Change rotation axis in mixer_3d

MFiX How to
#1

I’m interested in modelling a powder mixer similar to a granulator. To do this I need to have a vertical shaft. I can see a couple of ways of attempting this, but I can’t get either to work.

The most obvious is just to move gravity and rotate the system in the GUI. The challenge here is getting the particle generator to use the new base as the ‘source’ location. At the moment, I end up with solids piled against one side, and I’m looking at startup and initial mixing so this is no good. Any suggestions for how to persuade the particle generator to start on a different axis?

The alternative is to rotate the equipment so gravity stays in the same direction but I change the orientation of the mixing blades. The problem here is that I can’t work out what I need to change in the UDF so the blades rotate around the y-axis, not the z-axis. Is there a way to do this?

Thanks in advance!
Alan

#2

In usr1_des.f at line 88:

! Rotate STL files        
        CALL Rotate_STL(is_1_group_id, 'Z', cyl_center(:), rot_angle(1))
        CALL Rotate_STL(is_2_group_id, 'Z', cyl_center(:), rot_angle(2))

In this example the rotation is happening around the Z axis, and 'Z' is the second argument to Rotate_STL. I think you just need to change that to 'Y' (and specify the correct center coordinate)

#3

Thank you, Charles!
Not sure how I missed it while looking through the code yesterday