Turbine tips tighten efficiency
Wind turbines are highly complicated instruments, required to produce a constant amount of power from an inconstant and unpredictable source. The blades of wind turbines themselves are not a simple matter, as they do not exhibit either the same performance values or the same aeroelastic stability down their lengths. Since both tower and blades reverberate at certain frequencies, it is essential that the blades do not vibrate at the same frequency as the tower. Structural dynamics such as these could result in either dampening of the bladed forces or creating resonance which could threaten the entire turbine with destruction. Additionally, monitoring and keeping blade speed at safely operable conditions requires the use of several safety features such as three types of breaking systems, various sensor technology and something called the passive tip mechanism. This mechanism controls the rotational speed of the blades, calculating wind direction and blade speed several times per second and making adjustments as and when necessary to the blade pitch and thereby inducing stall to prevent damage to the turbine. These passive tip mechanisms however are subject to frequent maintenance procedures as their continued, reliable performance is heavily relied upon to protect the turbine from critical failure. They are difficult to maintain and because of their critical value, designing a better functioning passive tip mechanism, requiring less repairing and greater resistance to fatigue is therefore of primary concern. The TENTORTUBE project initiated new investigations into carbon/epoxy composites, innovative geometric designs and flexible resin systems, in the hope that the fatigue resistance of these mechanisms can be improved. While the actual TENTORTUBE is not yet beyond the testing phase, encouraging results based on the promising material properties and aeroelastic predictions, warrant the continued testing and development of this passive tip mechanism.
