# VAWT Wind Turbine

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 March 7, 2006, 11:24 VAWT Wind Turbine #1 Tom Smith Guest   Posts: n/a Sponsored Links 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

 April 13, 2009, 14:26 #2 Member   nazareno mancinelli Join Date: Mar 2009 Location: argentina Posts: 35 Rep Power: 10 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

 April 14, 2009, 22:56 #3 Member   Join Date: Mar 2009 Posts: 35 Rep Power: 10 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.

 April 16, 2009, 15:04 #4 New Member   salman Join Date: Apr 2009 Posts: 2 Rep Power: 0 Hey tom...have you had any success yet. I am doing a similar project in 3d.

 April 16, 2009, 16:50 #5 New Member   mark Join Date: Apr 2009 Posts: 5 Rep Power: 10 Ensure axis is correct for reporting and model is scaled

 May 17, 2009, 09:58 #6 New Member   bima Join Date: May 2009 Posts: 2 Rep Power: 0 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,

 May 18, 2009, 10:59 #7 New Member   Thanh Nha Nguyen Join Date: May 2009 Posts: 3 Rep Power: 10 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!

 August 1, 2009, 02:13 #8 New Member   faddy ardian Join Date: Aug 2009 Posts: 3 Rep Power: 10 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

 August 15, 2009, 10:51 vwat #9 New Member   nassim swlyman Join Date: Aug 2009 Posts: 11 Rep Power: 10 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

March 16, 2010, 17:40
#10
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benoit paillard
Join Date: Mar 2010
Posts: 62
Rep Power: 9
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)

 April 1, 2010, 02:30 #11 New Member   SHIVA Join Date: Feb 2010 Posts: 7 Rep Power: 9 Dear Tom. Hope now u solve the Problem. i need u r help for same case. With Regards SIVA

 August 27, 2011, 01:38 Hi #12 Member   s.rasoul_varedi Join Date: Feb 2010 Posts: 82 Rep Power: 8 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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