A study of bubbling and slugging fluidised beds using the two-fluid granular temperature model

Abstract This paper reports finite element numerical simulations of gas–solid fluidised beds using the two-fluid granular temperature model. The aim of the study has been to investigate the various phenomena that have been observed in fluidised beds but have not been subject to numerical investigation. Two fluidised beds, operating in the slugging and bubbling regimes, were modelled, and the formation, elongation, coalescence and eruption of bubbles described. The effect of an obstruction on the fluidisation efficiency in a fluidised bed was investigated. Granular temperature distribution inside the fluidised bed provided an indication of the regions on the obstruction, which could be susceptible to erosion by particle impact.

[1]  D. Geldart,et al.  Gas fluidization technology , 1986 .

[2]  K. E. Starling,et al.  Equation of State for Nonattracting Rigid Spheres , 1969 .

[3]  Dimitri Gidaspow,et al.  Validation of computed solids hydrodynamics and pressure oscillations in a bubbling atmospheric fluidized bed , 1993 .

[4]  J. Kuipers,et al.  Numerical calculation of wall‐to‐bed heat‐transfer coefficients in gas‐fluidized beds , 1992 .

[5]  Y. Tsuji,et al.  Discrete particle simulation of two-dimensional fluidized bed , 1993 .

[6]  J. Werther.  D. Geldart (Ed.): Gas Fluidization Technology, John Wiley & Sons. Chichester, New York, Brisbane, Toronto, Singapore 1986. 468 Seiten, Preis: £ 42.50 , 1987 .

[7]  Bjørn H. Hjertager,et al.  An experimental and numerical study of flow patterns in a circulating fluidized bed reactor , 1996 .

[8]  Mridul Gautam,et al.  Computer simulation of bubbles in large-particle fluidized beds , 1998 .

[9]  Howard H. Hu.  Direct simulation of flows of solid-liquid mixtures , 1996 .

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

[11]  B. T. Chao,et al.  A novel radioactive particle tracking facility for measurement of solids motion in gas fluidized beds , 1985 .

[12]  A. Wolf,et al.  Determining Lyapunov exponents from a time series , 1985 .

[13]  J. E. Ungar,et al.  Boundary conditions for high-shear grain flows , 1984, Journal of Fluid Mechanics.

[14]  H. Enwald,et al.  Eulerian two-phase flow theory applied to fluidization , 1996 .

[15]  J. Grace,et al.  Hydrodynamics of gas-solid fluidization , 1995 .

[16]  S. L. Soo,et al.  Fluid dynamics of multiphase systems , 1967 .

[17]  J. X. Bouillard,et al.  Porosity distributions in a fluidized bed with an immersed obstacle , 1989 .

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

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

[20]  J. Wilder,et al.  NUMERICAL SOLUTION OF A TWO-DIMENSIONAL FLUIDIZED BED MODEL , 1998 .

[21]  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.

[22]  H. Schlichting.  Boundary Layer Theory , 1955 .

[23]  A. P. Baskakov,et al.  A study of pressure fluctuations in a bubbling fluidized bed , 1986 .

[24]  Goodarz Ahmadi,et al.  GAS-PARTICLE TWO-PHASE TURBULENT FLOW IN A VERTICAL DUCT , 1995 .

[25]  J. Kuipers,et al.  A numerical model of gas-fluidized beds , 1992 .

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

[27]  P. Harris,et al.  A NUMERICAL METHOD FOR MODELLING THE MOTION OF A SPHERICAL BUBBLE , 1996 .

[28]  J. Jenkins.  Boundary Conditions for Rapid Granular Flow: Flat, Frictional Walls , 1992 .

[29]  Dimitri Gidaspow,et al.  Computation of circulating fluidized-bed riser flow for the Fluidization VIII benchmark test , 1999 .

[30]  D. Geldart,et al.  Large particle fluidisation , 1974 .

[31]  R. Matsuno,et al.  The Coalescence of Bubbles in a Gas-solid Fluidized Bed , 1967 .

[32]  S. Savage.  Granular Flows at High Shear Rates , 1983 .

[33]  Dimitri Gidaspow,et al.  Fluidization in Two-Dimensional Beds with a Jet. 2. Hydrodynamic Modeling , 1983 .

[34]  C.R.E. de Oliveira,et al.  Numerical modelling of gas–solid fluidized beds using the two‐fluid approach , 2001 .

[35]  Bo G Leckner,et al.  Simulation of the fluid dynamics of a bubbling fluidized bed. Experimental validation of the two-fluid model and evaluation of a parallel multiblock solver , 1999 .

[36]  T. G. Cowling,et al.  The mathematical theory of non-uniform gases , 1939 .

[37]  Claes Johnson.  Numerical solution of partial differential equations by the finite element method , 1988 .

[38]  Ronald A. Roy,et al.  The velocity of sound in fluidised beds , 1990 .

[39]  J. Grace,et al.  The influence of bubble shape on the rising velocities of large bubbles , 1967 .

[40]  Roland Clift,et al.  CONTINUOUS BUBBLING AND SLUGGING. , 1985 .

[41]  Goodarz Ahmadi,et al.  An equation of state for dense rigid sphere gases , 1986 .