Computational Investigation of Cavitation n Horizontal Axis Tidal Turbines Blades

Douvi C. Eleni, Margaris P. Dionissios

This study will focus on the possibility of cavitation on various tidal turbine blades, constructed from four different airfoils, in particular a symmetrical airfoil, NACA 0024, and three cambered airfoils, Göttingen 770, NACA 4418 and NACA 4424. The optimum geometry of each rotor, in other words the chord length and the twist along the blade, is calculated by a user-friendly application based on the Blade Element Momentum method. This user-friendly application can also predict the power coefficient and the power output for tidal turbine rotors by examining different parameters, such as the hydrofoil profile for the blades, the number of blades, the tip speed ratio, the tidal current velocity and the rotor diameter. The flow over the optimum geometries was simulated by a commercial Computational Fluid Dynamics code for two different depths, three different blade lengths and at various tip speed ratios, in order to determine whether it is possible to occur cavitation under these operating conditions. The blade which experienced the less intense cavitation occurrence was the NACA 0024 blade.

https://doi.org/10.31871/IJNTR.3.12.68