Objectives A multi-objective optimization algorithm is proposed for the problem of complex operating conditions of large horizontal axis hydraulic turbine blades.
Methods An airfoil optimization model is established based on the multi-island genetic algorithm, and the airfoil is parametrically fitted using the CST function method, and the whole optizisation process is integrated in the Isight platform to achieve automatic optizisation.
Results Using the above method, NACA63816, NACA63815 and NACA63813 airfoils were selected as the initial airfoils for multi-objective optizisation, and the CFD numerical validation was carried out on the obtained airfoils using the Fluent turning model, and the lift-to-drag ratios and lifting forces at the airfoil angle of attack of 5° were selected as the optizisation objectives, which resulted in the optizised airfoils having a lift coefficient increased by 20%, 15%, 14%, and lift-to-drag ratios increased by 28%, 16%, 14%, respectively.
Conclusions Numerical validation shows that the lift-to-drag ratio of the optimised airfoil is higher than that of the original airfoil with the same thickness under several operating conditions, and the structural strength of the blade is improved while having good aerodynamic performance, which makes it more suitable for large-scale tidal current energy horizontal axis hydraulic turbines compared with conventional airfoils.
DownLoad: