Aerodynamic Performance Analysis And Optimization Design Of Wind Turbine With Iced Airfoil

In recent years, the horizontal axis wind turbine have received more and moreattention and developed rapidly, but when it is set in cold region, wind turbine bladesurface will produce icing in winter. Blades are the most important part of wind turbinegenerators, and its sectional profiles, namely airfoil, is the most fundamental geometricfact, which plays a key role in determining the wind turbine aerodynamic and loadperformance. After the airfoil ice up，its aerodynamic performance will be reducedgreatly, thereby the power generation efficiency of wind turbine will be affected. Thisshows that，iced profile prediction，the aerodynamic performance analysis of icedprofile and optimization design in icing conditions are very important.This work is supported by a grant from the National High Technology Researchand Development program of China (863Program, No.2012AA051301) and NationalNatural Science Foundation of China (No.51175526). Therefore, in this paper, theresearch topic is presented named aerodynamic performance analysis and optimizationdesign of profile for wind turbine under icing conditions. The method of RFOIL andcomputational fluid dynamics (CFD) are used to calculate the aerodynamic performanceof airfoil under icing conditions，a design method of wind turbine airfoil is presentedand a new airfoil with relative thickness of18%called ICE180is optimized undertypical rime icing conditions， the method called CFD is used to validate theaerodynamic performance of optimization result. In this dissertation, the main work andresults are summarized as follows:①The research process of airfoil icing problems and wind turbine airfoil issummarized up at home and abroad in detail.The geometric parameters of the airfoil，thedesign method of airfoil and the prediction method of airfoil aerodynamic performanceare described，which lays a good foundation for the subsequent study of airfoil icingproblems.②The mechanism of airfoil icing up，the affecting factors of airfoil icing up andthe freezing type are discussed. The software called LEWICE is used to calculate theshape of icing airfoil under rime and glaze icing conditions. Then the aerodynamicperformance of iced airfoil is calculated，the results show that，lift coefficient changeslittle，to some extent，lift-to-drag ratio decreases in the range of main attack anglesunder rime icing conditions；lift coefficient decreases，lift-to-drag ratio decreases greatly in the range of all attack angles under glaze icing conditions，which has a seriousinfluence on the aerodynamic performance of wind turbine.③Based on the expression method of airfoil shape, a design method of windturbine airfoil is presented and a new wind turbine airfoil with relative thickness of18%called ICE180is optimized under typical rime icing conditions. The method called CFDis used to validate the aerodynamic performance，the results show that, compared to theairfoil WT180, the new airfoil ICE180keeps good aerodynamic performance under noicing up conditions. Besides, its aerodynamic performance is greatly improved and thethickness of leading edge ice accretion is reduced when iced up in the range of mainattack angle.