基于最大风能利用系数的风力机翼型设计

Design of Wind Turbine Airfoils Based on Maximum Power Coefficient

以叶素动量理论为基础,对翼型风能利用系数进行循环迭代以求解其最大值,同时分析翼型在各段升阻比范围内升阻比增加对风能系数的影响。针对风力机展向各处对翼型设计的不同要求,基于翼型型线与噪声预测理论,综合考虑翼型的前缘粗糙度敏感性、非设计工况特性、失速特性、噪声特性以及风力机的使用寿命,提出以多攻角范围内翼型风能利用系数为设计目标来设计翼型的新方法。计算实例选取相对厚度为18%的翼型进行优化计算,得到一种性能优越的风力机专用翼型,通过和风力机常用翼型NACA 63418在雷诺数Re=2×106和Re=6×106下自由转捩和固定转捩两种工况时性能的综合比较,新翼型在5°～14°攻角范围内具有良好的粗糙度敏感性、非设计工况特性、失速特性以及低噪声,同时也具有更高的风能利用系数,很好地满足了风力机专用翼型的设计要求。

Based on the blade element momentum（BEM） theory,the power coefficient of a wind turbine can be expressed in function of local tip speed ratio and lift-drag ratio.By taking the power coefficient in a predefined range of angle of attack as the final design objective and combining with an airfoil noise prediction model,the previously developed integrated design technique is further developed.The new code takes into account different airfoil requirements according to their local positions on a blade,such as sensitivity to leading edge roughness,design lift at off-design condition,stall behaviors,noise emission as well as wind turbine service life.To show the performance of the new design technique,a new airfoil with relative thickness of 18% is designed.Comparisons with a wind turbine airfoil（NACA 63418） at Re=2×106 and Re=6×106 for free and fixed transitions show that the new airfoil has a higher power efficiency,better designed lift at off-design condition,better stall behavior,less sensitivity to leading edge roughness and lower noise emission.