuum gas. Limited by computational capability, such studies are mainly conducted using a two-dimensional (2D) bed in which particles are treated as discs or a pseudo-three-dimensional (3D) bed where the bed thickness is the same as the particle diameter. The loss of one-dimensional motion may significantly affect the flow and related behavior. This paper presents a numerical study of the effect of the front and rear walls of a fluidized bed on the mixing and segregation behavior of particle mixtures. Particle diameters used for simulation are 1 mm for flotsam and 2 mm for jetsam, respectively. Numerical simulations are conducted for two beds of different thicknesses, fluidized at different gas velocities. One, referred to as the 2D case, shows the bed thickness is 1.1 times the thickness of the particle diameter of jetsam with the front and rear walls supporting the particles; the other, referred to as the 3D case, shows the bed thickness is 4.05 times the particle diameter of jetsam with the application of periodical boundary conditions to the front and rear walls which simulate the 3D motion of particles in the bed. Comparison conducted in terms of solid flow patterns shows that both 2D and 3D simulations can capture the key features of the mixing/segregation process, but the transient segregation occurs at different velocity ranges. Further comparison is conducted on the basis of microdynamic variables, such as mixing kinetics, interactions between particles and fluid, and between particles, and particle contact numbers. These quantitative comparisons demonstrate a significant difference between 2D and 3D simulations, which indicates the necessity of 3D simulation for engineering application. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901478a [article] Effect of bed thickness on the segregation behavior of particle mixtures in a gas fluidized bed [texte imprimé] / Y. Q. Feng, Auteur ; A. B. Yu, Auteur . - 2010 . - pp. 3459–3468. Industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 7 (Avril 2010) . - pp. 3459–3468 Mots-clés : Bed  Thickness  Particle  Mixtures  Gas  Fluidized Résumé : Discrete particle simulation has been recognized as a useful numerical technique to elucidate the fundamentals of particle−fluid flow, in particular, gas fluidization. In general, it is achieved by combining discrete element method (DEM) for solid flow with computational fluid dynamics (CFD) for continuum gas. Limited by computational capability, such studies are mainly conducted using a two-dimensional (2D) bed in which particles are treated as discs or a pseudo-three-dimensional (3D) bed where the bed thickness is the same as the particle diameter. The loss of one-dimensional motion may significantly affect the flow and related behavior. This paper presents a numerical study of the effect of the front and rear walls of a fluidized bed on the mixing and segregation behavior of particle mixtures. Particle diameters used for simulation are 1 mm for flotsam and 2 mm for jetsam, respectively. Numerical simulations are conducted for two beds of different thicknesses, fluidized at different gas velocities. One, referred to as the 2D case, shows the bed thickness is 1.1 times the thickness of the particle diameter of jetsam with the front and rear walls supporting the particles; the other, referred to as the 3D case, shows the bed thickness is 4.05 times the particle diameter of jetsam with the application of periodical boundary conditions to the front and rear walls which simulate the 3D motion of particles in the bed. Comparison conducted in terms of solid flow patterns shows that both 2D and 3D simulations can capture the key features of the mixing/segregation process, but the transient segregation occurs at different velocity ranges. Further comparison is conducted on the basis of microdynamic variables, such as mixing kinetics, interactions between particles and fluid, and between particles, and particle contact numbers. These quantitative comparisons demonstrate a significant difference between 2D and 3D simulations, which indicates the necessity of 3D simulation for engineering application. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901478a

Effect of blade speed on granular flow and mixing in a cylindrical mixer / G. R. Chandratilleke in Industrial & engineering chemistry research, Vol. 49 N° 11 (Juin 2010) 

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Effect of particle properties on particle percolation behaviour in a packed bed / H.P. Zhu in Minerals engineering, Vol. 22 N° 11 (Octobre 2009) 

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Modeling the multiphase flow in a dense medium cyclone / B. Wang in Industrial & engineering chemistry research, Vol. 48 N° 7 (Avril 2009) 

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Modelling of multiphase flow in ironmaking blast furnace / X. F. Dong in Industrial & engineering chemistry research, Vol. 48 N°1 (Janvier 2009) 

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Numerical simulation of the gas-solid flow in three-dimensional pneumatic conveying bends / K. W. Chu in Industrial & engineering chemistry research, Vol. 47 N°18 (Septembre 2008) 

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Numerical studies of the effects of medium properties in dense medium cyclone operations / B. Wang in Minerals engineering, Vol. 22 N° 11 (Octobre 2009) 

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