Aerodynamic Characteristics Of Low Reynolds Number Wind Turbine Airfoil Under High Turbulence

Wind turbine power generation technology is the main way of wind energy utilization.As an important supplementary form of distributed power energy,small wind turbines have attracted wide attention.Due to its low installation position,small wind turbines often operate under low Reynolds number and uncertain high turbulent flow conditions.Laminar flow separation occurs in the wind turbine airfoil boundary layer,and turbulence increases the instability of the blade surface flow.At the same time,there are many uncertain factors in the blade manufacturing process,such as manufacturing errors.These uncertainties have a serious impact on the aerodynamic performance and output power characteristics of the wind turbine,which in turn affects the stability and reliability of the wind power system.In this dissertation,aiming at the problem of wind turbine performance fluctuation caused by uncertain turbulence and manufacturing error,the aerodynamic performance analysis and optimization of small wind turbine airfoil under uncertain conditions were carried out to reduce the sensitivity of airfoil to uncertain factors and improve the aerodynamic stability and environmental adaptability of wind turbine.The main research contents of this dissertation are as follows:1.The effect of turbulence intensity on aerodynamic characteristics of low Reynolds number wind turbines was studied.Based on the modified transition SST model,the effects of different turbulence intensities(0.2%,5%,15%,25%)on lift drag characteristics and flow field structure characteristics of the airfoil S809 under low Reynolds number were studied.The effects of turbulence uncertainty on lift drag characteristics of the airfoil were quantified.The turbulence power calculation method was used to obtain the effects of turbulence intensities on the aerodynamic performance of small wind turbines.The effect of turbulence intensity on the power output and wind energy utilization coefficient of small wind turbines was quantitated.2.Aerodynamic optimization of wind turbine airfoils with high turbulence and low Reynolds number was carried out.Based on the improved Hick-henne parameterization method,the Transition SST model,the Latin hypercube sampling,the Kriging model and the genetic algorithm,the airfoil optimization design of airfoil S809 was carried out,and an airfoil design matching the actual turbulent wind conditions was obtained.3.Uncertainty analysis and optimization of aerodynamic performance of wind turbine airfoil under turbulent conditions were carried out.The effect of uncertainties of turbulence intensity,operational attack angle and manufacturing error on lift drag characteristics of S809 airfoil was analyzed by the Non-intrusive probability allocation method and Monte Carlo method.Based on Transition SST model,Non-intrusive Probabilistic Collocation Method,Monte Carlo method,Latin hypercube sampling,Kriging model and non-dominated sequencing genetic algorithm with elite strategy,the uncertain optimization of small wind turbine airfoil was studied to reduce the sensitivity of airfoil to turbulence intensity uncertainty,operational attack angle uncertainty and stochastic manufacturing error.