Optimized design of tidal current turbine blade at low current rate

Abstract

Blades have a significant influence on a tidal current turbine (TCT)’s energy transfer capacity. In order to ensure a blade working safely and efficiently in low flow rates, a special design is needed. Hydrofoil’s shape and blade’s quality are the key factors which affect blade’s dynamic and starting performance at low flow rate. In this research, basing on a 500 W_ORI blade (an initial design of 500 W tidal turbine’s blade), optimizations of hydrofoil and blade structure were done sequentially by genetic algorithm. After hydrofoil optimization we got optimized hydrofoil OPT_24 which has high dynamic performance, good startup performance and durable structure, then redesigned the shape of new 500 W_OPT blade (a 500 W tidal turbine’s blade using optimized hydrofoil). After that, the structure of 500 W_OPT blade was designed empirically and optimized to reduce its weight. Both 500 W_ORI and 500 W_OPT were fabricated, and their efficiency and the structure strength were tested. The experimental results show that the strain of the 500 W_OPT blade is smaller than that of the 500 W_ORI blade under the same load. The power efficiency of the 500 W_OPT at the optimal tip speed ratio is increased 500 W_ORI by 46.1%, and 500 W_OPT was able to start at the flow rate of 0.5–0.6 m/s.