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Negative power and torque(Axial Turbine analysis) |
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December 20, 2011, 22:16 |
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#21 |
Senior Member
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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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December 22, 2011, 10:29 |
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#22 |
New Member
Join Date: Jul 2010
Posts: 23
Rep Power: 16 |
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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December 22, 2011, 11:23 |
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#24 |
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Join Date: Jul 2010
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Here it is.
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December 22, 2011, 11:30 |
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#26 |
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March 27, 2012, 12:48 |
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#28 |
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smith
Join Date: Feb 2012
Posts: 2
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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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January 23, 2013, 08:20 |
NET TORQUE - Fluent
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#29 |
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AG
Join Date: Jan 2013
Posts: 1
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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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July 2, 2018, 05:09 |
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#30 |
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limlibin
Join Date: Jun 2018
Posts: 11
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can i ask if compressor torque negative, which means that is rotor run too fast too?
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July 2, 2018, 06:55 |
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#31 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,819
Rep Power: 144 |
You have to be careful about your definition of positive and negative. But assuming your comment means that a compressor is producing a negative torque (ie a torque in the direction of rotation), that means the compressor is running too slowly and will speed up. So the steady state speed of this compressor is faster than you have modelled.
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Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum. |
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