Optimizing of horizontal axis wind turbine blades using MATLAB-based blade element momentum theory with validation in QBlade and CFD software

Abstract

This study presents the optimization of a small horizontal axis wind turbine blade at a low wind speed of 6 m/s. A MATLAB code employing Blade Element Momentum Theory (BEMT) was developed to optimize the chord length and twist angle. The optimized design was further analyzed and validated using QBlade software and ANSYS^® 2022R1. The study considered two airfoils SG6041 and NACA4711 under Reynolds numbers of 1,000,000 and 100,000, respectively. The blades SG6041 and NACA4711 were divided into 10 and 20 segments for detailed analysis, resulting in power coefficients of 0.455 for SG6041 and 0.521 for NACA4711. The consistent results across MATLAB, QBlade, and ANSYS confirm the accuracy of the BEMT-based optimization process. The rotor achieved optimal performance at Tip speed ratios of 8.5 for SG6041 and 7.5 for NACA4711. Results demonstrated a high correlation between the power coefficients for QBlade and CFD simulations, with only a 1% variation for NACA4711 and 1.78% for SG6041. This study highlights a systematic approach for small wind turbine blade optimization, particularly at low wind speeds. Hence, it can be deemed that this approach is among the most crucial techniques for constructing and optimizing the blades and rotors of micro-wind turbines.