Abstract
A wind turbine has been developed to a more sophisticated design that take account of many design factors. For example, the effect of wind velocity fluctuation at the installation site is considered to obtain larger wind power from unsteady wind than one from steady wind. This paper describes the performance evaluation of horizontal axis wind turbine in low turbulent intensity natural wind using an original low-cost multi-fan active control turbulence wind tunnel. In particular, this research focuses on the effects of integral scale of turbulence and blade type on wind turbine performance. The performances of original NACA and MEL wind turbine rotors are evaluated in the natural wind of mean velocity 7 m/s, turbulent intensity 2% with varying integral scale 5 m, 10 m and 20 m. As the results, the power coefficient of the MEL rotor in the natural wind with integral scale 20 m is about 1.1 (110%) times as large as one in steady wind. Furthermore, integral scale has larger effect on the MEL rotor than NACA. In addition, we show the Large Eddy Simulation (LES) results of the flow field around the NACA and MEL wind turbine rotors in steady wind of mean velocity 7 m/s and 1800 min-1 (tip speed ratio equals to 2.6) using the commercial software ANSYS CFX.
