Critical Design Parameters Affecting the Performance of Small Wind Turbine Blades at Low Wind Speeds: A Review

Abstract

The aerodynamic efficiency of a wind turbine relates to the ability of the rotor to transform kinetic energy in the wind to mechanical energy. Some of the parameters interacting in this process are air density, rotor swept area, blade geometry, airfoil configuration, and the wind velocity. Of these, blade design is a prevailing factor as it dictates the forces acting in the air that produce torque and the forces that extract energy. This paper presents a review of the main design variables influencing the power coefficient and the overall output of horizontal-axis wind turbines. Special attention is paid to the effect of tip speed ratio and blade pitch angle on aerodynamic performance. The literature suggests that the optimal rotor efficiency is reached within the range of tip speed ratio (4-7) and the pitch angle (0^o - 3^o). The effectiveness of the turbine in converting energy is greatly improved by the optimization of these parameters.