Research On Stochastic Aerodynamic Performance Of Wind Turbine Based On BEM

There are many uncertain factors in the manufacturing,installation and operation of wind turbines,such as,the random fluctuation of natural inflow wind caused by surface topography and climate,the geometrical error and installation error of the blade caused by the complicated process of blade manufacture and installation,blade pitch angle uncertainty caused by variable propeller system,and so on.The coupling effect of these uncertain factors makes the aerodynamic performance of wind turbine fluctuate violently,which brings great challenges to the stability and reliability of wind turbine system.The purpose of this paper is to study the aerodynamic performance fluctuations of wind turbines caused by uncertain factors such as the input wind speed parameters,geometric errors and pitch angle errors.The uncertain aerodynamic characteristics of wind turbines in the direction of the blades were obtained through quantitative analysis of aerodynamic performance under uncertain conditions.The sensitivity of wind turbine to uncertain factors was reduced by the research of wind turbine blade uncertainty optimization.The aerodynamic stability of wind turbine was improved by the research of wind turbine blade uncertainty optimization.The influence law of random wind speed on the power output characteristics of the wind turbine was obtained by building a horizontal axis wind turbine aerodynamic performance test platform.This paper provides reference for aerodynamic design,geometric tolerance and precision control of wind turbine.The main research contents of this paper are as follows:1.The effect of random wind speed on the aerodynamic performance of wind turbine was studied.Based on the blade element momentum and the non-intrusive probabilistic collocation,an uncertain aerodynamic analysis model of wind turbine under random wind speed was established.The fluctuation range of aerodynamic performance of wind turbine under different wind speeds and the standard deviation of 5% to 15% of the mean wind speed was quantified.The distribution law of aerodynamic load and aerodynamic inductive factor uncertainty on the blade length under different wind speed standard deviation was obtained.2.The influence of blade geometry uncertainty on the aerodynamic performance of wind turbine was studied.Based on the blade element momentum and the interval analysis method,the geometric uncertain aerodynamic analysis model of wind turbine blades was established.The influences of geometric errors of chord length,twist angle and pitch angle on aerodynamic performance of wind turbine under different wind speeds were quantified.The distribution laws of aerodynamic performance uncertainty of wind turbine on blade spread length under different geometric errors and pitch angle errors were obtained.The sensitivity law of geometric error of wind turbine blade was analyzed through orthogonal test,and the sensitive position of wind turbine aerodynamic performance fluctuation affected by geometric error was obtained.3.Aerodynamic analysis and optimization of wind turbine under mixed uncertain conditions.Based on the blade element momentum,the non-intrusive probabilistic collocation and interval analysis method,the mixed uncertain aerodynamic analysis model of wind turbine was established.The influence degree of coupling effect of random factors on aerodynamic performance of wind turbine at different wind speeds was quantified.The distribution law of aerodynamic performance uncertainty on the blade length of wind turbine was obtained under different coupling conditions of random factors.Based on the established mixed uncertain aerodynamic analysis model and genetic algorithm,the uncertainty optimization research of wind turbine blade under different coupling conditions of random factors was carried out to reduce the sensitivity of wind turbine aerodynamic performance to uncertain factors,and to improve the aerodynamic stability of wind turbine.4.Experiment on the influence of random wind speed on power output characteristics of wind turbine.By building a test platform for the aerodynamic performance of a small horizontal axis wind turbine and making a scale model of the wind turbine,a test scheme for the uncertainty of wind turbine power and wind energy utilization coefficient under the condition of random wind speed was proposed.Based on this scheme,the uncertainty distribution rules of power and wind energy utilization coefficients under different wind speeds and standard deviations of wind speed were obtained.