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Aibing Yu - One of the best experts on this subject based on the ideXlab platform.
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gas solid flow in an ironmaking blast furnace ii discrete Particle Simulation
Powder Technology, 2011Co-Authors: Zongyan Zhou, Aibing Yu, Bryan D Wright, Paul ZulliAbstract:Abstract This paper presents a numerical study of the gas–solid flow in an ironmaking blast furnace by combining discrete Particle Simulation (DPS) with computational fluid dynamics (CFD). The conditions considered include different gas and solid flow rates, asymmetric conditions such as non-uniform gas and solid flow rates in blast furnace raceways, and existence of scabs on the side walls. The obtained results show that main gas–solid flow features under different conditions can be captured by this approach. The computed results are consistent with the experimental observations. Microscopic structures including the force structure are examined to analyze the effect of gas flow on the solid flow at a Particle scale. Further, macroscopic properties such as solid pressure and porosity are obtained from the corresponding microscopic properties by an averaging method. It is shown that the solid pressure–porosity relationship in a blast furnace is complicated, varying with different flow zones. None of the literature correlations considered can fully describe such a feature. Based on the simulated results, two correlations are formulated to describe the solid pressure–porosity relationship covering different flow regimes. But their general application needs further tests in future work.
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discrete Particle Simulation of particulate systems a review of major applications and findings
Chemical Engineering Science, 2008Co-Authors: Zongyan Zhou, Runyu Yang, Aibing YuAbstract:Abstract Understanding and modelling the dynamic behaviour of particulate systems has been a major research focus worldwide for many years. Discrete Particle Simulation plays an important role in this area. This technique can provide dynamic information, such as the trajectories of and transient forces acting on individual Particles, which is difficult to obtain by the conventional experimental techniques. Consequently, it has been increasingly used by various investigators for different particulate processes. In spite of the large bulk volume, little effort has been made to comprehensively review and summarize the progress made in the past. To overcome this gap, we have recently completed a review of the major work in this area in two separate parts. The first part has been published [Zhu, H.P., Zhou, Z.Y., Yang, R.Y., Yu, A.B., 2007. Discrete Particle Simulation of particulate systems: theoretical developments. Chemical Engineering Science 62, 3378–3392.], which reviews the major theoretical developments. This paper is the second one, aiming to provide a summary of the studies based on discrete Particle Simulation in the past two decades or so. The studies are categorized into three subject areas: Particle packing, Particle flow, and Particle–fluid flow. The major findings are discussed, with emphasis on the microdynamics including packing/flow structure and Particle–Particle, Particle–fluid and Particle–wall interaction forces. It is concluded that discrete Particle Simulation is an effective method for Particle scale research of particulate matter. The needs for future research are also discussed.
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discrete Particle Simulation of particulate systems theoretical developments
Chemical Engineering Science, 2007Co-Authors: Haiping Zhu, Zongyan Zhou, Runyu Yang, Aibing YuAbstract:Abstract Particle science and technology is a rapidly developing interdisciplinary research area with its core being the understanding of the relationships between micro- and macroscopic properties of particulate/granular matter—a state of matter that is widely encountered but poorly understood. The macroscopic behaviour of particulate matter is controlled by the interactions between individual Particles as well as interactions with surrounding fluids. Understanding the microscopic mechanisms in terms of these interaction forces is therefore key to leading to truly interdisciplinary research into particulate matter and producing results that can be generally used. This aim can be effectively achieved via Particle scale research based on detailed microdynamic information such as the forces acting on and trajectories of individual Particles in a considered system. In recent years, such research has been rapidly developed worldwide, mainly as a result of the rapid development of discrete Particle Simulation technique and computer technology. This paper reviews the work in this area with special reference to the discrete element method and associated theoretical developments. It covers three important aspects: models for the calculation of the Particle–Particle and Particle–fluid interaction forces, coupling of discrete element method with computational fluid dynamics to describe Particle–fluid flow, and the theories for linking discrete to continuum modelling. Needs for future development are also discussed.
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assessment of model formulations in the discrete Particle Simulation of gas solid flow
Industrial & Engineering Chemistry Research, 2004Co-Authors: Yuqing Feng, Aibing YuAbstract:Discrete Particle Simulation has been recognized as a useful numerical technique for elucidating the fundamentals of granular matter. For gas−solid two-phase flow in fluidization, such Simulations are achieved by combining the discrete flow of the Particle phase with the continuum flow of the gas phase. However, differences exist in the actual implementation of this idea in the literature. This paper attempts to rationalize this matter by discussing important aspects including the governing equations in relation to the so-called models A and B, which use different treatments of pressure drop in the well-established two-fluid model, different coupling schemes between the gas and solid phases, and different equations for quantifying the Particle−fluid interaction. For the purpose of quantitative analysis, gas fluidization of binary mixtures of Particles is simulated with different model formulations, and a comparison of the results in terms of flow pattern and mixing/segregation kinetics shows a significant...
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discrete Particle Simulation of gas fluidization of Particle mixtures
Aiche Journal, 2004Co-Authors: Yuqing Feng, Aibing Yu, B H Xu, S J Zhang, Paul ZulliAbstract:This report presents a numerical study of segregation and mixing of binary mixtures of Particles in a gas-fluidized bed by means of discrete Particle Simulation, where the motion of individual Particles is 3-D and the flow of continuous gas is 2-D. Periodic boundary conditions are applied to the front and rear walls to represent a bed of large thickness with a relatively small number of Particles. Two initial packing conditions are used in this Simulation: completely separated, with the flotsam (1 × 10−3 m in diameter) on the top of the jetsam (2 × 10−3 m in diameter), and well mixed. The flotsam and jetsam are of the same density, with each counting 50% in weight. Gas is injected uniformly at the bottom. Two superficial gas velocities, 1.0 and 1.4 m/s, are used in the Simulation, producing significant segregation and good mixing, respectively. The results show that the degree and rate of segregation or mixing are significantly affected by gas velocity and the final equilibrium states are not affected by the initial packing states for a given gas velocity. Significant segregation occurs at a gas velocity of 1.0 m/s, with the top fluidized layer rich in flotsam and the bottom defluidized layer rich in jetsam, whereas there was less segregation at 1.4 m/s with most of the bed fluidized. The simulated results are qualitatively comparable with those observed in the physical experiments conducted under similar conditions. On this basis, the mixing kinetics obtained from the numerical Simulation is quantified with a weighted Lacey mixing index and explained in terms of microdynamic results in relation to Particle–Particle and Particle–fluid interactions. It is proposed that an appropriate sampling size should be able to describe properly the two extremes: well mixed and fully segregated. The results also demonstrate that size segregation occurs as a result of the strong fluid drag force lifting the flotsam before a dynamical equilibrium is reached, and the Particle–Particle interaction, like the Particle–fluid interaction, plays an important role in achieving uniform fluidization. © 2004 American Institute of Chemical Engineers AIChE J, 50: 1713–1728, 2004
Chongbin Zhao - One of the best experts on this subject based on the ideXlab platform.
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Particle Simulation of thermally induced rock damage with consideration of temperature dependent elastic modulus and strength
Computers and Geotechnics, 2014Co-Authors: Ming Xia, Chongbin Zhao, B E HobbsAbstract:Abstract Based on the Particle Simulation method, a thermo-mechanical coupling Particle model is proposed for simulating thermally-induced rock damage. In this model, rock material is simulated as an assembly of Particles, which are connected to each other through their bonds, in the case of simulating mechanical deformation, but connected to each other through thermal pipes in the case of simulating heat conduction. The main advantages of using this model are that: (1) microscopic parameters of this model can be directly determined from the related macroscopic ones; (2) the temperature-dependent elastic modulus and strength are considered in an explicit manner, so that thermally-induced rock damage can be realistically simulated in a thermo-mechanical coupling problem. The related Simulation results from an application example have demonstrated that: (1) the proposed model can produce similar behaviors to those observed in experiments; (2) the final failure is initiated from the outer surface of the testing sample and propagates toward the borehole; (3) microscopic crack initiation and propagation processes can be reasonably simulated at the cooling stage.
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Computational modeling of free-surface slurry flow problems using Particle Simulation method
Journal of Central South University, 2013Co-Authors: Chongbin Zhao, Shenglin Peng, Liangming Liu, Bruce E. Hobbs, Alison OrdAbstract:The Particle Simulation method is used to solve free-surface slurry flow problems that may be encountered in several scientific and engineering fields. The main idea behind the use of the Particle Simulation method is to treat granular or other materials as an assembly of many Particles. Compared with the continuum-mechanics-based numerical methods such as the finite element and finite volume methods, the movement of each Particle is accurately described in the Particle Simulation method so that the free surface of a slurry flow problem can be automatically obtained. The major advantage of using the Particle Simulation method is that only a simple numerical algorithm is needed to solve the governing equation of a Particle Simulation system. For the purpose of illustrating how to use the Particle Simulation method to solve free-surface flow problems, three examples involving slurry flow on three different types of river beds have been considered. The related Particle Simulation results obtained from these three examples have demonstrated that: 1) The Particle Simulation method is a promising and useful method for solving free-surface flow problems encountered in both the scientific and engineering fields; 2) The shape and irregular roughness of a river bed can have a significant effect on the free surface morphologies of slurry flow when it passes through the river bed.
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Particle Simulation of spontaneous crack generation associated with the laccolithic type of magma intrusion processes
International Journal for Numerical Methods in Engineering, 2008Co-Authors: Chongbin Zhao, B E Hobbs, A Ord, Shenglin PengAbstract:The main purpose of this paper is to extend the Particle Simulation method for simulating the spontaneous crack generation problem associated with the laccolithic type of magma intrusion and emplacement within the crust of the Earth. As the mechanical behavior of the intruded magma is different from that of its surrounding rocks, the intruded magma is simulated using fluid Particles of relatively less compressibility, whereas the surrounding rock of the intruded magma is simulated using conventional solid Particles. Using the proposed Particle Simulation method, it is possible to simulate some magma-intrusion-induced important phenomena, such as hydraulic fracturing associated with the creation of a magma chamber, complicated moving boundaries associated with the growing magma chamber and spontaneous crack initiation in the surrounding rocks when magma pressure is propagating from the magma chamber into the surrounding rocks. The related Particle Simulation results have demonstrated that (1) the proposed Particle Simulation method is useful and applicable for simulating spontaneous crack generation problems associated with the laccolithic type of magma intrusion process within the crust of the Earth; (2) the generated cracks are highly concentrated on the narrow region that is just above the intruded magma chamber; and (3) the layer-stiffness ratio has a significant effect on the spontaneously generated crack patterns within the upper crust of the Earth.
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An upscale theory of Particle Simulation for two‐dimensional quasi‐static problems
International Journal for Numerical Methods in Engineering, 2007Co-Authors: Chongbin Zhao, Shenglin Peng, Bruce E. Hobbs, Alison Ord, Liangming LiuAbstract:An upscale theory of the Particle Simulation, which is based on the distinct element method, is presented for two-dimensional quasi-static problems. Since the present upscale theory is comprised of four similarity criteria between different length-scale Particle-Simulation models, it reveals the intrinsic relationship between the Particle-Simulation solution obtained from a small length-scale (e.g. a laboratory length-scale) model and that obtained from a large length-scale (e.g. a geological length-scale) one. The present upscale theory is of significant theoretical value in the Particle Simulation of two-dimensional systems, at least from the following two points of view. (1) If the mechanical response of a Particle model of a small length-scale is used to indirectly investigate that of a large length-scale, then the present upscale theory provides the necessary conditions, under which the Particle model of the small length-scale needs to be satisfied so that a similarity between the mechanical responses of two different length-scale Particle models can be maintained. (2) If a Particle model of a large length-scale is used to directly investigate the mechanical response of the model, then the present upscale theory can be used to determine the necessary Particle-scale mechanical properties from the macroscopic mechanical properties that are obtained from either a laboratory test or an in situ measurement. The related Simulation results from two typical examples of significantly different length-scales (i.e. a metre-scale and a kilometre-scale) have demonstrated the usefulness and correctness of the proposed upscale theory for simulating different length-scale problems in quasi-static geological systems.
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Numerical modelling of spontaneous crack generation in brittle materials using the Particle Simulation method
Engineering Computations, 2006Co-Authors: Chongbin Zhao, Tatsuro Nishiyama, Akira MurakamiAbstract:Purpose – The main purpose of this paper is to present and use the Particle Simulation method to explicitly simulate the spontaneous crack initiation phenomenon in brittle materials, and to compare the Particle Simulation results with experimental ones on the laboratory scale.Design/methodology/approach – Using the Particle Simulation method, the brittle material is simulated as an assembly of Particles so that the microscopic mechanism of inter‐ and intra‐Particle crack initiation can be straightforwardly considered on the microscopic scale. A laboratory test has been conducted using a gypsum sample model to validate the Particle Simulation method for explicitly simulating the spontaneous crack initiation phenomenon.Findings – The paper finds that in terms of simulating the macroscopic sliding surface along or around the contact plane between a block and its foundation, both the laboratory test and the Particle Simulation have produced consistent results. This indicated that the Particle Simulation metho...
Zongyan Zhou - One of the best experts on this subject based on the ideXlab platform.
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gas solid flow in an ironmaking blast furnace ii discrete Particle Simulation
Powder Technology, 2011Co-Authors: Zongyan Zhou, Aibing Yu, Bryan D Wright, Paul ZulliAbstract:Abstract This paper presents a numerical study of the gas–solid flow in an ironmaking blast furnace by combining discrete Particle Simulation (DPS) with computational fluid dynamics (CFD). The conditions considered include different gas and solid flow rates, asymmetric conditions such as non-uniform gas and solid flow rates in blast furnace raceways, and existence of scabs on the side walls. The obtained results show that main gas–solid flow features under different conditions can be captured by this approach. The computed results are consistent with the experimental observations. Microscopic structures including the force structure are examined to analyze the effect of gas flow on the solid flow at a Particle scale. Further, macroscopic properties such as solid pressure and porosity are obtained from the corresponding microscopic properties by an averaging method. It is shown that the solid pressure–porosity relationship in a blast furnace is complicated, varying with different flow zones. None of the literature correlations considered can fully describe such a feature. Based on the simulated results, two correlations are formulated to describe the solid pressure–porosity relationship covering different flow regimes. But their general application needs further tests in future work.
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discrete Particle Simulation of particulate systems a review of major applications and findings
Chemical Engineering Science, 2008Co-Authors: Zongyan Zhou, Runyu Yang, Aibing YuAbstract:Abstract Understanding and modelling the dynamic behaviour of particulate systems has been a major research focus worldwide for many years. Discrete Particle Simulation plays an important role in this area. This technique can provide dynamic information, such as the trajectories of and transient forces acting on individual Particles, which is difficult to obtain by the conventional experimental techniques. Consequently, it has been increasingly used by various investigators for different particulate processes. In spite of the large bulk volume, little effort has been made to comprehensively review and summarize the progress made in the past. To overcome this gap, we have recently completed a review of the major work in this area in two separate parts. The first part has been published [Zhu, H.P., Zhou, Z.Y., Yang, R.Y., Yu, A.B., 2007. Discrete Particle Simulation of particulate systems: theoretical developments. Chemical Engineering Science 62, 3378–3392.], which reviews the major theoretical developments. This paper is the second one, aiming to provide a summary of the studies based on discrete Particle Simulation in the past two decades or so. The studies are categorized into three subject areas: Particle packing, Particle flow, and Particle–fluid flow. The major findings are discussed, with emphasis on the microdynamics including packing/flow structure and Particle–Particle, Particle–fluid and Particle–wall interaction forces. It is concluded that discrete Particle Simulation is an effective method for Particle scale research of particulate matter. The needs for future research are also discussed.
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discrete Particle Simulation of particulate systems theoretical developments
Chemical Engineering Science, 2007Co-Authors: Haiping Zhu, Zongyan Zhou, Runyu Yang, Aibing YuAbstract:Abstract Particle science and technology is a rapidly developing interdisciplinary research area with its core being the understanding of the relationships between micro- and macroscopic properties of particulate/granular matter—a state of matter that is widely encountered but poorly understood. The macroscopic behaviour of particulate matter is controlled by the interactions between individual Particles as well as interactions with surrounding fluids. Understanding the microscopic mechanisms in terms of these interaction forces is therefore key to leading to truly interdisciplinary research into particulate matter and producing results that can be generally used. This aim can be effectively achieved via Particle scale research based on detailed microdynamic information such as the forces acting on and trajectories of individual Particles in a considered system. In recent years, such research has been rapidly developed worldwide, mainly as a result of the rapid development of discrete Particle Simulation technique and computer technology. This paper reviews the work in this area with special reference to the discrete element method and associated theoretical developments. It covers three important aspects: models for the calculation of the Particle–Particle and Particle–fluid interaction forces, coupling of discrete element method with computational fluid dynamics to describe Particle–fluid flow, and the theories for linking discrete to continuum modelling. Needs for future development are also discussed.
Shenglin Peng - One of the best experts on this subject based on the ideXlab platform.
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Computational modeling of free-surface slurry flow problems using Particle Simulation method
Journal of Central South University, 2013Co-Authors: Chongbin Zhao, Shenglin Peng, Liangming Liu, Bruce E. Hobbs, Alison OrdAbstract:The Particle Simulation method is used to solve free-surface slurry flow problems that may be encountered in several scientific and engineering fields. The main idea behind the use of the Particle Simulation method is to treat granular or other materials as an assembly of many Particles. Compared with the continuum-mechanics-based numerical methods such as the finite element and finite volume methods, the movement of each Particle is accurately described in the Particle Simulation method so that the free surface of a slurry flow problem can be automatically obtained. The major advantage of using the Particle Simulation method is that only a simple numerical algorithm is needed to solve the governing equation of a Particle Simulation system. For the purpose of illustrating how to use the Particle Simulation method to solve free-surface flow problems, three examples involving slurry flow on three different types of river beds have been considered. The related Particle Simulation results obtained from these three examples have demonstrated that: 1) The Particle Simulation method is a promising and useful method for solving free-surface flow problems encountered in both the scientific and engineering fields; 2) The shape and irregular roughness of a river bed can have a significant effect on the free surface morphologies of slurry flow when it passes through the river bed.
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Particle Simulation of spontaneous crack generation associated with the laccolithic type of magma intrusion processes
International Journal for Numerical Methods in Engineering, 2008Co-Authors: Chongbin Zhao, B E Hobbs, A Ord, Shenglin PengAbstract:The main purpose of this paper is to extend the Particle Simulation method for simulating the spontaneous crack generation problem associated with the laccolithic type of magma intrusion and emplacement within the crust of the Earth. As the mechanical behavior of the intruded magma is different from that of its surrounding rocks, the intruded magma is simulated using fluid Particles of relatively less compressibility, whereas the surrounding rock of the intruded magma is simulated using conventional solid Particles. Using the proposed Particle Simulation method, it is possible to simulate some magma-intrusion-induced important phenomena, such as hydraulic fracturing associated with the creation of a magma chamber, complicated moving boundaries associated with the growing magma chamber and spontaneous crack initiation in the surrounding rocks when magma pressure is propagating from the magma chamber into the surrounding rocks. The related Particle Simulation results have demonstrated that (1) the proposed Particle Simulation method is useful and applicable for simulating spontaneous crack generation problems associated with the laccolithic type of magma intrusion process within the crust of the Earth; (2) the generated cracks are highly concentrated on the narrow region that is just above the intruded magma chamber; and (3) the layer-stiffness ratio has a significant effect on the spontaneously generated crack patterns within the upper crust of the Earth.
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An upscale theory of Particle Simulation for two‐dimensional quasi‐static problems
International Journal for Numerical Methods in Engineering, 2007Co-Authors: Chongbin Zhao, Shenglin Peng, Bruce E. Hobbs, Alison Ord, Liangming LiuAbstract:An upscale theory of the Particle Simulation, which is based on the distinct element method, is presented for two-dimensional quasi-static problems. Since the present upscale theory is comprised of four similarity criteria between different length-scale Particle-Simulation models, it reveals the intrinsic relationship between the Particle-Simulation solution obtained from a small length-scale (e.g. a laboratory length-scale) model and that obtained from a large length-scale (e.g. a geological length-scale) one. The present upscale theory is of significant theoretical value in the Particle Simulation of two-dimensional systems, at least from the following two points of view. (1) If the mechanical response of a Particle model of a small length-scale is used to indirectly investigate that of a large length-scale, then the present upscale theory provides the necessary conditions, under which the Particle model of the small length-scale needs to be satisfied so that a similarity between the mechanical responses of two different length-scale Particle models can be maintained. (2) If a Particle model of a large length-scale is used to directly investigate the mechanical response of the model, then the present upscale theory can be used to determine the necessary Particle-scale mechanical properties from the macroscopic mechanical properties that are obtained from either a laboratory test or an in situ measurement. The related Simulation results from two typical examples of significantly different length-scales (i.e. a metre-scale and a kilometre-scale) have demonstrated the usefulness and correctness of the proposed upscale theory for simulating different length-scale problems in quasi-static geological systems.
Paul Zulli - One of the best experts on this subject based on the ideXlab platform.
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gas solid flow in an ironmaking blast furnace ii discrete Particle Simulation
Powder Technology, 2011Co-Authors: Zongyan Zhou, Aibing Yu, Bryan D Wright, Paul ZulliAbstract:Abstract This paper presents a numerical study of the gas–solid flow in an ironmaking blast furnace by combining discrete Particle Simulation (DPS) with computational fluid dynamics (CFD). The conditions considered include different gas and solid flow rates, asymmetric conditions such as non-uniform gas and solid flow rates in blast furnace raceways, and existence of scabs on the side walls. The obtained results show that main gas–solid flow features under different conditions can be captured by this approach. The computed results are consistent with the experimental observations. Microscopic structures including the force structure are examined to analyze the effect of gas flow on the solid flow at a Particle scale. Further, macroscopic properties such as solid pressure and porosity are obtained from the corresponding microscopic properties by an averaging method. It is shown that the solid pressure–porosity relationship in a blast furnace is complicated, varying with different flow zones. None of the literature correlations considered can fully describe such a feature. Based on the simulated results, two correlations are formulated to describe the solid pressure–porosity relationship covering different flow regimes. But their general application needs further tests in future work.
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discrete Particle Simulation of gas fluidization of Particle mixtures
Aiche Journal, 2004Co-Authors: Yuqing Feng, Aibing Yu, B H Xu, S J Zhang, Paul ZulliAbstract:This report presents a numerical study of segregation and mixing of binary mixtures of Particles in a gas-fluidized bed by means of discrete Particle Simulation, where the motion of individual Particles is 3-D and the flow of continuous gas is 2-D. Periodic boundary conditions are applied to the front and rear walls to represent a bed of large thickness with a relatively small number of Particles. Two initial packing conditions are used in this Simulation: completely separated, with the flotsam (1 × 10−3 m in diameter) on the top of the jetsam (2 × 10−3 m in diameter), and well mixed. The flotsam and jetsam are of the same density, with each counting 50% in weight. Gas is injected uniformly at the bottom. Two superficial gas velocities, 1.0 and 1.4 m/s, are used in the Simulation, producing significant segregation and good mixing, respectively. The results show that the degree and rate of segregation or mixing are significantly affected by gas velocity and the final equilibrium states are not affected by the initial packing states for a given gas velocity. Significant segregation occurs at a gas velocity of 1.0 m/s, with the top fluidized layer rich in flotsam and the bottom defluidized layer rich in jetsam, whereas there was less segregation at 1.4 m/s with most of the bed fluidized. The simulated results are qualitatively comparable with those observed in the physical experiments conducted under similar conditions. On this basis, the mixing kinetics obtained from the numerical Simulation is quantified with a weighted Lacey mixing index and explained in terms of microdynamic results in relation to Particle–Particle and Particle–fluid interactions. It is proposed that an appropriate sampling size should be able to describe properly the two extremes: well mixed and fully segregated. The results also demonstrate that size segregation occurs as a result of the strong fluid drag force lifting the flotsam before a dynamical equilibrium is reached, and the Particle–Particle interaction, like the Particle–fluid interaction, plays an important role in achieving uniform fluidization. © 2004 American Institute of Chemical Engineers AIChE J, 50: 1713–1728, 2004
