[daily_7]

I use DPM to simulate coal particles flow pattern in coal pulverizer. The volume fraction of solid phase is smaller than 8%. The diameters of particles are 0.01-0.1mm. The gas phase use RANS model. Should I consider the effect of turbulence? When can I use the Discrete random walk model?

[2424464575]

Originally Posted by daily_7

I use DPM to simulate coal particles flow pattern in coal pulverizer. The volume fraction of solid phase is smaller than 8%. The diameters of particles are 0.01-0.1mm. The gas phase use RANS model. Should I consider the effect of turbulence? When can I use the Discrete random walk model?

hello，you use the UDF?

[daily_7]

Originally Posted by 2424464575

hello，you use the UDF?

Sorry, no.

[alainislas]

DRW should be enabled with RANS models only. Since in RANS you don't solve for the instantaneous gas velocities, the discrete particles trajectories should include some sort of turbulence. These velocity fluctuations are sampled from a gaussian distribution with standard deviation assuming isotropic turbulence. The model performs quite well in the free-stream region but should be used with caution in the near-wall, especially small particles are prone to exhibit weird behavior

You can read the original work from the 80's by Gosman and Ioannides, from Imperial College