Mixsim2: Cannot have more than 8 impellers on the same shaft
When more than eight impellers are attached to the same shaft, MixSim fails most often to create a mesh.
Other features of MixSim are probably also affected by this bug.
This problem is in fact more general:
Any object in the model may not have more than 8 children (child objects)
If the number of children is larger, equation parameter definitions in the ninth, tenth, thirteenth, and probably more children will fail to work. Note that the ordering of objects changes when you save and re-load (in a new session) the model file!
The following approach MAY allow you to at least have MixSim create the mesh. The automatic definition of boundary conditions (which is done as soon as your start iterations) may still fail, so please use this workaround with caution, and check the mesh, its zones, and all boundary conditions carefully..!!
A workaround that has been found to work for the mesh generation (ONLY in that case!) is the following:
In the GUI, for ALL impellers, check ALL parameter values that are displayed on grey background because they have been defined through an equation (using the calculator panel). If the values are not correct (or if an error message is displayed instead of a value), remove the complete equation and replace it by an appropriate explicit value.
You will have to do this again after you've saved and reloaded the model in a new MixSim session, because the internal ordering of the object in MixSim is important, and it changes when you save and reload the model (in a new MixSim session).
NOTE: By using this approach, the mesh generation MAY succeed. But please check the mesh and its zones. AND, particularly important, check ALL boundary conditions settings MixSim does automatically -- they may be wrong and (even more likely) Incomplete!
Finally, you may never expect the generation of "impeller surfaces" to work in this case -- it will not. (Because that uses some *hidden* parameters that are defined through equations.)