大型风力机叶片腹板偏置对弯扭耦合特性研究

STUDY ON BEND-TWIST COUPLING CHARACTERISTICS OF WEB OFFSET FOR LARGE WIND TURBINE BLADES

为研究大型风力机叶片内部腹板结构偏转对叶片弯扭耦合特性的影响,基于NX二次开发建立NREL 5 MW叶片CAD模型,通过计算流体力学(Computational Fluid Dynamics,CFD)方法求解叶片表面的分布载荷,采用节点位移法求解叶片弯曲角及扭转角,分析腹板偏置对叶片弯扭耦合效应的影响。结果表明,偏置腹板可使叶片产生自适应特性;在气动载荷作用下,弯曲角与扭转角均沿叶展逐渐增大,于叶尖达到幅值;正向偏置时,叶片扭转角与偏转幅度呈负相关,反向偏置与之相反;正偏置结构耦合叶片弯扭耦合系数随偏转角增大呈递减趋势,反偏置叶片均大于传统叶片。

In order to research the influence of the web deflection on the bend-twist coupling characteristics of large wind turbine blades,the CAD model of NREL 5 MW blade is established based on NX secondary development,the aerodynamic loads of the blade are obtained by CFD method,the blade bendind angle and twisting angle are solved by the node displacement method to analyze the influence of web deflection for bend-twist coupling blade.The results show that the offset web helps to achieve the bend-twist coupling of blades.Under the action of aerodynamic load,the bending and twisting angle both increase along spanwise direction of blade gradually,and reach the magnitude at the tip of the blade;in forward bias,negative correlation between twist angle and offset,reverse bias is the opposite;positive bias blades bend-twist coupling coefficient is decreasing trend with the increase of deflection angle,reverse bias blade are greater than the conventional blade.