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MFIX2007-4 Release Announcement

Dear MFIX user,

We are pleased to announce the release of the new stable version of MFIX (MFIX2007-4). Please visit to download the latest version. Please see the attached release notes that highlight the changes from the previous version.

Please send any software related questions to or administrative questions to


MFIX Development Team

Changes from MFIX2006-4 to MFIX2007-4 (Date: 12/31/2007)

Changes in existing features:

  • Significant bug fixes were made to the DEM model implemented in MFIX (see log listing at [1]). Most of the modifications were made by Rahul Garg at Iowa State during his summer internship at NETL. Here is a brief summary of the changes:
    • Number of bug fixes and enhancements were made to handle general multiparticle mixtures with varying density as well as particle size
    • The code has tested 2D and 3D capability
  • Added/modified some test cases and tutorial cases. The test and tutorial cases are benchmarked and the summary tables are located in respective directories.
  • Several bug fixes and please have a look at the log history for a more detailed list of changes at [2]. Some notable ones are:
    • Fixed an error in the calculation of the enthalpy transfer because of mass transfer
    • The divergence terms are called consistently when solids viscosity is a constant
    • Bug fixed for wall cells that may be tagged as fluid in cyclic cases
    • Changed old-time velocity V_s0 to current velocity U_s, V_s and W_s in calc_s_ddot_s. This will accelerate convergence.
    • Moved read_database call from check_data_01 to check_data_06
  • Updated equations document [3]
  • Updated Readme - part of the distribution and readily available from [4]

New features added:

  • The following additions were made to the DEM code [5]:
    • A new and efficient cell linked list based search algorithm has been implemented and tested in 3-D DEM simulations
    • Added an interpolation suite that can be turned on to calculate the individual drag forces on the particles based on particle locations rather than cell averages
    • Added a small tool to generate input deck for DEM cases for multiparticle mixtures in mfix/tools/DES_Particle_Generator/
  • Make file has following additions
    • Option to compile using g95 under Cygwin
    • Modified the selection table under 32 bit compilers, instead of multiple questions for versions of Intel compiler etc., everything is under single list similar to 64 bit compiler options
    • Have an option to link dgtsv if machine optimized libraries are available
    • The make_file has additional options for CRAY XT3/XT4 systems
  • Modifications to make an optimized scalable version of MFIX for large parallel machines
    • The residual calculations are collected into 4 calls for every iteration
    • The dot-products in BiCGStab are reduced by almost 50%
    • Additional preconditioning (alternating sweep directions) and solver options (CG, SOR) have been added
    • Additional tools to collect statistics about scalability and load-balance


  3. S. Benyahia, M. Syamlal, T.J. O’Brien, “Summary of MFIX Equations 2005-4”, From URL, July 2007.
  5. The MFIX-DEM document is currently being updated and the DEM mailing list will be informed as soon as the document is available.