Aerodynamic shape optimization and analysis of small wind turbine blades employing the Viterna approach for post-stall region

Abstract

This paper aims to optimize the distribution of chord and twist angle of small wind turbine blade in order to maximize its Annual Energy Production (AEP). A horizontal-axis wind turbine (HAWT) blade is optimized using a calculation code based on the Blade Element Momentum (BEM) theory. A difficult task in the implementation of the BEM theory is the correct representation of the lift and drag coefficients at post-stall regime. In this research, the method based on the Viterna equations was used for extrapolating airfoil data into the post-stall regime and the results were compared with various mathematical models. Results showed the high capability of this method to predict the performance of wind turbines. Evaluation of the efficiency of wind turbine blade designed with the proposed model shows that the optimum design parameters gave rise to an increase of 8.51% in the AEP rate as compared with the corresponding manufactured operating parameters.