I am trying to use the PDF transport model to simulate a 3-d bluff body combustor. This is for turbulent combustion. I have ran a few cases but each time the residuals diverge after approximately 40 time steps. I have tried two different mixing models (EMST and IEM models) I have also tried 2 different values for particles per cell (10 & 20). Admittedly I am not very familiar with this model so any adivce or knowledge would be welcome. If anyone needs more information about the case please feel free to ask. Thank you all very much in advance.

Are you using enhanced wall treatment?

No i am not using enhanced wall treatment. Could that be the reason for the divergance?

It may have been if you were using it.

By time steps do you mean time steps or iterations?

If you are running unsteady try steady.

If you are running steady try setting it up using the EDC model. The equilibrium non or partially premixed models are best to set the EDC up. Look at the user guide.

When you say diverged do you mean it actually crashed or just that it didn't converge? Are you getting values being limited in cells?

Hope this helps, but you might already be doing these things.

Phil