EDEM-FLUENT coupling error with polyhedral particles

phamad

 

Hi everyone,

I am trying to simulate a fluidized bed reactor to evaluate the effect of different particle shapes. The same simulation setup (only different particle shape) run very well with multi-spherical particles but not with polyhedral particles.

At the initial time when the particle volume fraction is not high (released from a factory),  FlUENT (with DDPM turned on) ran smoothly. As time goes on, the particle volume fraction got higher (e.g. more particles at the bottom), the continuity equation in FLUENT is gradually hard to converge, and then "floating-point exception error" appeared. 

FYI: I used EDEM 2021.0 & FLUENT 2021R2. For more information about its setup, please check the attached files.

 

Thanks for your reading.

 

RWood

Hi,

The most likely issue that I can think of relates to the volume fraction, which you already mention. The particle volumes need to be smaller than the mesh cell volumes, so if the particles end up in a boundary layer cell then you will probably hit issues.

One thing you can try is enabling node based smoothing in Fluent. I think this is within the DDPM options (from memory) where it tries to smooth out the particle source terms to adjacent nodes. That can sometimes help avoid issues with high volume fractions.

Failing that, the most surefire solution is to either reduce the particle size or increase your mesh cell size. It might be worth doing this as a test anyway, to check that this is the issue you're facing.

Cheers,

Richard

phamad

Richard Wood_20774 said:

Hi,

The most likely issue that I can think of relates to the volume fraction, which you already mention. The particle volumes need to be smaller than the mesh cell volumes, so if the particles end up in a boundary layer cell then you will probably hit issues.

One thing you can try is enabling node based smoothing in Fluent. I think this is within the DDPM options (from memory) where it tries to smooth out the particle source terms to adjacent nodes. That can sometimes help avoid issues with high volume fractions.

Failing that, the most surefire solution is to either reduce the particle size or increase your mesh cell size. It might be worth doing this as a test anyway, to check that this is the issue you're facing.

Cheers,

Richard

Hi,

If you check my pre-set files, you can see the all CFD mesh cell volumes are bigger than the particle volumes.

Anyway, I have solved the problem now. I realized that the "lib_edem_coupling" folder was compiled for EDEM 2021.1-Fluent 2021R2, then I tried to compile again for EDEM 2021.0-Fluent 2021R2, and no problem at all!

Thank you very much for your support.

Regards,

Pham