Enhancing Performance of Small Capacity Horizontal Axis Wind Turbine Using Grooved Linearized-Chord Blades

Abstract

In the current article, E216 airfoil blades with linearized chord of a small-scale horizontal axis wind turbine are numerically investigated to enhance the performance of the turbine. The blade is modified by including grooves on its suction side. Three-dimensional Reynold’s averaged Navier–Stokes (RANS) simulations are performed with Shear Stress Transport k–ω as a turbulence model. The computed power-coefficient results are first validated with previous measurements by the present authors on a wind turbine of 1 m rotor diameter at two wind speeds of 6 and 8 m/s. Another validation with measurements from the literature is performed via comparison of the pressure-coefficient distribution along surfaces of E216 airfoil at an angle of attack of 6 deg. Based on the successful computation, six different rotor models are numerically investigated with different numbers and locations of grooves created along the blade length, from the hub to the tip region, on the blade suction side. The lift and drag coefficients are compared for the different simulated rotor models. Furthermore, the torque coefficient, thrust coefficient, and static torque coefficient are obtained for the simulated models. It is found that the best-simulated configuration is Model 1 having one groove at 80% blade-chord length from the leading edge, with a maximum power coefficient of 0.429 at a tip-speed ratio of 4.75. The aerodynamic performance of the blades is strongly affected by the groove on the suction surface. The results show that Model 1 blade reduces the generated mean-axial force and its vibration frequency on the rotor.