[bbmorales]

Dear all

I am modeling a water-solid flow using twoPhaseEulerFoam and would like to discuss some issues regarding drag models with you.

After struggling a bit with some non-physical results, I have decided to run the simplest test I could think of: settling particles.

The description of the system is:
- 2D (1 element in z) 0.20 x 0.60 x 0.01 - uniform mesh with 3 mm x 3 mm elements.
- Water + particles (3 g/cm3, 100 micra)
- Initial condition: uniform - zero velocity, solid volume fraction 0.21.

The model:
- No turbulence
- ppPArticle g0 = 0
- kinetic theory = off
(so basically, the model ignores particle-particle interactions)

The test: GidaspowErgunWenYu drag model x SchillerNaumann drag model

I have allowed the particles to settle for 300s (timestep around 0.01s, Courant under 0.5).

Results (see pics):

- Using GidaspowErgunWenYu absolutely nothing has happened. The particles didn't settle, nothing.

- Using SchillerNaumann, the particles settled and after a while some strange flow in the bottom (which was expected because the lack of a model for accounting for particle-particle interactions at high solid volume fraction).

I have tested also using the GidaspowErgunWenYu model with a higher solid volume fraction (0.40, the rest of parameters unchanged) and got the same result (no settling).

Do you have any thoughts about this? Is this expected for GidaspowErgunWenYu?

Regards!

ps: i am uploading the pics in two batches

[bbmorales]

The previous pics were SchillerNaumann model.

Now, the GidaspowErgunWenYu ones.

cheers!

[vasava]

Have you tested your model with Kinetic theory? If so did you notice any changes in the results.

[Fine]

Hi

Please find attached a case with your specifications that was run with GidaspowErgunWenYu drag model. Settling was obtained in this case.

OpenFOAM V.2.2.1 was used on OS Ubuntu 12.04.

Best regards
Fine