solving flow in axial compressor stages with no convergence

bassamelsayed · October 18, 2022, 20:49

Hi every one, I try to solve a flow inside axial flow compressor stage (IGV, Rotor and Stator). the solver appears to not converge but RMS goes steady and straight fluctuating around 10E-3. i tried several times(200 -400 - 500 - 1000) iterations but i have the same results.
the model inlet conditions is total pressure 1.13 atm. and temperature 288 K, while the outlet is mass flow rate 77 kg/s. the turbulent model is K-E..
Also the efficiency seams that it oscillates and damped with number of iterations.
I wanna to know what may cause this issue and how i can fix it to have converged.

zacko · October 19, 2022, 04:10

First, please, check the maximum Residuals in your output file. These will indicate the domain, where they occur. You can place a point at the exact node number. This will help identify in which region you have convergence issues.

Afterwards, please, recheck your mesh to properly resolve the regions you have encounted that show high residuals.

Maybe you can post an image of your domain setup as well.

ghorrocks · October 19, 2022, 05:10

See FAQ: https://www.cfd-online.com/Wiki/Ansy...gence_criteria

October 19, 2022, 04:10		#2
zacko Senior Member Daniel Join Date: Feb 2017 Location: Germany Posts: 172 Rep Power: 9	First, please, check the maximum Residuals in your output file. These will indicate the domain, where they occur. You can place a point at the exact node number. This will help identify in which region you have convergence issues. Afterwards, please, recheck your mesh to properly resolve the regions you have encounted that show high residuals. Maybe you can post an image of your domain setup as well. Opaque likes this.

October 19, 2022, 05:10		#3
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	See FAQ: https://www.cfd-online.com/Wiki/Ansy...gence_criteria __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

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