It is recommended that you start with a small under-relaxation factor for the volume fraction, it is also recommended not to start with a patch of volume fraction equal to zero.

Thanks Amina,

Means I should specify volume of the other solid phase in the patch near to zero, but not zero?

How small should be the under-relaxation factor? There is no problem with volume fraction

Best

Muhammad Ali Uzair

Lower under-relaxation factors for the volume fraction equation may delay the solution any value 0.5 or above is adequate.

try it and see if your solution converge

Thank you Amina Benabderrahmane for the advice...

The velocities still don't converge. Can you please have a look..

Chzck these links:

http://www.afs.enea.it/project/neptunius/docs/fluent/html/ug/node762.htm

http://www.engr.uconn.edu/~barbertj/CFD%20Training/Fluent/4%20Solver%20Settings.pdf

Why do you define mass-inflow as boundary condition?

Interesting question

Seifollah Gholampour sorry sir, i didnt understand your question. Is there any problem with mass-inlfow boundary condition?

Muhammad Ali Uzair ...........Good question..

I agree with Amina Benabderrahmane .........

Please share me the best answer might you trust...

Regards…

Amina Benabderrahmane

I have another problem. I am simulating heat transfer in a three phase flow. The issue is when i use 2 granular phases (and 1 continuous phase), it gives temperature discontinuity at the interface of the solid bed region and air.

I have explained the problem in the post in ansys student community forum

https://studentcommunity.ansys.com/thread/evaporation-condensation-model/

Please let me know what I am doing wrong.

Thanks

Even i am facing same problem... convergence is two phase granular approach is very tricky and difficult

@manu ja, can you please explain your problem in detail?

I've read and actually I don't know what you are doing in the case. There are a lot of details in a three-phase flow that can be wrong.

There are many points to be checked.

If the issues start with the energy equation turned on, Verify each setup, and closure model related to it. Are they correct or can be applied to this situation?

Give us more information to help you.

Dear Ricardo

I am simulating reactions using eulerian eulerian multiphase approach, and species transport. When I turn on the reactions after getting the cold flow stable, I get the problem "temperature limited to 1.000000e+00 in 7 cells on zone 2 in domain 3" (Pic attached). I get this problem with the granular phase which is a mixture, not the other granular phase. I reduced the diameter of mixture granular phase from 2 mm to 0.5 mm, but of no use. rest of the details are as follows

2 granular phases

   a) 0.5 mm, mixture

   b) 0.5 mm (not mixture) 

1 continuous phase (mixture)

Geometry:

cell size: 3mm

bottom: velocity inlet (continuous phase)

side: velocity inlet (granular phase a (mixture))

top: pressure outlet

walls: adiabatic, no slip for continuous phase, free slip for granular phases

initial conditions:

sand initial volume fraction: 0.6, Temperature: 1020 K

Air:  temperature: 673 K

Biomass (introduced later when the cold flow is stabilized): 423 K

Drag: air-solid: Huilin Gidaspow

         solid-solid: Syamlal Obrein symmetric

Evaporation-condensation model: Lee

Heterogeneous Reactions: UDF

Homogeneous reactions