Effects of Leading Edge Defect on the Aerodynamic and Flow Characteristics of an S809 Airfoil.
Effects of Leading Edge Defect on the Aerodynamic and Flow Characteristics of an S809 Airfoil.
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前缘缺陷对S809翼型气动和流动特性的影响
DOI：
10.1371/journal.pone.0163443
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Wang P
中科院分区：
文献类型：
--
作者：
Wang Y;Zheng X;Hu R;Wang P
风力涡轮机叶片在其运行寿命期间遭受雨滴、冰雹、昆虫或固体颗粒的连续冲击时，由于前缘缺陷而发生意外的性能下降。为了评估这个问题，本文数值研究了S809翼型的稳态和动态失速特性的各种前缘缺陷。本文研究了更多的前缘缺陷尺寸和更接近实际的参数。方法采用SST k-ω湍流模型进行了数值计算，并与已有文献资料进行了比较，验证了方法的有效性。为了确保计算收敛，连续性方程的残差在稳态和动态失速情况下被设置为小于10−7和10−6。模拟是用ANSYS Fluent 13.0软件进行的。结果在定常和动态条件下，气动系数和流场特性对前缘缺陷都很敏感。对于厚度为6%tc的翼型，前缘缺陷对S809翼型气动性能的影响相对较小。对于其他研究的缺陷厚度，在相对较小的缺陷长度下，前缘缺陷对翼型的流场结构、压力系数和气动特性的影响要大得多。例如，前缘缺陷出现后，升力系数急剧下降，阻力系数急剧增加。当缺陷长度足够大时，气动特性可以达到一个恒定值。当缺陷长度分别为0.5%c、1%c、2%c和3%c，缺陷厚度分别为6%tc、12%tc、18%tc和25%tc时，流场、压力系数分布和气动力系数变化不大。此外，研究还表明，临界缺陷长厚比为0.5，超过此值后，气动特性几乎保持不变。在动态失速状态下，前缘缺陷对翼型气动特性的影响比定常状态下更大。随着缺陷长度的增加，分离区强度增大，并沿吸力面沿着向前移动。结论前缘缺陷对翼型的气动特性和流动特性有显著影响，当缺陷尺寸足够大时，翼型的气动特性和流动特性将趋于稳定。前缘分离泡、缺陷空腔环流和强烈的后缘涡是缺陷翼型绕流的主要特征。
Background Unexpected performance degradation occurs in wind turbine blades due to leading edge defect when suffering from continuous impacts with rain drops, hails, insects, or solid particles during its operation life. To assess this issue, this paper numerically investigates the steady and dynamic stall characteristics of an S809 airfoil with various leading edge defects. More leading edge defect sizes and much closer to practical parameters are investigated in the paper. Methodology Numerical computation is conducted using the SST k-ω turbulence model, and the method has been validated by comparison with existed published data. In order to ensure the calculation convergence, the residuals for the continuity equation are set to be less than 10−7 and 10−6 in steady state and dynamic stall cases. The simulations are conducted with the software ANSYS Fluent 13.0. Results It is found that the characteristics of aerodynamic coefficients and flow fields are sensitive to leading edge defect both in steady and dynamic conditions. For airfoils with the defect thickness of 6%tc, leading edge defect has a relative small influence on the aerodynamics of S809 airfoil. For other investigated defect thicknesses, leading edge defect has much greater influence on the flow field structures, pressure coefficients and aerodynamic characteristics of airfoil at relative small defect lengths. For example, the lift coefficients decrease and drag coefficients increase sharply after the appearance of leading edge defect. However, the aerodynamic characteristics could reach a constant value when the defect length is large enough. The flow field, pressure coefficient distribution and aerodynamic coefficients do not change a lot when the defect lengths reach to 0.5%c,1%c, 2%c and 3%c with defect thicknesses of 6%tc, 12%tc,18%tc and 25%tc, respectively. In addition, the results also show that the critical defect length/thickness ratio is 0.5, beyond which the aerodynamic characteristics nearly remain unchanged. In dynamic stall, leading edge defect imposes a greater influence on the aerodynamic characteristics of airfoil than steady conditions. By increasing in defect length, it is found that the separated area becomes more intense and moves forward along the suction surface. Conclusions Leading edge defect has significant influence on the aerodynamic and flow characteristics of the airfoil, which will reach a stable status with enough large defect size. The leading edge separation bubble, circulation in the defect cavity and intense tailing edge vortex are the main features of flow around defective airfoils.
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11.2
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DOI：
10.1016/j.jweia.2010.06.007
发表时间：
2010-12-01
影响因子：
4.8
作者：
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通讯作者：
Sundsbo, Per A.