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centrifugal compressor - simulation - no compression

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Old   November 29, 2015, 09:48
Default centrifugal compressor - simulation - no compression
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Bartek
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Hello all,
this is my first post so I apologize in advance for any errors and my English.
For several months, I try to simulate the real engine compressor.
The compressor has been scanned 3D, then in SE machined surface, created inlet and an outlet, all as a solid model
scan.jpg
se model.jpg


Then, in ANSYS design modeler, I called all the walls, freeze, and I set the in Details Viev as fluid
1.jpg

I made mesh
Attachment 43824

In the CFX settings, intake as stationary, rotor as rotary and outake as stationary.
analysis type -transient or staty state- result is the same.
in the details of fan : domain type-fluid domain, air at 25C, reference pressure 1 atm.
In the inlet m I set up, the static pressure of 1 atm, the total pressure of 1 atm, the mass flow rate of 2.03 kg / s.
In the outlet, also I tried to set static pressure/total pressure 8 atm, pr mas flow rate 2.03 kg/s.

3.jpg

After several attempts, the results are always the same, does not get compress. Pressure in all compressor is constantly.
4.jpg

Please help me,
Bartek
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Old   November 29, 2015, 18:11
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Glenn Horrocks
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I can see your mesh is WAY too coarse. You will need a much finer mesh.

Try that and see what happens - there are probably other problems to fix as well.
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Old   November 30, 2015, 16:29
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I tried many times to create a mesh and These mesh, was the only one who correctly has formed and has allowed for further analysis. In my opinion, the problem is somewhere in the settings in the pre-CFX : inlet/outlet or interfaces.
PS. on the the first picture, this isn't mesch. This is result of 3d scanning. The compressor model consists of a many surfaces being the whole model
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Old   November 30, 2015, 16:59
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Can you show an image of your mesh?

Also please post your CCL and/or your output file.
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Old   November 30, 2015, 17:56
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Ofcourse, but tomorrow. At this moment, CFX-solver is running.
CCL what do You mean?
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Old   November 30, 2015, 19:31
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In CFX-Pre, go File/Export/CCL. It is the command file which describes the simulation setup and physics. It is a small text file.
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Old   December 1, 2015, 14:56
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The result of the last calculations
result.jpg


Now there is some compression but totally strange Types


And the mesch
mesch.jpg
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Old   December 1, 2015, 19:34
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That mesh is way too coarse. You will need to refine it.

Also I can see recirculations and other weird stuff in your streamlines. This means:
* Your device is operating way off its operating point and therefore the streamlines are recirculations. Then it is correct in saying it produces no compression.

AND/OR

* Your simulation is not converged yet, you need to converge it more to pull those recirculations through the simulation.
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Old   December 2, 2015, 14:12
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And CCL file
compressor.zip
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Old   December 2, 2015, 19:00
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You appear to be trying to do a compressible gas simulation, but you have not chosen a fluid model which has variable density. You should choose a fluid model which has variable density, such as Air (Ideal Gas).
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