# Wind Turbine Simulation

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 April 2, 2016, 16:27 Wind Turbine Simulation #1 New Member   Hammad Iftikhar Join Date: Nov 2015 Posts: 7 Rep Power: 2 Hi, I am working on wind turbine simulation using a rotating reference frame. My aim is to calculate the power generated by the designed turbine. Here is what I have so far. I have created a fluid domain with the rotor in the middle and a cylinder to simulate the rotating domain. Right now the rotor is subtracted from the domain while the cylinder is whole. My first question is whether it is fine the way I have it currently configured or should it be some other combination? Should I subtract the cylinder from the fluid domain and then the rotor from the cylinder? Any help would be appreciated, Thank You.

 April 3, 2016, 08:22 #2 Senior Member   Cees Haringa Join Date: May 2013 Location: Delft Posts: 437 Rep Power: 9 Looks fine, you can indeed subtract the rotor from the cylinder. The cylinder and bulk domain should be separate bodies that do not overlap; is that currently the case?

April 3, 2016, 12:16
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Join Date: Nov 2015
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Quote:
 Originally Posted by CeesH Looks fine, you can indeed subtract the rotor from the cylinder. The cylinder and bulk domain should be separate bodies that do not overlap; is that currently the case?
Currently they overlap as I wasn't sure. I will fix that.

Furthermore as I understand to calculate power I will multiply the rotational velocity given to the moving frame with the torque that is felt on the rotor. Is that correct?

 April 3, 2016, 14:25 #4 Senior Member   Cees Haringa Join Date: May 2013 Location: Delft Posts: 437 Rep Power: 9 Ok, if you subtract the cylinder from the box, and keep the cylindrical body with the rotor, all should be fine. You can calculate the torque using reports > forces and then select moments, setting the right axis origin and direction, and then calculate the torque on the turbine indeed. After that, indeed multiply by the 2*pi*N (rps), and you have the power. Good luck! Cees

 April 4, 2016, 12:15 #5 New Member   Hammad Iftikhar Join Date: Nov 2015 Posts: 7 Rep Power: 2 Just an update. I made the mesh shown below, used sphere of influence in body sizing so that most of the elements are in the middle. I feel that the elements might not enough but considering the computer I have access to currently this is the best I can do. I hope to make a finer mesh once I have access to a more powerful computer. In fluent I set the time to transient, k-w SST for turbulence, frame motion to the cylinder about x-axis at 37.5 rad/s. Inlet velocity set to 5 m/s and pressure outlet. Set the flow time to 5s with 50 intervals each 0.1s. The solution is being calculated as we speak. Hope it works out.

 April 4, 2016, 12:33 #6 Senior Member   Cees Haringa Join Date: May 2013 Location: Delft Posts: 437 Rep Power: 9 why is there a very dense mesh region far away from the cylinder? I understand you are limited in the mesh size, so it seems to me it is important to be efficient in refinement - that clump of cells on the upper right does not look very efficient to me. Maybe you can improve the mesh, making sure: 1) the mesh is fine close the the blades, and cruder far away 2) the domain is predominantly filled with hexahedral/polyhedral elements (hexahedral will be though/impossible near the impeller, but surely applicable to the bulk of the domain)

 April 7, 2016, 08:33 #7 New Member   Hammad Iftikhar Join Date: Nov 2015 Posts: 7 Rep Power: 2 I changed the mesh to be a bit more concentrated around the cylinder. A view of the new mesh Sliced View Along the XZ Plane Sliced View Along the YZ Plane Afterwards I ran the calculations and it came with the following moment report. But according to this the turbine would generate only 0.090707897*37.5 = 3.40 W Power available = 0.5*3.1415*(0.4^2)*(5^3)*1.225 ( 1/2 * pi * r^2 * v^3 * rho) = 38.48 Which would correspond to a coefficient of performance of 8.839% which seems quite low. Is this right considering the blade shape and the small size and speed or am I doing something wrong?

 April 7, 2016, 16:41 #8 New Member   Hammad Iftikhar Join Date: Nov 2015 Posts: 7 Rep Power: 2 Looking at the results in CFD-Post I think I might have screwed up the mesh interfacing. I am going to try again this time interfacing each face individually.

 Tags fluent, power, wind turbine

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