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 (SSHAWT) are numerically investigated to enhance the performance of the turbine. The blade is modified by including grooves on its suction side. Three-dimensional RANS simulations are performed with Shear Stress Transport (SST) 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°. 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 maximum power coefficient 0.429 at 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.

Improving performance of H-Type NACA 0021 Darrieus rotor using leading-edge stationary/rotating microcylinders: Numerical studies

“…Furthermore, the sliding-mesh technique was employed to simulate the rotational motion of the wind turbine rotor, see El-Askary et al [8].…”

“…2. Interface boundary condition was used to merge the separated zones, for more details see El-Askary et al [8]. The inlet plane of the computational domain was placed at 10 rotor diameters, while the outlet plane was placed at 25 rotor diameters downstream, and the side boundaries were set at 10 rotor diameters.…”

“…However, the calculated power coefficient (Cp) using the SST k-ω turbulence models shows a reasonable agreement with the measurement over most turbine TSR. The SST k-ω turbulence model is then used to close the RANS equations in all coming computations, as recommended by El-Askary et al [8] and Rezaeiha et al [34], who studied the same rotor profile. Therefore, all the coming calculations were performed using the SST k-ω model.…”

“…Therefore, passive flow control techniques are the most effective ways to control the flow separation on the small-scale wind turbine, thus improving its aerodynamic performance. Some of these passive techniques have been implemented in the last few years such as vortilons, flow vanes, gurney flaps, fixed leading edge slats, aerofoils with protuberances, cavities, passages, slots and microcylinder [8]- [11].…”