The Experts below are selected from a list of 31506 Experts worldwide ranked by ideXlab platform
Thanh D B Nguyen - One of the best experts on this subject based on the ideXlab platform.
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cfd simulation with experiments in a dual circulating fluidized bed gasifier
Computers & Chemical Engineering, 2012Co-Authors: Myung Won Seo, Byung Ho Song, Thanh D B Nguyen, Youngil Lim, Sang Done KimAbstract:Abstract Gas and particles hydrodynamic behaviors were investigated in a pilot-scale cold-mode riser and a bubbling fluidized bed gasifier by means of experiment and computational fluid dynamics (CFD). Six different experimental sets were conducted in the cold-rig dual fluidized bed (DFB) at different gas velocities in both the riser and the recycle chamber aeration. A two-dimensional (2D) multi-fluid Eulerian Model incorporating the kinetic theory of granular flows was applied to identify unsteady-state behaviors of the fluidized bed. The CFD Model predicts well the solid circulation rate in the cold-rig DFB for all the six experimental runs. A discrepancy between experiment and simulation is observed in the axial solid holdup along the riser. The simulation results demonstrate that the cold-bed simulation can be used to predict the solid circulation rate for the hot-bed operation of the DFB gasifier.
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solid circulation and loop seal characteristics of a dual circulating fluidized bed experiments and cfd simulation
Chemical Engineering Journal, 2011Co-Authors: Myung Won Seo, Sang Done Kim, Byung Ho Song, Thanh D B Nguyen, Youngil Lim, Sunwon Park, Yong Jeon KimAbstract:Abstract A dual circulating fluidized bed reactor (riser: 0.04 m × 0.11 m × 4.5 m high; bubbling fluidized bed: 0.285 m × 0.11 m × 2.13 m high) was designed and constructed to investigate hydrodynamics on dual fluidized bed gasifier (DFBG) and chemical looping combustion (CLC). Effects of gas velocities to a riser, bubbling fluidized bed, supply chamber, and recycle chamber as well as vertical aeration rate on solid circulation rate and solids flow characteristics in a loop-seal were determined experimentally. Hydrodynamic characteristics were identified by computational fluid dynamics (CFD) simulation where a two-dimensional (2D) multiphase Eulerian Model incorporating with the kinetic theory of solid particles was used. The solid circulation rate increases with increasing gas velocity into the loop-seal and the riser. At the same vertical aeration rate, the maximum solid circulation rate was obtained at a loop-seal height/base line (h/l) ratio of 2.5. When the supply chamber was connected to a bubbling fluidized bed, the pressure drop of the loop-seal was found to be affected by fluidizing state of the bubbling fluidized bed.
Sang Done Kim - One of the best experts on this subject based on the ideXlab platform.
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cfd simulation with experiments in a dual circulating fluidized bed gasifier
Computers & Chemical Engineering, 2012Co-Authors: Myung Won Seo, Byung Ho Song, Thanh D B Nguyen, Youngil Lim, Sang Done KimAbstract:Abstract Gas and particles hydrodynamic behaviors were investigated in a pilot-scale cold-mode riser and a bubbling fluidized bed gasifier by means of experiment and computational fluid dynamics (CFD). Six different experimental sets were conducted in the cold-rig dual fluidized bed (DFB) at different gas velocities in both the riser and the recycle chamber aeration. A two-dimensional (2D) multi-fluid Eulerian Model incorporating the kinetic theory of granular flows was applied to identify unsteady-state behaviors of the fluidized bed. The CFD Model predicts well the solid circulation rate in the cold-rig DFB for all the six experimental runs. A discrepancy between experiment and simulation is observed in the axial solid holdup along the riser. The simulation results demonstrate that the cold-bed simulation can be used to predict the solid circulation rate for the hot-bed operation of the DFB gasifier.
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solid circulation and loop seal characteristics of a dual circulating fluidized bed experiments and cfd simulation
Chemical Engineering Journal, 2011Co-Authors: Myung Won Seo, Sang Done Kim, Byung Ho Song, Thanh D B Nguyen, Youngil Lim, Sunwon Park, Yong Jeon KimAbstract:Abstract A dual circulating fluidized bed reactor (riser: 0.04 m × 0.11 m × 4.5 m high; bubbling fluidized bed: 0.285 m × 0.11 m × 2.13 m high) was designed and constructed to investigate hydrodynamics on dual fluidized bed gasifier (DFBG) and chemical looping combustion (CLC). Effects of gas velocities to a riser, bubbling fluidized bed, supply chamber, and recycle chamber as well as vertical aeration rate on solid circulation rate and solids flow characteristics in a loop-seal were determined experimentally. Hydrodynamic characteristics were identified by computational fluid dynamics (CFD) simulation where a two-dimensional (2D) multiphase Eulerian Model incorporating with the kinetic theory of solid particles was used. The solid circulation rate increases with increasing gas velocity into the loop-seal and the riser. At the same vertical aeration rate, the maximum solid circulation rate was obtained at a loop-seal height/base line (h/l) ratio of 2.5. When the supply chamber was connected to a bubbling fluidized bed, the pressure drop of the loop-seal was found to be affected by fluidizing state of the bubbling fluidized bed.
Junwu Wang - One of the best experts on this subject based on the ideXlab platform.
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comparative cfd analysis of heterogeneous gas solid flow in a countercurrent downer reactor
Industrial & Engineering Chemistry Research, 2014Co-Authors: Zhan Shu, Guo Peng, Junwu Wang, Nan Zhang, Weigang LinAbstract:It has been widely recognized that input parameters affected the results of Eulerian simulation of gas-solid flow. In this study, a comparative study was performed to study the effect of input parameters on the hydrodynamics of gas-solid flow in a countercurrent downer reactor. It was concluded that the input parameters of the Eulerian Model, including restitution coefficients, specularity coefficient, and drag correlation, have a major effect on the bed hydrodynamics, in accordance with previous studies on other types of gas-fluidized beds. More importantly, we show that it is possible to match the experimental data either by changing the wall boundary conditions or by correcting the interphase drag force. Therefore, there is no unique way to tune the input parameters to fit the experimental data. This study indicated that researchers have to pay great caution when selecting input parameters and highlighted the requirement of stringent experimental tests of the state-of-the-art Eulerian Models.
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Eulerian simulation of gas solid flow in a countercurrent downer
Chemical Engineering Journal, 2013Co-Authors: Guo Peng, Pengfei Dong, Junwu Wang, Weigang LinAbstract:Countercurrent gas-solid downer reactor has been used in various processes, however, fundamental studies on the hydrodynamics of such reactors are sparse, especially, there is no computational fluid dynamics study available. To this end, an empirical inter-phase drag correlation, based on experimental data available in literature, is proposed to address the key role of meso-scale particle clustering structure in determining effective inter-phase drag force. The proposed drag correlation is then integrated into Eulerian Model to study the hydrodynamics of gas-solid flow in a countercurrent downer reactor. It was shown that the measured axial pressure distribution and radial solid concentration profiles can be reproduced reasonably well and the radial particle velocity profile can be qualitatively captured as well. Present study offers a preliminary validation of feasibility of Modeling gas-solid in a countercurrent downer using Eulerian Model. (C) 2013 Elsevier B.V. All rights reserved.
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a review of Eulerian simulation of geldart a particles in gas fluidized beds
Industrial & Engineering Chemistry Research, 2009Co-Authors: Junwu WangAbstract:Although great progress has been made in Modeling the gas fluidization of Geldart B and D particles and dilute gas−solid flow by standard Eulerian approach, researchers have shown that, because of the limitation of computational resources and the formation of subgrid-scale (SGS) heterogeneous structures, Eulerian Model with a suitable SGS Model for constitutive law is necessary to simulate the hydrodynamics of large-scale gas-fluidized beds containing Geldart A particles. In this article, a state-of-the-art review of Eulerian Modeling of Geldart A particles in gas-fluidized beds is presented. The available methods for establishing SGS Models are classified into six categories, that is, empirical correlation method, scaling factor method, structure-based method, modified Syamlal and O’Brien drag correlation method, EMMS-Model-based method, and correlative multiscale method. The basic ideas of those methods, as well as their advant
Weigang Lin - One of the best experts on this subject based on the ideXlab platform.
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comparative cfd analysis of heterogeneous gas solid flow in a countercurrent downer reactor
Industrial & Engineering Chemistry Research, 2014Co-Authors: Zhan Shu, Guo Peng, Junwu Wang, Nan Zhang, Weigang LinAbstract:It has been widely recognized that input parameters affected the results of Eulerian simulation of gas-solid flow. In this study, a comparative study was performed to study the effect of input parameters on the hydrodynamics of gas-solid flow in a countercurrent downer reactor. It was concluded that the input parameters of the Eulerian Model, including restitution coefficients, specularity coefficient, and drag correlation, have a major effect on the bed hydrodynamics, in accordance with previous studies on other types of gas-fluidized beds. More importantly, we show that it is possible to match the experimental data either by changing the wall boundary conditions or by correcting the interphase drag force. Therefore, there is no unique way to tune the input parameters to fit the experimental data. This study indicated that researchers have to pay great caution when selecting input parameters and highlighted the requirement of stringent experimental tests of the state-of-the-art Eulerian Models.
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Eulerian simulation of gas solid flow in a countercurrent downer
Chemical Engineering Journal, 2013Co-Authors: Guo Peng, Pengfei Dong, Junwu Wang, Weigang LinAbstract:Countercurrent gas-solid downer reactor has been used in various processes, however, fundamental studies on the hydrodynamics of such reactors are sparse, especially, there is no computational fluid dynamics study available. To this end, an empirical inter-phase drag correlation, based on experimental data available in literature, is proposed to address the key role of meso-scale particle clustering structure in determining effective inter-phase drag force. The proposed drag correlation is then integrated into Eulerian Model to study the hydrodynamics of gas-solid flow in a countercurrent downer reactor. It was shown that the measured axial pressure distribution and radial solid concentration profiles can be reproduced reasonably well and the radial particle velocity profile can be qualitatively captured as well. Present study offers a preliminary validation of feasibility of Modeling gas-solid in a countercurrent downer using Eulerian Model. (C) 2013 Elsevier B.V. All rights reserved.
Myung Won Seo - One of the best experts on this subject based on the ideXlab platform.
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cfd simulation with experiments in a dual circulating fluidized bed gasifier
Computers & Chemical Engineering, 2012Co-Authors: Myung Won Seo, Byung Ho Song, Thanh D B Nguyen, Youngil Lim, Sang Done KimAbstract:Abstract Gas and particles hydrodynamic behaviors were investigated in a pilot-scale cold-mode riser and a bubbling fluidized bed gasifier by means of experiment and computational fluid dynamics (CFD). Six different experimental sets were conducted in the cold-rig dual fluidized bed (DFB) at different gas velocities in both the riser and the recycle chamber aeration. A two-dimensional (2D) multi-fluid Eulerian Model incorporating the kinetic theory of granular flows was applied to identify unsteady-state behaviors of the fluidized bed. The CFD Model predicts well the solid circulation rate in the cold-rig DFB for all the six experimental runs. A discrepancy between experiment and simulation is observed in the axial solid holdup along the riser. The simulation results demonstrate that the cold-bed simulation can be used to predict the solid circulation rate for the hot-bed operation of the DFB gasifier.
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solid circulation and loop seal characteristics of a dual circulating fluidized bed experiments and cfd simulation
Chemical Engineering Journal, 2011Co-Authors: Myung Won Seo, Sang Done Kim, Byung Ho Song, Thanh D B Nguyen, Youngil Lim, Sunwon Park, Yong Jeon KimAbstract:Abstract A dual circulating fluidized bed reactor (riser: 0.04 m × 0.11 m × 4.5 m high; bubbling fluidized bed: 0.285 m × 0.11 m × 2.13 m high) was designed and constructed to investigate hydrodynamics on dual fluidized bed gasifier (DFBG) and chemical looping combustion (CLC). Effects of gas velocities to a riser, bubbling fluidized bed, supply chamber, and recycle chamber as well as vertical aeration rate on solid circulation rate and solids flow characteristics in a loop-seal were determined experimentally. Hydrodynamic characteristics were identified by computational fluid dynamics (CFD) simulation where a two-dimensional (2D) multiphase Eulerian Model incorporating with the kinetic theory of solid particles was used. The solid circulation rate increases with increasing gas velocity into the loop-seal and the riser. At the same vertical aeration rate, the maximum solid circulation rate was obtained at a loop-seal height/base line (h/l) ratio of 2.5. When the supply chamber was connected to a bubbling fluidized bed, the pressure drop of the loop-seal was found to be affected by fluidizing state of the bubbling fluidized bed.
