Performance improvement of vertical axis-autorotation current turbine through twin-rotors

This paper aims to study the performance for the Vertical Axis Autorotation Current Turbines through Computational Fluid Dynamics. The commercial software ANSYS®/Fluent® has been employed to determine torque coefficient and power coefficient versus tip speed ratio focusing on a particular S-shaped blade geometry (Chan et al. 2018). Verification and validation procedures were performed to ensure the feasibility of the numerical model. The Shear-Stress Transport k-ω model from Menter (1994) is the turbulence model applied to study twin-rotors in this investigation. The analysis investigates two twin-rotor configurations and compares them to a single-rotor case. If the turbines are in phase and side by side, the simulations provide an improvement on the performance about 22%. On the other hand, simulations with turbines out of phase (or with different tip speed ratio) showed that this performance can still be improved.