Design, development and multi-disciplinary investigations of aerodynamic, structural, energy and exergy factors on 1 kW horizontal-axis wind turbine

Abstract

AbstractContinually increasing demand for energy, coupled with the need for clean environment, has made it mandatory to fall back on efficient conversion of energy from renewable sources. Wind energy is one of the most viable sources of renewable energy. A wind turbine blade, shaped as an airfoil with a streamlined cross-section, can be graded for its aerodynamic efficiency in terms of lift-to-drag ratio. Optimal design and analysis of blades with different airfoil sections is critical for efficient energy extraction. In this paper, computational fluid dynamics (CFD) is used to predict the aerodynamic efficiency of wind turbine blades. To set the basics right, a detailed review of aerodynamics of the 2D airfoils are undertaken: (a) NACA4412, (b) NACA23012 and (c) NACA63215 airfoils. Additionally, a numerical study on structural analysis for a 1-kW horizontal-axis wind turbine blade using finite element analysis (FEA) to assess the initial failure of NACA 63215 airfoil internal structure after optimization was conducted. In the internal structure of the blade, a single spar was included to make the structure more efficient in bending. Structural optimization resulted in bringing the weight down from an initial weight of 5.6 kg to a final design weight of 1.1 kg, i.e. a net saving of more than 4 kg. In addition stress levels in the model also improved with the failure indices turning toward unity. Optimized structural thicknesses in terms of glass fiber-reinforced plastic (GFRP) layers were found within safe limits. From FEA study and based on the von Mises stress distribution on the pressure and suction sides of wind turbine blade from root to tip, the initial failure was found to occur in the overlap edge of root region when the equivalent stress reached to the ultimate stress of the tip region. It was found that a well-designed GFRPs wind turbine blade is very efficient compared with metals/alloys.