SimScale CAE Forum

Axial compressor simulation - Max iterations reached

I’ve been trying the get the hang of SimScale over the past few days by trying to do some fluid dynamics analysis on an axial compressor, I’ve tried 3 different geometries, tonnes of different meshes, and a whole lot of changes to the numerics but I keep getting a ‘max iterations reached’ error, the residual plot has changed as I’ve tried more fixes but currently only my epsilon residual is decreasing. No simulation has passed 3% yet.

Trying to model an axial compressor (Originally I used moving walls but I dropped it since I figured they may have been giving my ‘max iterations’ issues)
Inlet -> 40m/s air flow
Outlet -> 15bar

I feel like there’s one little obvious thing I’m doing wrong but I’ve changed the other relaxation factors as recommended by other tutorials. If anyone could give it a look I would really appreciate it.

Originally I was having errors with my epsilon residual being the only one not decreasing but as in the failed ‘run 1’ now epsilon is the only residual that is decreasing.
Run 1 is a failed run using k-epsilon
Run 2 is a quick run that I’m doing now, the convergence plot shows that It will likely fail

Also just a heads up this isn’t my can file, I got it form the link in the description

Thanks guys

Hi @JacksonEmpey!

First of all you are using a tet-dominant mesh but you have to use SnappyHexMesh (Hex-dominant parametric) for problems related to fluid dynamics. Furthermore I want to know if you have another model with which we can create a separate rotating zone because the model you provided us with is not closed and cannot be used properly for the simulation (assuming that you want to have a flow inlet, a rotating domain around your impeller as well as a flow outlet.

I think if you fix the issues for the pre-processing step we are on a good way to achieve good results. If you need any further help please let the @PowerUsers_CFD, @Anware and me know!

All the best!



Thank you! I’m in the middle of exams now but when I have a minute I’ll give it a try!
Much appreciated!

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