Testing of an arrow-head vertical-axis wind turbine model

Abstract

A vertical-axis wind turbine (VAWT) with an arrow-head rotor was tested in the laboratory at wind tunnel speeds of 16.3, 18.05 and 19.75 m/s. The power and torque coefficients were studied as functions of the blade section (rectangular and aerofoil blade sections), the blade angle θ (12, 55 and 90°), the attack angle ф (0, 30 and 90°), the blade-length ratio L/ L max (0.50, 0.75 and 1.0) and finally the tip-speed ratio U/ V. The analysis of the experimental results showed that the power and torque coefficients of the rectangular blade section were higher than those of the aerofoil blade section and they increased with a decrease in the blade angle and the blade-length ratio. They increased with an increase in the attack angle. The power coefficient increased to a maximum value and then decreased again with an increase in the tip-speed ratio, while the torque coefficient decreased directly with an increase in the tip-speed ratio. The arrow-head wind turbine performed best with the rectangular blade section with a blade angle of 12°, blade-length ratio of 0.75 and attack angle of 30°.