Wind Turbine Blades with a Twist Could Boost Performance
- Dec 14, 2018 2:25 pm GMT
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Three innovative 20 meter long rotor blades with a novel bend-twist coupling will be tested over the next four months at the National Wind Technology Center in Colorado. The tests are part of an effort to learn how effective the blades are at dampening peak loads during strongly variable wind speeds.
Rotor blades equipped with bend-twist coupling can adapt by themselves to variable wind conditions. In particular, as wind speed increases the blades can bend or twist. Doing this presents a smaller blade impact surface to the force of the winds.
Developers of the twisting blade say that the smaller surface is intended to reduce the overall load on the system, potentially increasing the wind turbine's life and its power yield.
The blades were developed as part of the SmartBlades2 project, and were designed by the Fraunhofer Institute for Wind Energy Systems and built by the German Aerospace Center. They will be tested at the wind technology center, which is part of the National Renewable Energy Laboratory.
Systems will continuously control how the blades behave under a wide range of wind loading conditions the turbine will test. The turbine’s tower and the nacelle, made available by NREL, are also equipped with measuring technology, enabling the team to measure the whole system’s behavior in detail.
Measurements will be correlated with data on wind conditions, which will be recorded by NREL data acquisition systems and a Spinner lidar (light detection and ranging) measurement device. This lidar is normally installed in the spinner of a wind turbine. For the NREL tests, the device will rest on top of the nacelle to analyze the wind field both in front of and behind the turbine.
Researchers say that comparing the structural behavior measured by the sensors with the wind data will show whether the rotor blades achieve the desired behavior.
Wind conditions at the test site at the edge of the Rocky Mountains near Denver can range from very low speeds to powerful gusts in winter and early spring. This will make it possible for the researchers to assess the rotor blades under a variety of environmental conditions.
Design validation will start with data analysis while measurements are still being conducted, and will continue until the autumn of 2019. The project is intended to help support the wind energy industry in developing rotor blades with bend-twist coupling and may pave the way to implement this technology.
The SmartBlades2 project is funded by the German Federal Ministry for Economic Affairs and Energy and is being carried out by the Research Alliance Wind Energy, with partners DLR, Fraunhofer IWES and ForWind. Industry partners include GE, Henkel, Nordex Acciona, SSB Wind Systems, Suzlon, Senvion and WRD Wobben Research and Development.