基于外场实验的风力机叶片三维效应研究

Investigation of Three-Dimensional Effect on Blades of a Wind Turbine Based on Field Experiments

针对一台33 kW水平轴风电机组开展了外场实验,得到其叶片7个断面翼型的压力分布曲线;基于求解时均N-S方程对风轮进行三维数值模拟,以及将叶片各断面作为二维翼型进行数值计算,分别得到各断面翼型的压力分布曲线及升阻力系数.通过将外场实验、三维和二维数值计算所得压力分布曲线及升阻力系数进行对比分析,研究了三维效应对风力机气动性能的影响.研究表明,从叶尖到叶根各断面翼型的压差先增大后逐渐减小,叶片表面压力分布曲线比较明显地反映了从叶尖到叶根流动分离的变化;叶片表面压力分布的三维数值计算结果较二维计算结果更加接近于外场实验值;风力机叶片表面的三维流动对叶片的气动性能影响较大,在叶尖和叶根部分尤为突出.

Field experiments were performed on a 33 kW horizontal axis wind turbine. The curves of pressure distribution were gathered by 191 pressure sensors disposed span-ward on 7 particular sections of a blade. Then, the 3D numerical simulation of the wind turbine and 2D numerical simulation of the 7 airfoils were performed in comparison with the field experiment results, and the lift and drag coefficients of the 7 airfoils were also obtained for 3D and 2D. The investigation was performed for the turbine aerodynamic characteristics under the 3D effects. At last, conclusions were drawn. The pressure difference of the airfoils first increases and then de- creases from the blade tip to the blade root, and the curves of the pressure distribution show the characteristics of flow separation on the blade obviously. The 3D results of pressure on the 7 airfoils are more consistent with the experiments than 2D. There is a more violent 3D flow on the blade surface, especially at the blade tip and the blade root.