Investigation of the effect of critical structural parameters on the aerodynamic performance of the double darrieus vertical axis wind turbine

Double Darrieus Vertical Axis Wind Turbine (DD-VAWT) can efficiently capture wind energy at low tip speed ratios. In this work, the laws governing the effects of critical structural parameters, such as diameter of inner ring wind turbine, height of inner ring wind turbine, inner ring wind turbine blade airfoil chord length, and phase angle of inner and outer ring wind turbine, on the power performance and aerodynamic load are investigated. The power coefficient increases from 0.1670 to 0.2403 when the diameter of the inner ring wind turbine decreases from 1600 mm to 400 mm. The power coefficient increases from 0.1755 to 0.2135 when the height of the inner ring wind turbine increases from 600 mm to 1200 mm. The power coefficient increases from 0.1773 to 0.2135 when the chord length of the inner ring wind turbine blade airfoils increases from 0.15 m to 0.3 m. The power coefficient decreases from 0.2135 to 0.1976 when the phase angle of the inner and outer wind turbine is increased from 0° to 135°. Finally, based on Taguchi's experiments and grey correlation analysis, it is known that the most influential weight on the power coefficient and the maximum instantaneous torque coefficient is the airfoil chord length of the inner ring wind turbine blades, and the least is the phase angle of the inner and outer ring wind turbines. This work provides a reference for enhancing the DD-VAWT's performance.