During simulations employing the MPPIC method, the background particles are not visible

MFiX
1

PIC_COALGASFICATION.zip (202.7 KB)
I am using the MPPIC method for simulation, and I would like to visualize the particles set in the background (backgound) using VTK. In my initial conditions (IC), I set the initial particle volume fraction to 0.02. However, after running the simulation, I found that the particles injected through the boundary conditions (BC) are visible in VTK, but the initially set particles in the IC are not. When I switched the simulation method to CFD-DEM, I was able to see the particles defined in the IC. By the way, I’m using MFIX version 25.1.2.

2

If yo look at the output, you should see that there are no parcels in the system:

Generating initial parcel configuration:
  |-------------------------------------------------------------------|
  | IC region:   1                                                    |
  |-------------------------------------------------------------------|
  | Phase | Num. Comp | Num. Real |Statistical|    EPs    |    EPs    |
  |   ID  |  Parcels  | Particles |   Weight  | Specified |   Actual  |
  |-------|-----------|-----------|-----------|-----------|-----------|
  |    1  |         0 |   0.0E+00 |  5.00E+00 |  2.00E-02 |  0.00E+00 |
  |-------|-----------|-----------|-----------|-----------|-----------|
Total number of particles in the system:               0

hence nothing to display.

You have defined a real particle size of 1mm with a statistical weight of 5. The depth of the geometry is 1mm, which means the parcel size is larger than the depth. This is why the initial seeding fails. You should adjust the depth or the particle size so that there is sufficient room for the parcels to be seeded. We should add a data check to catch this inconsistent setting.

3

Thank you for your reply. Your guidance has greatly enlightened me and helped me gain a deeper understanding of MPPIC, which I hadn’t considered before.