湍流强度对风机叶片风效应影响的试验研究

Experimental study on effect of turbulence intensity on wind effect with fan blade

湍流强度是影响风电机组疲劳载荷和极限载荷的重要因素之一,湍流本身是一个复杂的过程,难以用简单明确的方程表示或者预测,研究湍流显得更为重要。以某2MW大型风力机叶片为研究对象,首先基于风洞试验进行了在特定桨距角条件下考虑不同湍流强度对风机叶片表面气动分布的影响。在此基础上,结合有限元方法分析了在逆桨条件下叶片的动力特性与风振响应。研究表明:在0°桨距角时,下翼面平均风压系数基本不受湍流的影响,上翼面随着湍流的增大整体平均风压系数绝对值减小;脉动风压系数整体随湍流强度的增大呈现增大趋势。在90°桨距角时前缘部分为正压,随着湍流强度的增大平均风压系数逐渐减小;上、下翼面基本保持负压,随着湍流强度的增大平均风压系数绝对值逐渐减小。在0~90°桨距角中,随着桨距角的增大叶片的整体荷载显著降低。随着湍流强度的增大,顺风向位移均方差和位移极值均呈现逐渐增大的趋势。

Turbulence intensity is one of the important factors that affect the fatigue load and ultimate load of wind turbines.Turbulence is a complex process and it is difficult to express or predict with simple and clear equations.It is more important to study the statistical characteristics of turbulence.A 2MW large-scale wind turbine blade was taken as the research object.Firstly,based on the wind tunnel test,the influence of different turbulence intensity on the aerodynamic distribution of the fan blade surface was considered under the specific pitch angle condition.On this basis,combined with the finite element method,the dynamic characteristics and wind-induced response of the blade under the condition of propeller were analyzed.The research shows that at 0°pitch angle,the average wind pressure coefficient of the lower airfoil is basically not affected by turbulence,and the absolute value of the overall mean wind pressure coefficient decreases with the increase of turbulent flow on the upper airfoil;The overall pulsating wind pressure coefficient increases with the increase of turbulence intensity.At 90°pitch angle,the leading edge part is positive pressure,and the average wind pressure coefficient decreases with the increase of turbulence intensity;the upper and lower airfoil surfaces basically maintain negative pressure,and the average wind increases with the increase of turbulence intensity.The absolute value of the pressure coefficient is gradually reduced.At the 0°~90°pitch angle,the overall load of the blade decreases significantly increases as the pitch angle.With the increase of turbulence intensity,the mean square deviation and displacement extreme value of the downwind direction tend to increase gradually.