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MFiX 21.4 Release Announcement

MFiX 21.4 Release

Dear MFiX user,

We are pleased to announce the MFiX 21.4 release. Please download the latest version. See the release note below that highlights the changes from the previous version.

Please visit the MFS forum for any software related questions, or send administrative questions to

The MFiX Development Team

New features:

  • Implementation of polydispersity for PIC. Normal, normal-log and custom Particle Size Distributions can be specified for initial conditions and mass inlet boundary conditions.


  • Added variable density tutorial.
  • Spread the gas phase reaction source terms when DES_INTERP_ON is True.
  • Additional checks for invalid inputs.
  • Adjusted the verbosity of some error and warning messages.

Notable bug fixes:

  • Fixed out of bound array while writing the DES restart file.
  • Fixed Floating Point Exception in des_thermo_cond_mod.f
  • Always set RUN_TYPE='NEW' when meshing.