A new direct design method of wind turbine airfoils and wind tunnel experiment

Abstract

A general parametric representation function (Shape Function) for wind turbine – dedicated airfoils based on Taylor high-order polynomial series is presented for the first time. The design space and shape control function of the airfoil have been studied. The objective of the high-performance WT (Wind Turbine) airfoils was to maximise the lift/drag ratio at the design angle of attack both in free and fixed transitions. The optimised mathematical model of the airfoils is built combing genetic algorithm and the flow solver RFOIL. The new airfoil family (ranging in thickness from 15 to 20%) with target characteristics were designed for variable-speed operation with pitch control of large megawatt-sized rotors. Wind tunnel experiments for the WT180 airfoil were carried out for both clean and rough conditions. The experimental results for the lift and drag coefficients agree well with the RFOIL predictions. The testing verified the high lift/drag ratio and the high maximum lift coefficient for the WT180 airfoil. The results indicate that this novel design method is feasible to optimise wind turbine airfoils.