Aerodynamics Analysis of Small Horizontal Axis Wind Turbine Blades by Using 2D and 3D CFD Modelling

Abstract

Please write a brief description of your work, or copy an abstract you have included in the Thesis Wind power is one of the most important sources of renewable energy. Wind-turbines extract kinetic energy from the wind. Currently much research has concentrated on improving the aerodynamic performance of wind turbine blade through wind tunnel testing and theoretical studies. These efforts are much time consuming and need expensive laboratory resources. However, wind turbine simulation through Computational Fluid Dynamics (CFD) software offers inexpensive solutions to aerodynamic blade analysis problem. In this study, two-dimensional aerofoil (i.e. DU-93 and NREL-S809) CFD models are presented using ANSYS-FLUENT software. Using the Spalart-Allmaras turbulent viscosity, the dimensionless lift, drag and pitching moment coefficients were calculated for wind-turbine blade at different angles of attack. These CFD model values we then validated using published calibrated lift and drag coefficients evident in the literature. Optimum values of these coefficients as well as a critical angle were found from polar curves of lift, drag and moment modelling data. These data were exploited in order to select the aerofoil with best aerodynamic performance for basis of a three-decisional model analogue. Thereafter a three-dimensional CFD model of small horizontal axis wind-turbine was produced. The numerical solution was carried out by simultaneously solving the three-dimensional continuity, momentum and the Naveir-Stokes equations in a rotating reference frame using a standard non-linear k-ω solver so that the rotational effect can be studied. These three-dimensional models were used for predicting the performance of a small horizontal axis wind turbine. Moreover, the analysis of wake effect and aerodynamic noise can be carried out when the rotational effect was simulated.