Diseño y construcción de un prototipo de álabe para un generador horizontal de baja potencia con aplicación en zonas no interconectadas de Colombia
Thesis
This document focuses on the design and construction of a prototype blade for low-power wind turbines, as blades play a crucial role in the efficiency and performance of wind turbines. The main objective of this study is to analyze various aerodynamic profiles and optimize the blade design to maximize energy extraction by improving the lift-to-drag ratio. One of the challenges addressed in this study is the problem of boundary layer separation that affects low-power horizontal-axis wind turbines available in the market. Through the analysis of aerodynamic performance coefficients and modeling in specialized software, an optimal blade profile was developed that minimizes separation issues and maximizes power generation. This study aims to contribute to the advancement of wind technology in non-interconnected areas of Colombia, where the lack of coverage by the conventional electrical grid has driven the search for autonomous and sustainable energy solutions. The implementation of low-power wind turbines with optimized blades could offer a viable alternative to meet the energy needs of these communities. In this research work, a comprehensive review of relevant literature references was conducted, and performance criteria were established for the selection of airfoil profiles. Profiles such as Wortmann FX60-126, SG6043, SG6042, NACA 4415, NACA 0018, AF300, NACA 4412, and CLARK Y were identified, demonstrating outstanding performance in terms of aerodynamic efficiency, lift generation, and low drag. These profiles were modeled in XFOIL/XFLR5 software, where different parameters such as Reynolds number, angle of attack, number of profile panels, meshing, and extrusion were evaluated. The obtained results allowed for the selection of two optimal profiles (SG6043 20% / GOE300 80%) and the creation of a mixed profile named UR001 using the Interpolate Foils module. This new profile was further optimized using the XFOIL Inverse Design module. For the new UR001 airfoil profile, the lift coefficient Cl becomes positive for a negative angle of attack α of -3° and increases linearly with a constant slope up to α = 7°, reaching Cl = 1.4 (Cl increases by 0.14 for each degree increase in the angle of attack). Then, this slope decreases in the range of α between 7° and 15° and eventually decreases (Cl increases from 1.4 to 1.6 in 8°, with an increase of 0.025 per degree). This profile is determined as optimal for the construction of the low-power wind turbine prototype, and it is 3D printed. Based on the results obtained with the airfoil profiles, (angle of attack = 7°, Cl/Cd = 56.293, Clmax = 1.6253), the power coefficient Cpot was calculated for a 3-blade type wind turbine, with tip speed ratio λ = 3, rotor radius R = 1 meter, assuming an average wind speed = 5 m/s. For these conditions, Cpot = 0.533 was obtained, which gives us a nominal power of 125W. This covers 50% of the energy requirements for an average ZNI home, defined as 208W. The blades were designed with a length of 1 meter, divided into 18 sections with chord sizes that vary between 22 and 38 cm, and torsion angles, between 12.3° and 43.8°. Finally, a simulation in SolidWorks CFD is performed to study the profile's behavior when exposed to wind (5 m/s). A comparison with the data obtained in XFLR5 shows a high similarity, allowing us to infer that the initially obtained results in XFLR5 are consistent with the modeled behavior.
