MFIX-CGP simulation stops at 0.23s with DT < DT_MIN error

MFiX
1

Hi,

I’m running a simulation using MFIX-CGP, and the process consistently stops at 0.23 seconds with the following error:

Error from time_step.f:200
DT < DT_MIN. Recovery not possible!

I’ve carefully reviewed the setup — including the mesh, boundary conditions, time step settings, and physical parameters — and everything seems correct. However, the simulation fails at the same point every time.

Could it be related to a specific solver setting or a physical instability I’m overlooking?

Any help or suggestions would be greatly appreciated.

Thanks in advance!
Reactor_P4.zip (40.3 MB)

2

You get a non-physical solution (negative gas density), which drives the time step down until it reaches the minimum value. This could be due to reaction rates being too large. Please try to turn off all reactions, then turn them back on one at a time. Review the reaction rate settings and adjust if necessary.