Numerical simulation of flow behavior of particles and clusters in riser using two granular temperatures

Abstract Cluster in CFB riser significantly affects performance of circulating fluidized beds. To model hydrodynamic behavior in CFB risers, three phase flows were assumed in the riser, the gas phase, the dispersed particle phase, and the clusters phase. The gas–solid multi-fluid model is extended to give the macroscopic averaged equations with constitutive equations for both particle phases from kinetic theory of granular flow. The clusters and the dispersed particles have their own fluctuating energy or two individual granular temperatures. Interactions between the cluster and its surrounding dispersed particles were obtained from kinetic theory of granular flow. Drag force for gas to dispersed particles and the clusters are empirically determined. The momentum exchange between dispersed particles and clusters is modeled using the concept of molecular dynamics. Cluster properties are predicted with the cluster-based approach. The distributions of volume fractions and velocities of gas, dispersed particles and clusters are predicted. Computed solid mass fluxes and volume fractions agree with Manyele et al. [S.V. Manyele, J.H. Parssinen, J.X. Zhu, Characterizing particle aggregates in a high-density and high-flux CFB riser, Chemical Engineering Journal, 88 (2002) 151–161.] and Knowlton [T.M. Knowlton, Modelling benchmark exercise. Workshop at the Eighth Engineering Foundation Conference on Fluidization, Tours, France, 1995.] experimental data.

[1]  Ronald W. Breault,et al.  Cluster particle number and granular temperature for cork particles at the wall in the riser of a CFB , 2005 .

[2]  Liang-Shih Fan,et al.  Characteristics of choking behavior in circulating fluidized beds for Group B particles , 2004 .

[3]  D. Gidaspow,et al.  A bubbling fluidization model using kinetic theory of granular flow , 1990 .

[4]  Ronald W. Breault,et al.  Wavelet analysis to characterize cluster dynamics in a circulating fluidized bed , 2007 .

[5]  John M. Matsen,et al.  Mechanisms of choking and entrainment , 1982 .

[6]  Harles S. Campbell.  Self-diffusion in granular shear flows , 1997, Journal of Fluid Mechanics.

[7]  Wen-Ching Yang,et al.  Criteria for choking in vertical pneumatic conveying lines , 1983 .

[8]  Wen-Ching Yang,et al.  A mathematical definition of choking phenomenon and a mathematical model for predicting choking velocity and choking voidage , 1975 .

[9]  Tron Solberg,et al.  Predictions of gas/particle flow with an Eulerian model including a realistic particle size distribution , 2000 .

[10]  Jesse Zhu,et al.  Characterizing particle aggregates in a high-density and high-flux CFB riser , 2002 .

[11]  L. S. Leung,et al.  Correlation for Predicting Choking Flowrates in Vertical Pneumatic Coveying , 1971 .

[12]  Fei Wei,et al.  Lateral solids mixing behavior of different particles in a riser with FCC particles as fluidized material , 2002 .

[13]  P. Basu,et al.  A model for heat transfer in circulating fluidized beds , 1986 .

[14]  S. Sundaresan,et al.  The role of meso-scale structures in rapid gas–solid flows , 2001, Journal of Fluid Mechanics.

[15]  Rex B. Thorpe,et al.  The prediction of particle cluster properties in the near wall region of a vertical riser (200157) , 2002 .

[16]  Sankaran Sundaresan,et al.  Modeling the hydrodynamics of multiphase flow reactors: Current status and challenges , 2000 .

[17]  Jinghai Li,et al.  Analytical solution of the energy-minimization multi-scale model for gas-solid two-phase flow , 1998 .

[18]  Jean François Large,et al.  Fluidization VIII : proceedings of the Eighth Engineering Foundation Conference on Fluidization, May 14-19, 1995, Tours, France , 1996 .

[19]  H. Arastoopour,et al.  Simulation of particles and gas flow behavior in the riser section of a circulating fluidized bed using the kinetic theory approach for the particulate phase , 2000 .

[20]  F. Johnsson,et al.  Characteristics of gas mixing in a circulating fluidised bed , 2002 .

[21]  Hsiaotao Bi,et al.  Types of choking in vertical pneumatic systems , 1993 .

[22]  D. Gidaspow.  Multiphase Flow and Fluidization: Continuum and Kinetic Theory Descriptions , 1994 .

[23]  Jam Hans Kuipers,et al.  Hydrodynamic modelling of dense gas-fluidised beds: Comparison of the kinetic theory of granular flow with 3D hard-sphere discrete particle simulations , 2002 .

[24]  Kunio Kato,et al.  Hydrodynamic equivalent diameter for clusters in heterogeneous gas–solid flow , 1999 .

[25]  D. Jeffrey,et al.  Kinetic theories for granular flow: inelastic particles in Couette flow and slightly inelastic particles in a general flowfield , 1984, Journal of Fluid Mechanics.

[26]  D. Geldart,et al.  Flow regimes in vertical gas-solid contact systems , 1976 .

[27]  Kemal Tuzla,et al.  Parametric effects of particle size and gas velocity on cluster characteristics in fast fluidized beds , 2000 .

[28]  Hamid Arastoopour,et al.  Numerical simulation and experimental analysis of gas/solid flow systems: 1999 Fluor-Daniel Plenary lecture , 2001 .

[29]  Dimitri Gidaspow,et al.  Hydrodynamic simulation of gas-solid flow in a riser using kinetic theory of granular flow , 2003 .

[30]  Andrew N. Norris,et al.  Particle granular temperature in gas fluidized beds , 1996 .

[31]  D. Gidaspow,et al.  Hydrodynamics of binary fluidization in a riser : CFD simulation using two granular temperatures , 2003 .

[32]  J. Jenkins,et al.  A theory for the rapid flow of identical, smooth, nearly elastic, spherical particles , 1983, Journal of Fluid Mechanics.

[33]  Xinhua Ma,et al.  Cluster structure in a circulating fluidized bed , 1994 .

[34]  D. Gidaspow,et al.  Kinetic theory of fluidized binary granular mixtures. , 2001, Physical review. E, Statistical, nonlinear, and soft matter physics.

[35]  Filip Johnsson,et al.  Gas mixing in circulating fluidised-bed risers , 2000 .

[36]  He Yurong,et al.  Hydrodynamics of gas-solid flow around immersed tubes in bubbling fluidized beds , 2004 .

[37]  Hsiaotao Bi,et al.  Flow regime diagrams for gas-solid fluidization and upward transport , 1995 .

[38]  He Yurong,et al.  Numerical study of particle cluster flow in risers with cluster-based approach , 2005 .

[39]  A. Neri,et al.  Riser hydrodynamics: Simulation using kinetic theory , 2000 .

[40]  Jamal Chaouki,et al.  Flow structure of the solids in gas–solid fluidized beds , 2004 .

[42]  R. Jackson,et al.  Frictional–collisional constitutive relations for granular materials, with application to plane shearing , 1987, Journal of Fluid Mechanics.

[43]  Masayuki Horio,et al.  SOLID DISTRIBUTION AND MOVEMENT IN CIRCULATING FLUIDIZED BEDS , 1988 .

[44]  R. Jackson,et al.  Gas‐particle flow in a vertical pipe with particle‐particle interactions , 1989 .

[45]  M. H. Morgan,et al.  A new choking velocity correlation for vertical pneumatic conveying , 1990 .

[46]  Ronald W. Breault,et al.  A review of gas–solid dispersion and mass transfer coefficient correlations in circulating fluidized beds , 2006 .

[47]  Masayuki Horio,et al.  THREE-DIMENSIONAL FLOW VISUALIZATION OF DILUTELY DISPERSED SOLIDS IN BUBBLING AND CIRCULATING FLUIDIZED BEDS , 1994 .