Design of high-efficient and universally applicable blades of tidal stream turbine

• A new method of tidal stream blade design based in Schmitz theory and optimization procedure was developed.
• This method solved the starting problem of low speed.
• Cavitations, stall, and separation were taken into full consideration.

The tidal stream turbine is the major device we use to obtain the kinetic energy of tides. The blades of the rotor are one of the essential parts which can convert tidal current energy into mechanical energy. Now most horizontal-axis turbine blade design theories are mostly based on the BEM (blade element momentum) theory and Glauert theory (e.g., WTperf, GHbladed). This paper comes up with a new method – Schmitz design. This method is easier, but they have the same physical philosophy. Also we change the chord length distribution to adapt the low stream velocity. This new hydrofoil increases the startup torque, improves the total performance of the turbine and decreases the thrust coefficient. At the same time we consider the incipient cavitations, tip loss and airfoil loss. We compare the design results with the experimental data in the literature. This method can satisfy the requirement of the design.