The flat trailing blade edge is one innovation from Sandia. The flat surface allows a more rigid blade (less twist) with little performance loss. The grey fins are to break up the vorticies generated by the surface to quiet its performance.
In preparation for the Sandia Wind Turbine Blade Workshop, Sandia structural engineer Todd Griffiths sat down with me for a preview of his presentation and others. He tells of four important areas for Sandia’s wind effort. One is the active or smart blade, a blade that can react to changing wind conditions. As you can imagine, the wind at the top of the rotor sweep can differ from the wind at the bottom in speed and direction. A blade with active surfaces could make adjustments that would not need a pitch change and hence, lighten the torsional loads to the gearbox and generator. A second area is a test center in Lubbock, Texas that will examine the effects of rotor wakes on downwind turbines. Another area is the quest for the 100-m blade. Can one be made to last 20 years? If so, it could vastly improve energy capture for 10 MW (my guess) turbines. And lastly, return of the vertical axis wind turbine. For large turbines, in the 10 MW and more range, a VAWT might make more sense. It would need a much shorter tower and putting all mechanicals at the base makes sense as the wind industry struggles with an apparent 10-MW limit to conventional turbines.
A tour of some of the Sandia facilities, arranged for me by pr staffer Stephanie Holinka, was conducted by Dr. Jonathan White, Sensing Technologies and Testing Lead Wind Energy Technologies. The goal of the lab, says White, is to tackle big problems that universities or companies could not afford, and follow it through from a feasibility study, to simulation, construction, and test, and then disseminate a report on it. The Smart Blade or one with active surfaces, is one such program. The program is about half way through with a set of smart blades spinning at a Texas test facility.
Blade research consumes a good part of the wind lab with experiments with new materials and sensors. White says that before a new blade is ready to fly, the lab invites strain-gage companies to put their products on the blade for tests.
A recent endeavor of the lab is to collect and analyze SCADA data from about 2% of the U.S. fleet of turbines. The Lab will look for maintenance and performance trends among equally sized turbines and report on which farms and size of turbines are performing well and which are less so. “However, we don’t want the program to make us the Consumer Reports of wind turbines,” says White. The reference is to the magazine that rates the perceived quality of consumer goods.
The Blade Workshop starts tomorrow with three days of what appear three days of stimulating discussions. Watch our Twitter feed, @Windpower_Eng for updates from the presentations.
–Paul Dvorak
Editor, Windpower Engineering & Development
Filed Under: Blades, News
