Three-dimensional CFD analysis of performance of small-scale hawt based on modified NACA-4415 airfoil

Abstract

The geometric of a wind turbine rotor is an important parameter in the development of a horizontal axis wind turbine (HAWT). Simulation can be used to determine the rotor's optimum geometry for specific wind speeds. The present study describes the three-dimensional (3D) computational fluid dynamics (CFD) simulation of a modified small-scale NACA-4415 HAWT rotor in order to predict power output and coefficient, using Blade Element Momentum (BEM) based on Lifting Line Theory (LLT). Power output and coefficient were analysed at wind speeds of 3, 4, 5, 6, and 7 m/s. The results predict that maximum power output increases with increasing wind speed. The predicted minimum power output of 35.41 Watt was obtained at wind speed 3 m/s and Tip Speed Ratio (TSR) 4; the predicted maximum power output was achieved at wind speed 7 m/s and TSR 6. As in the case of power output, power coefficient also improved with rising wind speed, with a coefficient of 0.259 at wind speed 3 m/s and TSR 4 and a coefficient of 0.449 at wind speed 7 m/s and TSR 5. Given Indonesia's typical wind speed of 4 to 5 m/s, this modified NACA-4415 rotor is predicted to generate between 92 and 255 Watts of power. The power output results show good agreement between simulation and experiment, with an R2 value of 0.93.