Rotating-Boom Facility for Evaluation of Wind Characteristics Approaching a Wind-Turbine Blade

摘要

A rotating-boom apparatus has been developed to test transient anemometer measurements on rotating systems. The apparatus consists of a counter-balanced helicopter blade mounted vertically at the top of a walk-up scaffold. The blade is rotated by a variable speed, one-half horsepower electric motor. The system is designed to operate over a range of rotation speeds, from less than 10 to approximately 100 revolutions per minute. Either hot-wire or hot-film anemometers can be mounted at the tip of the blade. The anemometers will sense both the normal and vertical wind components aproaching the blade. Two battery-powered, constant temperature anemometers can be mounted to the counterbalance side of the boom. The output of the anemometers is taken off the rotating shaft by a series of slip rings. Techniques for measuring the normal and vertical time-dependent wind velocities approaching a rotating wind turbine blade are also considered. While the split film type sensor has proven of value in evaluating the two components of turbulence, it may be difficult to apply in the wind turbine case. Since the anemometer electronics must ride on the rotating blade, battery-powered circuits are preferred. The battery-powered circuits are limited in power required to operate the film sensors. Alternative techniques using split hot-wire sensors are presented for application to measurements on wind turbine blades. Preliminary evaluation of data taken using hot-wire sensors shows that this would be a valuable tool in understanding wind characteristics seen by a wind turbine blade. (ERA citation 08:035711)