Hello,researchers. I am doing research on MFIX-CGP. However, particle output is not written out. I’d be grateful if you could assist me with this matter. Thank you very much.
0728-CGP.zip (98.2 KB)
In the VTK interface, only the fluid phase is rendered, whereas the particle phase remains invisible. Could this be due to a visualization setting or a data issue?
If you want help you need to attach your project files. Go to the main menu, select “Submit bug report” and upload the ZIP file here.
When I click ’ Submit bug report ', the interface has been like this picture.
The formed zip file is as follows.
cgp_2025-08-12T231017.607478.zip (763 Bytes)
Sorry, this is a bug in MFiX 25.1 which has been corrected in MFiX 25.2. And I see that you have already attached your files in your first post.
I can verify that the GAS.* files are being written, while the expected PARTICLE.* files never appear. Also there is a fort.80 file which is usually a sign that something has gone wrong. I don’t know exactly what the problem is, I will take a look at this and get back to you. Thank you for your patience.
– Charles
Thank you so much, I truly appreciate you taking the time to look into this.
For more, when I use the MFIX-DEM model, the particle file can be written out. However, when I used the MFIX-CGP model, the particle file was not written out.
Here’s at least a partial answer: the particle data file is not written when there are no particles in the system. Your initial condition has solids volume fraction of zero.
If I start with a single particle, the file is writtten:
There should be particles coming in the top mass inlet, but it seems that the rate is very slow:
For mass inlet BC: 5
Boundary Area = 4.8000E-01
Total no. particles injected per solids time step = 7.70769618E-02
Total no. particles injected per second = 36
PI_FACTOR = 1.29740458E+01 PI_COUNT = 1
Start DES_MI_TIME = 2.72707704E-02
Uniform inlet velocity = 1.0000E-01
For each solid phase,
For solid phase 1:
No. particles injected per solids time step = 7.70769618E-02
No. particles injected per second = 36
Calculated inlet velocity = 1.0000E-01
We’re only injecting 36 particles per second, and the number of particles injected per time step is 0.07, so the injection may not be happening at all. This may only be a problem with CGP.
– Charles
Thank you for your answer.If I want to keep the top mass inlet velocity constant, what adjustments should I make to write the particle file
You just need to run the simulation long enough so that particles enter the system. Please note that particles are injected in a staging area above the top inlet so there may be a small delay until particles travel down into the fluid region.