Learning Forum

[youssef.badran]

Hello,

I would like to simulate a fluidized bed containing two types of particles using ANSYS Fluent.

Could you please confirm whether it is possible to define one gas phase and two solid phases within the Eulerian granular multiphase model? In addition, how can the interactions between the two solid phases be handled?

Is there any tutorial or reference related to modeling this type of polydispersed system?

[Rob]

It is possible. Phase interactions are handled in the Phase panel (Interactions tab) as normal as Fluent considers the granular phase(s) as a pseudo solid. 

There aren't any tutorials on the public side that I'm aware of, but for the most part just use a "normal" two phase granular set up. Note, Fluent does not have any packing limit maths to handle multiple granular phases so you may need to do some thinking if the phases are very different in size. We'd typically use Rocky for that sort of thing. 

[youssef.badran]

Thank you very much for your reponse. I tried a fluidized bed simulation with one solid phase and it worked well. However, when I added a second solid phase, I got the error below. Could you please inform me what could be the reason of this error ?

Updating solution at time levels N and N-1.

done.

iter continuity u-gas u-graphite u-magnesiu v-gas v-graphite v-magnesiu w-gas w-graphite w-magnesiu k omega vf-graphit vf-magnesi time/iter

Stabilizing mp-x-momentum to enhance linear solver robustness.

Stabilizing mp-y-momentum to enhance linear solver robustness.

1 1.0000e+00 3.6455e-05 7.5236e-18 1.8579e-16 7.1596e-01 6.9648e-15 1.2404e-14 1.3287e+00 3.9382e-01 1.8136e-01 8.2903e-05 2.2206e+04 1.3902e-05 7.2488e-06 0:00:02 19

2 1.0000e+00 1.7355e-01 5.7971e+03 4.8682e-04 3.4626e-02 3.5712e-05 3.4968e-05 2.6352e+01 2.3577e-02 2.3125e-02 2.4241e-01 5.0567e-01 2.3144e-03 4.5409e-03 0:00:06 18

Reversed flow on 20 faces of pressure-outlet 6.

3 6.5986e-01 1.8518e-02 8.1361e-05 1.8741e-05 4.7377e-03 4.6597e-05 3.6911e-05 3.2614e+00 3.1621e-03 2.8407e-03 6.9350e-02 3.6028e-01 1.4702e-03 4.1112e-03 0:00:05 17

Reversed flow on 32 faces of pressure-outlet 6.

Stabilizing mp-x-momentum to enhance linear solver robustness.

Stabilizing mp-x-momentum using GMRES to enhance linear solver robustness.

Stabilizing mp-y-momentum to enhance linear solver robustness.

Stabilizing mp-y-momentum using GMRES to enhance linear solver robustness.

Stabilizing mp-z-momentum to enhance linear solver robustness.

Stabilizing mp-z-momentum using GMRES to enhance linear solver robustness.

Stabilizing pressure correction to enhance linear solver robustness.

Stabilizing pressure correction using GMRES to enhance linear solver robustness.

Divergence detected in AMG solver: pressure correction Stabilizing k to enhance linear solver robustness.

Stabilizing k using GMRES to enhance linear solver robustness.

Divergence detected in AMG solver: k Stabilizing omega to enhance linear solver robustness.

Stabilizing omega using GMRES to enhance linear solver robustness.

 

Divergence detected in AMG solver: omega Stabilizing vof-1 to enhance linear solver robustness.

Stabilizing vof-1 using GMRES to enhance linear solver robustness.

Divergence detected in AMG solver: vof-1 Stabilizing vof-2 to enhance linear solver robustness.

Stabilizing vof-2 using GMRES to enhance linear solver robustness.

Divergence detected in AMG solver: vof-2

Divergence detected in AMG solver: pressure correction

Divergence detected in AMG solver: k

Divergence detected in AMG solver: omega

Divergence detected in AMG solver: vof-1

Divergence detected in AMG solver: vof-2

Divergence detected in AMG solver: pressure correction

Divergence detected in AMG solver: k

Divergence detected in AMG solver: omega

Divergence detected in AMG solver: vof-1

Divergence detected in AMG solver: vof-2

Divergence detected in AMG solver: pressure correction

Divergence detected in AMG solver: k

Divergence detected in AMG solver: omega

Divergence detected in AMG solver: vof-1

Divergence detected in AMG solver: vof-2

Error at Node 2: floating point exception

Error at Node 0: floating point exception

Error at Node 3: floating point exception

Error at Node 1: floating point exception

Operation stopped.

[youssef.badran]

It seems that the reason of the error is that I initialized the first half of the particles bed with the first solid phase and the second half with the second solid phase but these two regions were overlapping. I separated these two regions and it seems to work.