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January 5, 2008, 06:30 |
transonic rotor convergence problem
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#1 |
Guest
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Hi all,
I faced same convergence problem as posted before by Samad in this forum, with an indication that the maximum Mach number increase too much. I have used CFX-TurboGrid 11.0 for mesh generation and the Turbomachinery template for the CFX-PRE 11.00 I want to know if somebody have successful to get a convergence with a transonic compressor (rotor37 i my case)? and if yes, plz, tell how you did it ? any other advice is welcome Regards Noureddine |
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January 6, 2008, 06:59 |
Re: transonic rotor convergence problem
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#2 |
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even I try to simulate the off-design flow (60% of design speed = 1080 rad/s) to have a subsonic axial compressor, I found same difficulty to converge. I used P-Total Inlet Mass Flow Outlet as boundary conditions, with, Reference Pressure = 1 atm, P-total = 0 atm, Mass Flow rate per Machine = 13.9 kg/s.
what is the problem ? any help is very welcome. Regards Noureddine |
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January 6, 2008, 12:20 |
Re: transonic rotor convergence problem
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#3 |
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It's OK, i found my mistake, it was the direction of rotation !!!!, we should indicate the sign of the rotation as -1800 rad/s for the design speed.
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January 6, 2008, 18:23 |
Re: transonic rotor convergence problem
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#4 |
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Hi Noureddine,
Well i know you solved your problem but i have a small question. I am simulating a rotor in a stator (journal bearing) using turbomachinery template in CFX 11. I have a lubricant between my rotor and stator...When i do a transient simulation the residuals oscillating. did you have the same problem how did you solve it? |
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January 7, 2008, 02:42 |
Re: transonic rotor convergence problem
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#5 |
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Hi Amir,
yes i had an oscillation of residuals in the last steps, but results was acceptable. sorry, i have solved only the steady flow of a transonic compressor and i did not deal with the transient rotor/stator simulation. Good luck Noureddine |
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January 8, 2008, 08:46 |
Re: transonic rotor convergence problem
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#6 |
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Hi Noureddine!
the negative sign is for your rotors rpm,which is not always common,it specifies the direction of rotation. |
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January 8, 2008, 09:23 |
Re: transonic rotor convergence problem
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#7 |
Guest
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Hi Pankaj,
i know that's not always common, i am talking only about my own problem (own geometry) which is the axial compressor "rotor37". you are right, it specifies the direction of rotation. thanks for you message. Regards. Noureddine |
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