CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > FLUENT

Torque calculation of 2D VAWT Wind Turbine

Register Blogs Members List Search Today's Posts Mark Forums Read

Like Tree1Likes
  • 1 Post By Anonymized_JL1

Reply
 
LinkBack Thread Tools Display Modes
Old   September 19, 2010, 02:37
Default Torque calculation of 2D VAWT Wind Turbine
  #1
New Member
 
Join Date: Feb 2010
Posts: 24
Rep Power: 7
Anonymized_JL1 is on a distinguished road
Hello Everyone,

I am working on my Thesis which is basically 2D CFD simulation of Vertical Axis Wind Turbine. I need to calculate the torque generated by a wind turbine in order to find Cp. In this regard I am running 2D simulation with sliding mesh technique and saving the case/data file after every 10 degrees of rotation hence I have 36 files for one complete revolution. Now I am reporting the value of forces in X and Y direction (Fx and Fy) from each case/data file for all 3 Blades. Then I calculate Torque on each blade using formula
T1 = - Fx1.RcosΘ - Fy1.R.sinΘ
T2 = -Fx2.Rcos(Θ+120) - Fy2.R.sin(Θ+120)
T3 = -Fx3.Rcos(Θ+240) - Fy3.R.sin(Θ+240)
Total Torque T = T1 + T2 + T3 (Total Torque “T” is calculated for every 10 degree of rotations)

Average Torque = Σ T/n (0-360 degrees) where n = 360/10 = 36
Please let me know if the method I am using is correct. I am confused about the sign convention of Torque equations. is there any other way to find out Torque and Cp(Coefficient of performance)?
Attached Images
File Type: jpg Velocity Contours.jpg (21.6 KB, 614 views)
File Type: png Zoomed in view of Rotor.PNG (30.2 KB, 651 views)
anindito likes this.

Last edited by jola; January 5, 2012 at 12:02.
Anonymized_JL1 is offline   Reply With Quote

Old   September 20, 2010, 01:15
Default
  #2
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 2,991
Rep Power: 30
-mAx- will become famous soon enough
in Fluent you can compute moments (torque)
Report/Forces... choose Moments instead of Forces.
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   September 20, 2010, 19:57
Default
  #3
New Member
 
Join Date: Feb 2010
Posts: 24
Rep Power: 7
Anonymized_JL1 is on a distinguished road
Thanks for your reply. I tried to report the moment in fluent but its all negative. is it cuz my Turbine is rotating in counterclockwise direction? do I have to sum them all up to get the total torque (M= M1+M2+M3) for angle 0-360 degrees?

Thanks
Anonymized_JL1 is offline   Reply With Quote

Old   September 21, 2010, 02:31
Default
  #4
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 2,991
Rep Power: 30
-mAx- will become famous soon enough
If you compute the moment you should give the right axis.
if you set the angular velocity, you should give the right direction (axis-convention)
And yes, if all your moment are computed on the same point, you can add them
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   November 20, 2010, 11:06
Default Asking for help!!
  #5
New Member
 
Low Chee Boon
Join Date: Nov 2010
Posts: 3
Rep Power: 6
Boon is on a distinguished road
Hi , friend ! im new for Fluent, i also want to get the data from VAWT after simulation. but i dont know how to build up 2D drawing in Fluent. Can you guide me how to build it up in fluent ?
Boon is offline   Reply With Quote

Old   August 27, 2011, 01:42
Default
  #6
Member
 
s.rasoul_varedi
Join Date: Feb 2010
Posts: 82
Rep Power: 6
desert_1250 is an unknown quantity at this point
Send a message via Yahoo to desert_1250
Quote:
Originally Posted by -mAx- View Post
If you compute the moment you should give the right axis.
if you set the angular velocity, you should give the right direction (axis-convention)
And yes, if all your moment are computed on the same point, you can add them

Hi Max, how are you? i hope that you are well
i simulated 2d VAWT successfully with OF (ggi method) and get the good result for mummentum as expected.
after that i decide to simulate it in 3d Geometry. so i create the 3d geometry and Mesh in Gambit and import it to OF, every thing is ok and i stop the run after 50 rotation degrees. when i see contours of velocity or pressure, every things is ok, but when i extract the mummentum, the result is very bad!!!??? why this happen???
for calculate the forces and mummentum for every blade i added similar code in controlDict file :
forces_1
{
type forces;
functionObjectLibs ("libforces.so");
outputControl timeStep;
outputInterval 100;
patches (Blade1);
PName p;
Uname U;
log true;
rhoInf 1.2;
CofR (0 0 0);



______
Rasoul
desert_1250 is offline   Reply With Quote

Old   August 29, 2011, 01:42
Default
  #7
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 2,991
Rep Power: 30
-mAx- will become famous soon enough
adapt CofR (0 0 0) coordinates.
They are needed for torque computation
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   August 29, 2011, 04:07
Default
  #8
Member
 
s.rasoul_varedi
Join Date: Feb 2010
Posts: 82
Rep Power: 6
desert_1250 is an unknown quantity at this point
Send a message via Yahoo to desert_1250
How to adapt CofR (0 0 0)? i set it at center of rotating object
desert_1250 is offline   Reply With Quote

Old   August 29, 2011, 04:08
Default
  #9
Member
 
s.rasoul_varedi
Join Date: Feb 2010
Posts: 82
Rep Power: 6
desert_1250 is an unknown quantity at this point
Send a message via Yahoo to desert_1250
How to adapt CofR (0 0 0)? i set it at center of rotating object

_____
Rasoul
desert_1250 is offline   Reply With Quote

Old   August 29, 2011, 04:12
Default
  #10
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 2,991
Rep Power: 30
-mAx- will become famous soon enough
It should be the a point on your rotation axis
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   August 29, 2011, 04:36
Default
  #11
Member
 
s.rasoul_varedi
Join Date: Feb 2010
Posts: 82
Rep Power: 6
desert_1250 is an unknown quantity at this point
Send a message via Yahoo to desert_1250
would you mind to seee this froum(from post 8):
Wind driven rotation
i set my result for 2D and 3D VAWT and case in it. i think that i chose the point on the rotation axis

______
Rasoul
desert_1250 is offline   Reply With Quote

Old   August 29, 2011, 04:47
Default
  #12
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 2,991
Rep Power: 30
-mAx- will become famous soon enough
do you think or are you sure?
If you go back to your mesher, check if (0 0 0) belong to your rotation axis.
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   August 29, 2011, 05:23
Default
  #13
Member
 
s.rasoul_varedi
Join Date: Feb 2010
Posts: 82
Rep Power: 6
desert_1250 is an unknown quantity at this point
Send a message via Yahoo to desert_1250
now i am surely chose the point at the center of axis. i check it witj mesher and paraview? did you see my result and pic that set in the mentianed froum in the last post?

_______
Rasoul
desert_1250 is offline   Reply With Quote

Old   August 30, 2011, 04:48
Default
  #14
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 2,991
Rep Power: 30
-mAx- will become famous soon enough
check if pressure distribution on blades are the same on 2d and 3d
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   September 26, 2013, 03:35
Default
  #15
New Member
 
Michael Bausas
Join Date: May 2013
Posts: 10
Rep Power: 4
mikebausas is on a distinguished road
Anonymized_JL1, good day! I am also working on a three bladed VAWT for my thesis.. I am currently building my gemometry and mesh using ICEM CFD. I started with a 1/3 portion of the turbine and had generated its unstructured mesh.. Do u have any suggestion on how to go on with my meshing from this point? How shall I generate the other two parts and how to merge them into a whole rotor. Please help. Thanks in advance..
mikebausas is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
High torque coefficient Cm for Vertical Axis Wind Turbine (VAWT) tony00 FLUENT 9 January 9, 2015 23:27
Torque of wind turbine simulation caohan FLUENT 8 August 11, 2014 23:01
VAWT Wind Turbine Tom Smith FLUENT 11 August 27, 2011 01:38
help to find torque of a wind turbine using fluent athiyaman.p FLUENT 1 March 10, 2006 11:49
Warning 097- AB CD-adapco 6 November 15, 2004 05:41


All times are GMT -4. The time now is 05:54.