Wind tunnel investigation of blade pitch effect for performance improvement of an asymmetric bladed H-Darrieus VAWT under low wind speed condition

Abstract

In this paper experimental investigation is conducted to analyse the blade pitch effect on the performance improvement (self-starting and dynamic performance) of a NACA 63415 asymmetric bladed H-Darrieus VAWT at low wind speed conditions (5.0 and 6.0 m/s). It has been found that the performance of the considered VAWT has improved with a change of blade pitch angle (β) from negative to positive value. A maximum power coefficient (Cp) of 0.086 is obtained at a tip speed ratio (TSR) of 1.73 at a wind speed of 6.0 m/s for β = + 5°. Further turbulence intensity (TI) and flow non-uniformity (NU) are also calculated. In this case, TI of 2.6% and 2.4% is calculated from experimentation along with 4% and 3.33% non-uniformity (NU) for wind speeds 5.0 and 6.0 m/s, respectively, which are responsible for Cp improvement.