Hello,
I think I just noticed this, but why is the NREL 5 MW hub radius so small? It’s at 1.5 m, which compares to the WindPACT 1.5 MW at 1.65 m. I don’t recall the size of “real” hub radii, but I recall standing up in many a GE 1.5 with some headroom, which makes it seem around 1.5 m radius. And GE/Enron/Tacke was known for having small hubs compared to the rest of the industry.
Hi Scott,
The 1.5-m hub radius of the NREL 5-MW turbine was chosen to be the same as that of the REpower 5M turbine; I agree that it is smaller than most hubs for turbines of that size.
This specification of a small hub radius has caused some problems – a few years back we were asked from someone developing a CFD model of the NREL 5-MW turbine why the root chord (about 3.5 m) is larger than hub diameter (3.0 m). I agree that this is not realistic. This resulted by forming the NREL 5-MW model from a composite of information from other 5-MW conceptual designs and real prototypes. It is not really a problem for most aero-elastic models, which model the rotor aerodynamics using a form of blade-element/momentum (BEM) theory (as was the purpose for making this model in the first place), which is probably why I didn’t notice this issue before publishing.
Best regards,
Thank you for the confirmation and clarification. I’ll keep modeling with the puny hub for now!