I am building a 2D fluidized bed model coupled with flow and heat transfer. The flow-only simulation runs successfully. However, after enabling the heat transfer model, the calculation fails to converge at the initial step. I have tried adjusting the solid relaxation factor, lowering the inlet gas temperature and velocity, but the issue persists. I am unsure whether this stems from incorrect settings in the heat transfer module or other underlying problems. Could you please help check my case files?
Can you try running with explicit coupling enabled (Solids>DEM, check “Enable explicit coupling of interphase quantities”)? I have not run your case to completion yet, but I no longer get the DT<DT_min error at 0.0008s.
Thank you so much for your suggestion! After enabling explicit coupling, the DT < DT_min error no longer pops up at 0.0008s as expected. However, the error still comes back after running the simulation for a while.Do you have any other solutions or suggestions?
Which version of MFiX are you using? I was able to run the simulation for the full 1.0 seconds using both version 25.3 and 26.1 with the only change being
des_explicitly_coupled = .True.
If you still run into the issue with explicit coupling, you can try increasing the MAX_INLET_VEL_FAC as suggested in your attached warning message
Numerics->Advanced->Maximum inlet velocity factor