Comparative Study of the Effect of Chord Length Computation Methods in Design of Wind Turbine Blade

Abstract

Design of wind turbine blade is the most important step in developing efficient non-conventional energy converters in order to tackle today’s energy crisis scenario. In horizontal axis wind turbines in particular, blades are the most important parts of the turbine and needs optimized design since it has direct relation with output performance. In addition, the turbine blade is critical part in terms of the manufacturing cost of the blade, which is about 15–20% of the total wind turbine plant cost. One of the main design parameters in the geometry of wind turbine blades is the cord length. This parameter affects not only the performance, but also the blade structural stiffness. Closer review of the literature shows that there is no commonly accepted formula for calculation of chord length distribution. Thus, this paper focuses on comparative study of the works of different researchers on the formulas used for calculation of chord length distribution along the blade. Upon evaluating the available formulas, some methods of combining works of different researchers for designing horizontal axis wind turbine blade are included such as chord length distribution, manufacturing complexity of wind blade, weight of the blade and power output obtained. Each method is compared for the same airfoil, input parameters like radius, wind speeds, number of blades, tip speed ratio and materials. Effect of the chord length of the blade on the performance of the wind turbine is computed a dedicated software (Qblade) and analyzed.