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MFiX 21.3 Release Announcement

Dear MFiX user,

We are pleased to announce the MFiX 21.3 release. Please download the latest version. See the release notes 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 the Guo-Boyce friction model [1]. This model was graciously provided by researchers from Columbia University, NY. Specials thanks to Dr. Guo and Dr. Boyce for their contribution!
  • Support for Shared Memory Parallel (SMP) solver on Windows OS.
  • Residence time tracking for particles/parcels (vtp files and monitors).
  • Movie making tool for making movies (*.mp4 with ffmpeg) from the current visualization window or selected image stack.


  • Exposed TMIN and TMAX (minimum and maximum temperatures) in the GUI.
  • Added a data check in the GUI to prevent setting overpacked regions.
  • Improved message dialog, scroll through solver messages with arrow/tab keys.

Notable bug fixes:

  • Fixed bug in particle rates output keyword.
  • Fixed bug in setting up geometry with implicit functions.

[1] Qiang Guo, Yuxuan Zhang, Azin Padash, Kenan Xi, Thomas M. Kovar, Christopher M. Boyce, "Dynamically structured bubbling in vibrated gas-fluidized granular materials", Proceedings of the National Academy of Sciences Aug 2021, 118 (35) e2108647118; DOI: 10.1073/pnas.2108647118

From 21.3.0 to 21.3.2

Bug fixes

  • Fixed Reactionrates not visible as vtk output
  • Fixed failure to mesh some complex geometries with 21.3 default solver on Windows
  • Fixed DES mass flow rates monitors

Cosmetic/workflow changes:

  • Allow to set the solids volume fraction at onset of friction (eps_f_min) for the Guo-Boyce frictional stress model
  • Hide werkzeug shutdown function deprecation warning
  • Fixed layout problem in monitor pane
  • Fixed 'QMoveEvent' object has no attribute 'modifiers' error