大型风力机翼型静态气动性能的数值模拟

Numerical Simulation of Aerodynamic Performance for Large Wind Turbine

摘要: 本文对S809翼型的静态气动性能用CFD方法进行了数值模拟和分析，在计算过程中，使用了4种湍流模型对S809翼型进行了全湍流模拟，发现SST k-ω湍流模型的模拟效果与实验结果最为接近。但是大迎角状态下，S-A模型和k-ε模型预测的气流分离点较实验值靠后，导致升力显著高于实验值。另外，k-ε湍流模型算得的升力系数和k-ω湍流模型算得的阻力系数，与实验值的误差都比其他湍流模型大很多。之后又比较了SST k-ω湍流模型模拟的翼型几个状态下的表面压力分布和流场结构，研究了翼型静态失速下的气动性能。模拟结果显示，翼型边界层流动发生分离后，分离点在翼型吸力面上，且随着攻角的增大，分离点向前缘移动，直到整个翼型吸力面的边界层都发生了分离。当攻角足够大时，分离尾迹涡又重新附着在翼型壁面上，形成二次涡。

Abstract: In this paper, the writer uses the CFD method to numerically simulate the S809 airfoil which is specially used for large wind turbine and analyzes its static aerodynamic performance. In the calculation process, the writer uses Spalart-Allmaras turbulence model, k-ω turbulence model, k-ω turbulence model and SST k-ω turbulence model to make the fully turbulent simulation for S809 airfoil. It is found that the simulation result of the SST k-ω turbulence model is closest to the result of the experiment. Because the flow separation points predicted by the S-A and k-ω models are below the experiment result when the airfoil is at a high angle of attack, it will lead to the result that the lift force is significantly higher than the experimental values. In addition, the lift coefficient which is calculated by the k-ω turbulence model has larger error than other turbulence models, and the drag coefficient which is calculated by the k-ω turbulence model is also different with the experiment result. Then the writer compares the press distribution on airfoil surface and the flow field structure in some typical conditions which are simulated by the SST k-ω turbulence model, and researches the S809 airfoil’s aerodynamic performance under the static stall. The simulation result shows that the separation point is on the suction surface of the airfoil when the separation of airfoil’s boundary layer flow occurs. It is moving to the airfoil leading edge with the increasing angle of attack until the separation of all the boundary layer in airfoil suction surface occurs. When the angle of attack is large enough, the separation vortex of wake is reattached to the airfoil surface, forming the two-time vortices.