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Negative power and torque(Axial Turbine analysis)

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Old   December 20, 2011, 23:16
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Sijal Ahmed Memon (turboenginner@gmail.com)
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it seems that the blade is not following the flow or vice versa. Did you use the reference equal to zero or 101325?
On pressure contour plot, scale shows the pressure from 3e+06 to -1e+07, looks strange?
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Old   December 22, 2011, 11:29
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Well things are getting stranger...In the Passages and Alignment section the Passages per Mesh, Passages to Model and Passages per 360 change automatically to 27,27 and 108!
Every time I change them to 1,1 and 4 but as soon as I close CFX-Pre and reopen it they are changed. I am modelling a quarter of a 4 blade turbine so why CFX is changing these parameters?
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Old   December 22, 2011, 11:48
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should not happen, could you please past the snapshot of cfx pre witht the stated problem
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Old   December 22, 2011, 12:23
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Here it is.
Attached Images
File Type: png Passages.png (11.4 KB, 19 views)
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Old   December 22, 2011, 12:27
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make the passage per mesh equal to 1
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Old   December 22, 2011, 12:30
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Quote:
Originally Posted by Far View Post
make the passage per mesh equal to 1
I did this more than 10 times but as soon as I close CFX-Pre it changes again
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Old   December 22, 2011, 12:43
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it is not possible !!!!
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Old   March 27, 2012, 12:48
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Dear one,

I also get this type of problem in Cfx-post.

While i initialize the stator and rotor in Turbo mode.
By default the number of passage in 360 degree is 12 i got, if i change it to 52 in stator and 58 in rotor, but the report generate for turbine shows the mass flow rate as per 12 passage rather than 58 passage for moving bled outlet
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Old   January 23, 2013, 09:20
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Hi,
I'm simulating a Wind Turbine but I don't know the Cp vs lambda curve. I read your post about the net torque procedure. In fluent (ANSYS CFD) I can know the momentum Z (rotation axes) for every blade. This momentum is always positive at different angular velocity:
wind speed = 6 m/s,
angular velocity 10-50-100-150 rad/s
Mz= 0.23 - 4.18 - 6.17 - 6.73 Nm
Is this the net torque?
regards
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