Insufficient Granular Settling
 

Hello all,

I am having difficulty achieving realistic solids settling. I am trying to simulate water carrying sandstone granules (1/4 inch diameter) in the annulus between to pipes (OD's of 8 in and 4.5 in). According to experimental data, at the flow rate I am using (200 gpm), approximately 210 lbs of sandstone should be in a 25 ft section at stead state. I am getting about 5 lbs in Fluent.

I am using Fluent 14.5, and I am using the Euler multiphase model with a granular second phase. Also, I am using the Reynolds Stress dispersed viscosity model. I have seen papers describing issues with drag coefficients, so I am using the Gidaspow drag model with the Brucato drag factor modification. I have also tried several turbulent dispersion models with no luck.

Does any one have any advice to help me achieve a more realistic simulation?

Thank you in advance.

Check in the phase interaction panel, there are various options for different other forces that can be used like turbulence dissipation etc.
Try changing them and lets see if you may have some luck.
regards
shk