Numerical analysis of twist angle variations on the aerodynamic performance of NREL 5-MW wind turbine

Abstract

The study of wind turbine aerodynamics is crucial to get the best power output from the available wind flow. This thesis investigate the aerodynamics effect of twist angle variation of the blade on the power output of the turbine. The various aerodynamic parameters are also studied to understand the reasons for the changes in the power output. The well documented NREL 5-MW wind-turbine is considered in this work. Computational Fluid Dynamics (CFD) technique is used in this study. The turbine effects are implemented in the CFD model by using the Actuator Line Model (ALM). All the simulations are performed using the open-source OpenFOAM software based on the transient Reynold’s Averaged Navier Stoke (RANS) approach. In this work, in total 11 different twist angles are considered to study their respective impact on aerodynamics performance. The results reveal that certain cases in which the twist angle is less than the empirical twist angle gave better power output than the empirical power. There are 7 cases out of 11 which gave better power than the reference power. In the cases of high power, 25%-85% of the blade radius gave high lift coefficient than the reference case. The ratio of lift to drag coefficient is high for the angle of attack between 2◦-10◦.