Tidal turbine hydrofoil optimization design based on NURBS and genetic algorithm

Key words:  turbines  airfoil profile  lift-drag ratio  power coefficient  multi-objective genetic algorithm

Abstract:

The performance parameter of marine current blade is one of the important factors that determine the efficiency of turbine, so how to construct the blade profile is a key problem in the design process. In this study, the NURBS curve was used to parameterize the turbine blade profile, and the constructed blade profile agrees well with the original one, meanwhile the fitting accuracy is very high. The blade profile performance parameter samples are obtained by using the fluid calculation method and XFOIL software. Then multi-conditions optimal design was performed for the lift-drag ratio of the NACA4415 airfoil profile. Optimization results show that the performance of the lift-drag ratio is improved in the condition of attack angle design, and the increasing amplitude increases with the increase of the attack angle. The power coefficient based on the optimal airfoil profile also increases compared with the original one, and it is increased by 7％ around when the propeller pitch angle is 6°. The results validate the rationality and validity of the proposed optimal problem.