Power Enhancement of a Vertical Axis Wind Turbine Equipped with an Improved Duct

Abstract

Efforts to increase the power output of wind turbines include Diffuser Augmented Wind Turbines (DAWT) or a shroud for the rotor of a wind turbine. The selected duct has three main components: a nozzle, a diffuser, and a flange. The combined effect of these components results in enriched upstream velocity for the rotor installed in the throat of the duct. To obtain the maximum velocity in the throat of the duct, the optimum angles of the three parts have been analyzed. A code was developed to allow all the numerical steps including changing the geometries, generating the meshes, and setting up the numerical solver simultaneously. Finally, the optimum geometry of the duct has been established that allows a doubling of the flow velocity. The flow characteristics inside the duct have also been analyzed in detail. An H-Darrieus Vertical Axis Wind Turbine (VAWT) has been simulated inside the optimized duct. The results show that the power coefficient of the DAWT can be enhanced up to 2.9 times. Deep dynamic stall phenomena are captured perfectly. The duct advances the leading-edge vortex generation and delays the vortex separation.

Power augmentation of ducted wind turbines for urban structures: Experimental, numerical, and economic approaches

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Rotary Wing Aerodynamics

“…The fourth article collected in this Special Issue by Ranjbar et al [5] turns readers back to the investigation of wind turbine aerodynamics. In particular, the article is focused on the aerodynamic performance optimisation of a quite interesting machine in the wind energy field, i.e., a vertical-axis-ducted wind turbine.…”

“…Three articles deal with rotorcraft aerodynamics applications, i.e., two numerical studies on innovative rotorcraft configurations such as eVTOL aircraft [1] and tiltrotors [2] and an experimentalnumerical study aiming to study the fine wake details of a helicopter's main rotor [3]. Two articles deal with wind turbine aerodynamics applications, i.e., an experimental activity aimed to develop both aerodynamic and structural strategies to design an experimental model of a wind turbine rotor [4] and a numerical study aiming at the duct optimisation of a vertical-axis wind turbine finalised to power enhancement [5]. The last article describes a trade-off activity between rotorcraft and wind energy research fields, showing the results of piloted simulations to determine possible risks associated to wind turbine interactions in rotorcraft operations [6].…”