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Realistic size limitations on small VAWTs
Evening all, fantastic software QBlade team.
Realistically what is the smallest you can make a VAWT while still generating meaningful power and not having unrealistic RPMs? In my mind it cant be smaller then 4m D, 4m H.
Is there any rule of thumb agreement on this? Or any papers that address this?
Also is there anywhere I can download MultiRePolar.plr for NACA foils (0012 to 0024 etc), I have the “NACA_0021_MultiRePolar.plr” from the Sandia34m project and I find my own 360 Polars don’t look as good when I extrapolate.
Thanks in advance.
Hi,
I think that hard to answer because I dont know what “meaningful” means. Pretty much depends on the requirements. With a very small VAWT you could for example recharge small batterie packs, but for household consumption the swept area should probably be in the ballpark of 1 m^2.
Ragrding the polars: you should try playing around with the parameters during the extrapolation of the polar data. It is always possible to generate smooth curves if the parameters are chosen correctly. Use the Montgomery extrapolation and try to attach to your original polar curve where it is still continuous and doesnt have discontinuities.
Regarding polar data, you can find some data on this site: http://airfoiltools.com/airfoil/details?airfoil=n0012-il
BR,
David
