Geometry and Structural Design of Tidal Current Turbine

Tidal energy is an attractive source of renewable energy since it is regular and predictable. Due to this fact, various types of tidal turbines have been developed to explore renewable energy technology. In this study, a tidal current turbine is designed using hydrofoil NACA 63-424 for 5 m long blades to extract 200 kW. Using the blade element-momentum theory (BEMT), the blade geometry was optimized such that the turbine demonstrates a maximum power coefficient at a tip speed ratio (TSR) of 4.5. We also analyzed pitch control for the turbine to maintain consistent power generation at various inflow velocities. With the current blade design, we computed forces and moments acting on the blades by applying the BEMT to design stiffness of the blade structure. In order to reduce the risk of cavitation at the design stage, we also conducted cavitation analysis using the pressure coefficients computed by ANSYSFluent. The analysis showed that the blade will not experience cavitation. Finally, we could judge that the suggested composite blade structure has enough stiffness and strength for the expected loading condition through the finite element analysis.