Field tests on small HAWT with passive pitch-flap mechanism

摘要

It has been already revealed the presence of high wind potential sites in the mountainous landscape of Japan. These sites are characterized by strong turbulent winds. The wind turbine blades are deduced to be acted on strong fluctuating forces in the mountainous area. The excessive output power should be suppressed and the fluctuating forces on the blade should be reduced. This paper presents the experimental data acquired from testing of two small HAWTs in a mountainous area with strong wind fluctuations. The rotors were equipped with a passive pitch-flap mechanism. The Mie-type tip vane was mounted at the blade tip. The purpose of the experiment was to verify and to validate the functionality of the pitch-flap passive mechanism in case of strong fluctuating wind conditions. The mechanism developed in this study fulfills simultaneously two functions: 1) acting as an independent passive brake for each blade, 2) acting as a damper of the fluctuating forces acting on the blades. The performance tests of the passive pitch-flap mechanism were carried out in a test site located in a complex terrain with strong turbulent wind conditions. The effect of the rotor diameter was studied and the effect of a tip-mounted Mie vane was investigated with flow visualization. The results prove that the excessive output power can be suppressed and the fluctuating forces on the blade can be reduced passively due to the passive pitch-flap mechanism.