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High torque coefficient Cm for Vertical Axis Wind Turbine (VAWT) |
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February 28, 2010, 08:33 |
High torque coefficient Cm for Vertical Axis Wind Turbine (VAWT)
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#1 |
New Member
Join Date: Nov 2009
Posts: 22
Rep Power: 17 |
Hello,
I am modelling the 2D vertical axis wind turbine (VAWT). The turbulence model is k-epsilon with std wall function. I simulate 4 angular velocities: 5, 10, 15 and 20 rad/s. Wind velocity is 11 m/s. Model is using U-RANS with sliding mesh. Problem is that I obtain excessively high torque calculated from the Cm (4 to 5 times larger than it should be). Cm is obtained from Fluent, torque calculated with the Cm definition(Cm=T/(0.5 x rho x v^2 x A x R). Time step: tried both time steps corresponding to 1 degree and 1/8th degree. Results perfectly match so the 1deg step is fine enough. I would be very grateful to the one who can spot if and/or where I am making a mistake and can contribute to making this simulation happen the best way. Thanks All the best TonyMac Last edited by tony00; March 17, 2010 at 06:25. Reason: wrote seconds instead of degrees to define the angular step increment |
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March 16, 2010, 17:34 |
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#2 |
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benoit paillard
Join Date: Mar 2010
Posts: 96
Rep Power: 16 |
that might sound - and actually be - silly but check that you actually divided the torque by the appropriate value, to get a reduced coefficient instead of a Nm torque. That happened here not too long ago.
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March 19, 2010, 09:26 |
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#3 |
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Join Date: Nov 2009
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Hello Benoit,
all solved and getting pretty good results now. As you suggested it was indeed a problem with the constants entered in report-> reference values. Thanks Tony |
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March 22, 2010, 23:43 |
Change fluent reference values
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#4 |
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Haris Hameed
Join Date: Oct 2009
Posts: 48
Rep Power: 17 |
Change fluent reference values
compute velocity form inlet and change reference area to swept area your cm will change hope this work |
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April 1, 2010, 01:59 |
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#5 | |
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SHIVA
Join Date: Feb 2010
Posts: 7
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Quote:
I m also facing the same problem. still i m not able to reasolve the fluent case. please give some idea to predict the Torgue and Co efficient of the performance (Cp) of the wind Turbine. With Regards S.SIVAKUMAR |
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June 11, 2010, 06:15 |
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#6 |
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Hi tony, maybe I'm affected by the same problem you solved.
I hope you will share with me your solution. Thanks |
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February 21, 2014, 01:07 |
Doubt
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#7 |
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dynamic
Join Date: Oct 2013
Posts: 3
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In the Cm definition, what is A(area)?
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March 25, 2014, 02:56 |
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#8 |
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June 2, 2014, 03:25 |
high value of Cm
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#9 | |
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Aalisha
Join Date: Jan 2014
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Quote:
-Aalisha |
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January 9, 2015, 23:27 |
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#10 |
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Join Date: Jan 2015
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For a 2D case should I take the area = 1, and in this case what should be the depth.
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March 27, 2017, 02:51 |
CM coefficient
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#11 |
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nima seyfi
Join Date: Feb 2017
Posts: 3
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hi
can anybody help me please what is A and L in equation of CM blow: cm=M/0.5*RHO*U^2*A*I my case is a vertical axis wind turbine archimedes spiral wind turbine blade |
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July 23, 2018, 07:13 |
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#12 |
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UTTAR PRADESH
Join Date: Jul 2018
Posts: 1
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