Design And Investigation Of Aerodynamic Performance Of Dedicated Airfoil Families For Horizontal-Axis Wind Turbines

As we know,wind energy,as one of important renewable energy resources,is getting more and more focus in recent years.Presently,the horizontal-axis wind turbine(HAWT) is the most popular style of wind turbines,where traditional airfoils for aircraft have been widely used in HAWTs.However,these kinds of airfoils often suffer noticeable performance degradation from roughness effect induced by leading-edge contamination.As a result,the ability of wind capture of wind turbines is weakened seriously.Therefore,new advanced dedicated airfoils are necessarily used to replace the old aircraft airfoils for modern large scale HAWTs.Nowadays, this has become the most essential problem in the field of wind turbine research.Investigation of advanced dedicated airfoils for HAWTs and their performance characteristics are presented in this dissertation.The research is a part of the National 863 project entitled "Design and Experimental Research on Advanced Wind Turbine Dedicated Airfoil Families". Specifically,a large amount of airfoils are collected to establish an airfoil database for wind turbines.The aerodynamics concerned with HAWT airfoils are then investigated to find the design goals of airfoil characteristics.The effect of some parameters on airfoil performances e.g. the maximum thickness and its location,leading edge roughness,Reynolds number,are studied. Two numerical simulation methods,based on linear-vorticity pane method and Navier-Stokes equations,respectively,are compared in terms of airfoil aerodynamics prediction.Furthermore,a direct airfoil design method is used to develop the CAS-W1 wind turbine dedicated airfoil family, including four airfoils thickness range from 15%to 25%.The Reynolds number is set at 3,000,000.The airfoils are designed to have both maximum lift coefficient and maximum lift/drag ratio.In addition,they are made insensitive to leading edge roughness by securing that transition from laminar to turbulent flow on the suction side occurs very near the leading edge for post stall angles of attacks.Meanwhile,wind tunnel testing is planned to validate the performances of the CAS-W1 airfoil family.Besides this,a numerical simulation method based on three-dimensional Navier-Stokes equations is also used to study the aerodynamic characteristics when three-dimensional flow separation occurs on the suction surface of an airfoil model in a wind tunnel.