Study Of Blade Design Method For Floating Wind Turbine Basin Model Test

With the rapid development of the world wind power market,as well as high quality wind farms being developed over,floating wind turbine is becoming the focus of wind power research in countries.Floating wind turbines are more complicated than onshore or offshore fixed foundation wind turbines and have higher technical requirements.Floating wind turbine's model tests must not be omitted when a conception from being introduced to the practical application.This paper discusses one of floating wind turbine model test key problems: the thrust of a geometrically similar model wind turbine is much smaller than the thrust required by theory,resulting in an inability to simulate the thrust and response of the wind turbine.The solution of this paper is to redesign a model blade which has thrust similarity with prototype blade.This paper analyzes the scale effects between prototype and model rotor,and discusses the reason why geometric model blade gives so small thrust.The model blade designing process starts with selecting an appropriate airfoil,and then basing on scale ratio evaluates model blade's Reynolds number environment.The 2D RANS method in FLUENT is used to calculate the lift and drag coefficients of the airfoil,besides that,these coefficients are validated by comparing with airfoil tunnel test data.In this paper,BEM theory and GDW theory which are coded in FAST,are used to calculate the working load of model blade.Furthermore,the geometric parameters of model blade are taken as independent variables.Next,the pattern search method toolkit in MATLAB is taken to search proper variables until design goal is reached.In the last,two different model blades are designed by these two theories.The CFD calculation results show that this two sets blade perform very well.According to the thrust coefficient map of model blade at different angles,the blade pitch angle in each test condition is determined to ensure the same thrust coefficient between prototype and model rotor.In this paper,a practical wind turbine model test bade design method is introduced,which greatly improves the model blade performance and meets the test requirements.This method has great reference and guiding significance to the related turbine model test researchers.