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-   -   VAWT Wind Turbine (http://www.cfd-online.com/Forums/fluent/40007-vawt-wind-turbine.html)

Tom Smith March 7, 2006 11:24

VAWT Wind Turbine
 
For my Thesis I am modelling a small scale Verictal Axis Wind Turbine in 2D. The turbine has three blades of chord length 0.2m and has a diameter of 2.5m. I am modelling all three blades rotating at 150rpm inside a larger zone using Fluents sliding mesh capability.

I have had a first attempt at solving the model using a relitively coarse mesh. To begin with I solved the flow field in steady-state specifying the rotor as a moving reference frame. I then enebled time dependence and sliding rotor motion using the previous solution as an initial guess for the transient prediction of the flow.

The model now seems to be working. The next stage is to extract performance data. I have tried reporting the torque on the airfoils around the axis of rotation (z-axis), but the torque values are very small and in the wrong direction.

Does anyone have any ideas why my torque values aren't realistic, or comments on my model in general?

Thanks for your help, Tom Smith


yochule April 13, 2009 14:26

hi tom. i hope you are still here.
i am modeling a rotor/stator for a hairdrier. and i am asking about the boundary conditions. how do you do set up the boundary? in your case the rpm of the rotor is funtion of the velocity in the far field. in my case the flow rate (or the velocity) is in funtion of the torque or the rpm of the motor. how can i set up the problem?
regards

panda April 14, 2009 22:56

The torque value is quite dependent on your design and it may be negative or small for a poor design so you need change your design a bit.

salman18q April 16, 2009 15:04

Hey tom...have you had any success yet. I am doing a similar project in 3d.

redlemon April 16, 2009 16:50

Ensure axis is correct for reporting and model is scaled

bima_ap May 17, 2009 09:58

hello tom, my name's bima. I'm new member in this forum. i join this forum because I have the same problem with you. i want to simulate 3 blades airfoil of VAWT and I use sliding mesh too. please help me if you get any solution.

thanx,

sime May 18, 2009 10:59

Hi, tom!
I'm trying to simulate a VAWT as u, but i'm using Turbo Mode in Ansys/CFX. Can we exchange some imformation?

Thanks!

diffy August 1, 2009 02:13

hi tom,,,
i'm doing the same thing as u did for my thesis,,but the turbine is used in water,,I just got the same problem as u,,,the torque values aren't realistic,,,
please help me,,,,

thanks

eng.nassim August 15, 2009 10:51

vwat
 
hi i'm working on VWAT simulation 4 my master now i have begin to try my first mesh using moving mesh to simulate the rotation,s-a 4trublance, unsteady, later i'll try to work on 3d
case. do any one have any case file just to compare with mine
thanks

bennn March 16, 2010 17:40

Quote:

Originally Posted by Tom Smith
;129886
For my Thesis I am modelling a small scale Verictal Axis Wind Turbine in 2D. The turbine has three blades of chord length 0.2m and has a diameter of 2.5m. I am modelling all three blades rotating at 150rpm inside a larger zone using Fluents sliding mesh capability.

I have had a first attempt at solving the model using a relitively coarse mesh. To begin with I solved the flow field in steady-state specifying the rotor as a moving reference frame. I then enebled time dependence and sliding rotor motion using the previous solution as an initial guess for the transient prediction of the flow.

The model now seems to be working. The next stage is to extract performance data. I have tried reporting the torque on the airfoils around the axis of rotation (z-axis), but the torque values are very small and in the wrong direction.

Does anyone have any ideas why my torque values aren't realistic, or comments on my model in general?

Thanks for your help, Tom Smith

I'm carrying out the same kind of project. My approach was to extract the lift and drag force, project them on tangential and normal vector, and then extract torque from the force projected on tangential axis. results are quite good compared with experiment (20% max error with fully stalled airfoil)

skshivas April 1, 2010 02:30

Dear Tom.

Hope now u solve the Problem.

i need u r help for same case.

With Regards

SIVA

desert_1250 August 27, 2011 01:38

Hi
 
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 this 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);


can every one tell me what is the mistaken??


______
Rasoul


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