A novel methodology for the design of wind turbine dedicated airfoils and blade

Abstract

The present work proposed a novel methodology for the design of wind tur-bine dedicated airfoils and blade. The methodology addressed includes the application of a design strategy for the preliminary design stage of a horizontal axis wind turbine and usage of a systematic method to design the wind turbine dedicated airfoils. The blade design employs the blade element momentum theory to estimate the overall steady loads and performance. The efficiency and robustness of the traditional fixed point algorithm used to solve the blade element momentum equations is greatly improved. A new design strategy is applied to the redesign of a 10MW reference wind turbine blade. The results show that an increase in the energy output and a decrease in the levelised cost of the blade component are achieved. The existing airfoils series are generally designed at Reynolds number of the order of 3 million. Considering much larger Reynolds numbers are encountered for the large offshore reference wind turbine, a new airfoil series should be tailored to meet the demand. In this study, a systematic method will be developed to aid the dedicated airfoil design. A novel parametric method of intuitiveness, which called intuitive conformal transformation, is proposed. It can be found that the number of variables required to fulfill the geometric error tolerance has been reduced significantly for multiple airfoils compared with the advanced class shape transformation method. Meanwhile, an improved derivative of XFOIL, named MFOIL, is developed. Great improvement in the prediction accuracy of the 2D performance is achieved. In total, 16 variables are used to design a 35% thick flatback airfoil. A combination of airfoil performance at the clean condition and rough condition is selected as the design target. The genetic algorithm is used to find the optimal solution under the given constraints. The new 35% thick airfoil exhibits a much thicker trailing edge thickness than the traditional design and less sensitivity to the leading edge roughness. The overall performance of the new 35% thick airfoil outperforms the advanced Delft airfoil, DU00-W2-350. It can also be concluded that the systematic method can act as a reliable tool to aid the design of wind turbine dedicated airfoils.

Date of Award	1 Oct 2020
Original language	English
Awarding Institution	University of Nottingham
Supervisor	Xiaogang Yang (Supervisor) & Schubel Peter (Supervisor)