Studies on Dynamics of Wind Turbine Rotor Blade System

Abstract

The use of wind turbines offers a pollution-free, sustainable, and economically workable alternative to the provision of energy. Though substantial progress has already been made in the area of the wind industry, the performances of small wind harvesters can still be enhanced. It is essential to conduct additional research on the aerodynamics of wind turbines and their interaction with fluid flow. It is thus necessary to know various methods that can enhance the potential of a wind turbine. Over the last three decades, the size of the wind turbine blades has increased significantly. This growing size along with the associated mechanical behaviour, results in the generation of aeroelastic effects caused by the fluid-structure interaction (FSI). Effective FSI modelling of rotor blades is highly essential for the research of large-scale wind turbines. These large-scale wind turbines, on the other hand, are incapable of powering small devices, especially in remote locations where such small devices are used to monitor temperature, traffic, cyber security, etc. A small-scale energy harvester that can be used effectively in low-power devices must be investigated. Accommodating the aforementioned statements, this research work has implemented a numerical technique to enhance wind turbine output using different modifications and configurations. The fluid-structure interaction (FSI) analysis is also performed for wind turbine blades using composite materials. Furthermore, an attempt has been made to examine the functioning of a small lab-scaled wind turbine experimentally inside the wind tunnel. To execute these techniques, the fluent solver has been used with the help of the finite-volume method. In this work, four different types of airfoils were investigated, i.e., NREL (National Renewable Energy Laboratory) S809, S818, S825, and S826. Moreover, this work covers two configurations of a wind turbine: one the two-bladed turbine and the other the three-bladed turbine. For the two-bladed turbine NREL phase VI model has been considered to carry out the numerical investigation. For a three-bladed turbine, three kinds of the turbine have been designed and are listed below. 1) Design of the turbine by changing the two-bladed NREL phase VI to the three-bladed turbine. 2) Design of the turbine by using the dimension of GE 1.5 MW and considering S818 airfoil, S825 airfoil, and S826 airfoil. 3) Design of in-house laboratory-scale wind turbine by considering S818 airfoil, S825 airfoil, and S826 airfoil. An FSI simulation was performed for a blade by taking four composite materials in turns. CFD is used to compute the aerodynamic loads, whereas FEA is used to determine the blade structural reactions. The investigation was conducted using commercially available ANSYS packages. The performance of the turbine has been studied in terms of power, torque, deformation, and Von-Mises stress under varying conditions, and the most efficient conditions are outlined. Experiments on small-sized wind turbines have been executed inside the subsonic wind tunnel. Performance parameters are checked by varying wind speeds and loads. An electromechanical model has been developed. The results of the experiments have been compared with the electromechanical model. The experimental outcomes indicate that the designed wind turbine is capable of powering micro-devices.