zhenduan306 |
November 6, 2012 09:40 |
Quote:
Originally Posted by strobel
(Post 390549)
I'm sure about RPM i'm using. My reference of Cp is BEM. Im getting Cp of 0.65 at 10RPM, 2.5m/s of wind speed and my turbine has a diameter of 10m. So, in BEM i get a CP of 0.4 to theses conditions. So, something is wrong in my simulation.
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I guess your simulation has some problems. You set wind speed at 2.5m/s, if your Tip speed ratio is 7, diameter is 10m. The rotating speed is 33.44RPM, not 10RPM.
In my simulation, from cut-in speed (2.5m/s) to around 10m/s, the Cp is almost same as in BEM. But, in high wind speed such as above 12m/s, the Cp is very high. The reason is I didn't stall the rotating speed in a fix number (such as 60 RPM). I just calculate RPM according to Tip Speed Ratio and wind speed.
How is your domain? Big enough? Moreover, meshing is another issue. You'd better refine your model, if it is coarse.
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