MFIX documentation numerical technique

MFIX (Multiphase Flow with Interphase eXchanges) is a general-purpose hydrodynamic model for describing chemical reactions and heat transfer in dense or dilute fluid-solids flows, which typically occur in energy conversion and chemical processing reactors. The calculations give time-dependent information on pressure, temperature, composition, and velocity distributions in the reactors. The theoretical basis of the calculations is described in the MFIX Theory Guide. Installation of the code, setting up of a run, and post-processing of results are described in MFIX User`s manual. Work was started in April 1996 to increase the execution speed and accuracy of the code, which has resulted in MFIX 2.0. To improve the speed of the code the old algorithm was replaced by a more implicit algorithm. In different test cases conducted the new version runs 3 to 30 times faster than the old version. To increase the accuracy of the computations, second order accurate discretization schemes were included in MFIX 2.0. Bubbling fluidized bed simulations conducted with a second order scheme show that the predicted bubble shape is rounded, unlike the (unphysical) pointed shape predicted by the first order upwind scheme. This report describes the numerical technique used in MFIX 2.0.

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

[2]  M. Syamlal,et al.  Simulation of granular layer inversion in liquid fluidized beds , 1988 .

[3]  Torrey,et al.  K-FIX: a computer program for transient, two-dimensional, two-fluid flow. THREED: an extension of the K-FIX code for three-dimensional calculations. [BWR; PWR] , 1976 .

[4]  B. P. Leonard,et al.  Beyond first‐order upwinding: The ultra‐sharp alternative for non‐oscillatory steady‐state simulation of convection , 1990 .

[5]  S. Patankar.  Numerical Heat Transfer and Fluid Flow , 2018, Lecture Notes in Mechanical Engineering.

[6]  H. Kapitza,et al.  A 3-d poisson solver based on conjugate gradients compared to standard iterative methods and its performance on vector computers , 1987 .

[7]  B. P. Leonard,et al.  A stable and accurate convective modelling procedure based on quadratic upstream interpolation , 1990 .

[8]  M. Syamlal,et al.  MFIX documentation: User`s manual , 1994 .

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

[10]  P. Gaskell,et al.  Curvature‐compensated convective transport: SMART, A new boundedness‐ preserving transport algorithm , 1988 .

[11]  D. Brian Spalding,et al.  Numerical computation of multi-phase fluid flow and heat transfer , 1980 .

[12]  M. Syamlal.  Higher order discretization methods for the numerical simulation of fluidized beds , 1997 .

[13]  A. A. Amsden,et al.  Numerical calculation of multiphase fluid flow , 1975 .

[14]  M. Syamlal,et al.  MFIX documentation theory guide , 1993 .