Always report errors when using DEM method for simulation

Hello researchers, I have been conducting DEM simulations of chemical reactions recently. I am curious about why this error always occurs.

I set the parameters based on examples uploaded by others on the forum, and the results have been consistently reporting errors. I don’t know where the problem lies. I have provided an error report and I hope you can help me take a look and point out the problem. I would greatly appreciate it if this issue could be resolved. (7.1 KB)

Access violations typically mean a particle has left the domain. This can be due to poor mesh quality or particles/walls which are too soft.

Hello, I have checked the grid quality, and it is also quite good. Is there any other reason? I have uploaded the error report. Would it be convenient for you to take a look?

In addition, I have also made settings for this location, and it is still an error report.

I ran your case with the latest MFiX code - this is 23.3 which will be released next week - it has improved checking for particles out of bounds. I got this message:

Error: There exists a NORMAL particle in a GHOST cell.
Particle may have gone OUT-OF-BOUNDS.
To resolve this issue, please consider:
 a) Verify all wall boundary conditions are defined
 b) Reducing the value of the variable NEIGHBOR_SEARCH_N (Solids>DEM>Max steps between neighbor search)
 c) Increasing the particle and/or wall stiffness (Solids>DEM>Normal spring constant or Young's modulus)
Current particle location (x, y, z coordinates):-0.1012E-02,  0.1933E-01,  0.1000E-02
Current particle velocity (u, v, w components) : -47.17    ,  -69.66    ,  0.2685E-14

It runs fine when I turn off reactions. Maybe you are generating to much gas and it pushes particles out of the domain too fast. Please check your reaction rates, my guess is they are too large.

Thank you for your prompt reply. I will try again.

Thank you for your prompt response. I tried to reduce the chemical reaction rate, but there was an error DT<DTmin. What should I do?

By how much did you reduce them? You may need several orders of magnitude reduction to make a difference. I would start with zeroing out all reactions and start turning them on one at a time. Check the values of the reaction rates and do a hand calculation to see what you should expect.

Thank you very much for doing so. I will always be waiting for your reply.