Hello, researcher. At present, I want to set the gas inlet of 8 circular arrays on a cylindrical model ( which needs to be expanded to 80 in the future ), and I am implementing it through UDF. At present, the solver has been successfully compiled, but it will report errors after running. I don 't know where the problem is. Please take time to look at it. Thank you.
7_2026-06-15T213044.363426.zip (50.8 MB)
I defined the position and size of the circular array inlets through UDF.
# Boundary condition 10
bc_type(10) = 'CG_MI'
bc_ep_g(10) = 1.0
bc_p_g(10) = 401325.0
bc_t_g(10) = 1223.0
bc_massflow_g(10) = 10.0
CG_MI boundary conditions require a matching STL file. This is why the solver is looking for geometry_0010.stl This would normally be created by the GUI when you set up the BC geometry.
The input file has
#!MFIX-GUI bc_regions = [[[1], ["top"]], [[3], ["all"]], [[4], ["bottom"]]]
so the GUI does not know about region 10. You have a boundary condition without
an associated region. How did you set up this simulation?
– Charles
Since Region seems to define only the plane parallel to the coordinate axis, the curved surface cannot be defined. Therefore, I want to limit the size and coordinates through UDF to define curved surface. It should be clear that I did not add another stl file (geometry_0010.stl). I just wrote the following files.
eval_usr_fct.f (4.1 KB)
In addition, I also tried to import the stl file directly to define these inlets (curved surfaces). Specifically, in Geometry, I imported two stl files, one file is the cylinder body (except the inlets surface), and one file is the inlets surface, which is convenient for me to define the boundary conditions. But the model also encountered problems.Mfix seems to force the mass inflow I set to be converted into a wall. As a result, the model does not have any gas injection.
8_2026-06-16T185633.844829.zip (30.0 MB)