风力机翼型边界层分离流动三维特性的数值模拟

Numerical Simulation of 3D Characteristics of Boundary layer Separated Flow around Wind Turbine Airfoil

针对NRELS809翼型绕流流动分别建立了二维和三维可压缩湍流模型,并进行了相应的数值模拟计算。湍流黏度分别采用基于RANS的Spalart-Allmaras和k-ωSST两种湍流模型来处理。研究结果表明:基于RANS的三维Spalart-Allmaras湍流模型在大攻角下得到了更加细致的涡结构,且更能显示出边界层分离流动的三维特性,计算出的翼型气动性能与实验测试值更接近,因此,Spalart-Allmaras湍流模型比k-ωSST湍流模型在预测翼型失速后气动性能方面更加有效。数值计算结果同时揭示了分离流动的三维特性是影响翼型气动性能的重要因素,而二维模型并不适用于翼型气动性能的计算。

Both 2D and 3D compressible turbulence flow model were built to simulate the flow around NREL S809 airfoil in this paper.Then the steady compressible Reynolds-Averaged Navier-Stokes equations were solved numerically with one equation Spalart-Allmaras and two equations k-ω SST turbulence model respectively.The comparison with computed results and experimental data showed that more detailed vortex structure at high attack angles was obtained by using 3D Spalart-Allmaras model based on RANS,which was more capable of demonstrating 3D characteristics of boundary layer separated flow.Besides,the computed aerodynamic performance acquired by solving Spalart-Allmaras model approximately agreed with the experimental data.Therefore,Spalart-Allmaras model was more effective than k-ω SST model to predict the post-stall aerodynamic performance of the airfoil.Meanwhile,the numerical results revealed that 3D characteristics of separated flow had a strong impact on the aerodynamic performance after stall,and it was not suitable for 2D model to compute the boundary layer separated flow.