Unsolvable convergence problems (TFM, 2D spouted bed)

Hi everyone!
I’m sorry for taking up your precious time.
I created a 2D conical spouted bed under the TFM model.When I simulate particle flow, the mfix prompt does not converge.I found the sentence “Run diverged/stalled :frowning: Recovered: Dt= 0.28243E-03 :-)” in the log.I checked the mfix guide and mfix forum and found some solutions.I have tried the following measures:
(1) Modify the time step; (2) Increase the number of iteration steps; (3) Change the discrete method; (4) used a line preconditionner; (5) turned off the stall detection;(6)Reduce underrelaxation factors;(7)Removing small cut-cells.
However these measures did not solve my problem.
This problem bothered me for a long time.I can’t find a working solution.I attached the case.
test3.mfx (17.3 KB)
How can I fix this non-convergence problem? I sincerely look forward to your reply!

First, double check the packed bed void fraction. The value you used of 0.98 is unusual. You may also start with a fluffed bed instead of a packed bed.

For the numerical settings, use the default tolerance (tol_resid) of 1E-4 instead of lowering it to 1E-5. Then increase the number of gas pressure equations to 200 (Numerics>Linear solver).

You may also consider using ideal gas law for the gas density instead of incompressible fluid.

Thank you very much for your reply.I successfully solved the divergence problem as you suggested.This case is working normally.
I found the value of the bed void ratio from the article. I may have misunderstood this value.
Thanks again for your reply!

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