Wind Empowerment
Hi all,
hope all is well !
Thought I share this development from Big Wind.
It is quite known that the root of the blade needs to be strong and the more out you go to the tip, the shape of the blade plays a bigger role in energy capture.
However - something also our aero team (accidentally :) ) found out is that when you have large cords at the root the inner center part of the rotor will block the wind and that will influence the wind flows in a positive manner at the outer radial part of the rotor - where the energy capture happens.
(GE now knows and I guess Enercon has known already for a long time looking at their blade root designs)
I guess your design might also have this positive effect with the relative large radial generator compared with other designs .Maybe try even a larger radial generator designs - or time to make funny noses for small wind? Something to contemplate about.
best, Piet
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GE plans to nose ahead
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08/06/2015
GE has started testing its ecoROTR turbine, which includes a large spinning silver aluminium dome bolted to its rotor.
The company said if the experiments confirm wind tunnel data, the 20,000-pound dome (pictured) could lead to larger and more efficient turbines for windy locations that are currently too hard to reach for the industry.
The project aims to tackle two problems with wind turbines: first, they “waste” too much wind and aren’t as efficient as they could be.
Second, the blades and towers are so big and heavy, they are hard to transport to the remote places where the wind is best.
The project started with a Styrofoam ball and a toothpick two years ago, when Mark Little, who runs GE Global Research, challenged his scientists to build a rotor that could harvest more wind.
GE Global Research leader of sustainable energy Mike Bowman said: “The design looked really strange, but it made a lot of sense.
“When wind hits the center of the wind turbine where the blades are attached, it’s wasted. That’s because the blades are basically levers and the same wind generates more force further from the hub.”
Bowman’s team thought that if they deflected the wasted wind from the hub, the blade tips could harvest its power. The nose could also allow them to build bigger rotors without lengthening the blades, since they could attach them to its perimeter.
“When we crunched the numbers, we saw up to a 3% increase in performance,” Bowman said. “It doesn’t seem like much, but it’s potentially a lot when you apply the savings across an entire wind farm with dozens of turbines.”
The next step was to design a life-like ten-foot version of the turbine, which they took to the University of Stuttgart in Germany for more hard-core testing.
Back in the USA, they used the test results to further validate the design of the full-scale version of the ecoROTR, which is now spinning in Tehachapi.
The team attached the experimental dome, which is 60 feet in diameter, to a 1.7MW wind turbine, on top of a 300-foot tower.
Like the dome, the tower is also a prototype. Instead of traditional steel tubes, its “space-frame” design uses metal latticework wrapped in a polyester weave coat. The girders can be loaded inside shipping containers and onto ordinary trucks, and bolted together in places that were previously hard to reach.
The sensors are everywhere, starting on the tower legs at the ground level, up to the turbine’s spinning shaft. The team regularly pores over the data, looking for signs that the experiment is working or needs to be tweaked. This phase of the project will last another four months.