Effect of micro-cylinder as a passive controller on the Darrieus wind turbine performance

Vertical Axis Wind Turbines are more suitable for urban areas than Horizontal Axis Wind Turbines because they operate at lower wind speeds, and produce less noise, and are less expensive. In this study, the Darrieus turbine (three blades) is chosen as one of the (VAWTs) based on the NACA 0018 airfoil. The aerodynamic analyses are carried out by ANSYS Fluent software based on finite volumes method and the unsteady Reynolds averaged Navier-Stokes (URANS) equations with Shear Stress Transport (k-omega SST) turbulence model. The target of this work is to improve the performance of the Darrieus turbine by installing a micro-cylinder in various positions and various diameters. Three different micro-cylinder diameters are examined with a ratio of the micro-cylinder diameter to the chord (d/c = 0.029, 0.05, 0.065). It has been observed, the micro-cylinder improves the turbine performance in two cases: (1) The micro-cylinder diameter is smaller where the average power coefficient (CP-avg) increased by 9.5% compared to the conventional turbine at MC1 (d/c = 0.029). (2) By installing the micro -cylinder on the front of the blade leading edge where the average power coefficient (CP-avg) increased about 14.1% compared to the conventional turbine at the location (MC8). On the contrary, if the micro-cylinder diameter has lager diameter or located on the suction side or down towards the pressure side of the blade leading edge, the turbine performance decreases.