高湍流自由来流下风力机翼型性能预测方法研究

Free high stream turbulence resulting from the interaction of multi-scale atmosphere turbulence, wind shear and wind turbine wake, is one of the main sources leading to airfoil boundary instability, bypass transition and unsteady aerodynamic performance, especially for wind farms of low wind speed in China. These factors impose great challenge to the efficient, stable and safe operation of wind turbines. To design advanced airfoils with consideration of stability to varying free stream turbulence levels, the project of proposal will perform the following investigations: 1)Studying the transition mechanism of wind turbine airfoils subjected to high free stream turbulence with LES method. 2) Employing transition prediction methods based on transient growth theory, build the semi-experimental model of bypass transition by theoretical analysis, comparison and correlation with test data and numerical data by LES method. 3) Based on researches above, combining the new transition model with in-viscid and viscid interaction method to establish an improved panel method with fast and robust prediction, which could be an efficient and reliable prediction method to design wind turbine airfoils with stable performance under varying turbulence levels. The completion of proposal project will benefit revealing the effect of free stream turbulence on airfoil boundary layer transition, and provide a powerful support to specific-site design of wind turbine blades/airfoils for the regional development of wind power in China.

以低风速区为典型代表的实际风场中，多尺度大气湍流与风剪切、风力机尾流等耦合形成的高湍流自由来流是产生翼型流动失稳、复杂转捩模式和非定常气动特性的重要因素，形成了风力机叶片高效、稳定、安全运行的重要挑战。为实现风力机专用翼型在不同湍流工况下性能稳定的设计理念，申请课题拟开展：1）基于大涡模拟方法，获得风力机翼型高湍流自由来流湍流下的转捩特性；2）根据瞬态增长理论，通过理论推导、高精度数值模拟结果和翼型实验数据的对比研究，获得高湍流自由来流下翼型的转捩预测半经验模型；3）基于以上研究，改进无粘-粘性边界层迭代中基于线性稳定性理论的转捩预测方法，形成快速、高效的风力机专用翼型湍流效应预测手段，为实现复杂多变的来流条件下气动性能稳定的翼型设计提供可靠的预测工具。课题的完成将有助于揭示高湍流自由来流对翼型的转捩影响机制，为我国风能利用区域化发展中风力机叶片与翼型的精细化、定制化设计提供有力的支撑。

以低风速区为代表的实际风场中，多尺度大气湍流与风剪切、风力机尾流等耦合形成的高湍流自由来流是产生翼型流动失稳、复杂转捩模式和非定常气动特性的重要因素，形成了风电叶片高效、稳定、安全运行的重要挑战。项目研究通过数值模拟、风洞试验测试分析了实际风场中运行叶片的入流湍流特性，研究了自由来流湍流强度的变化对风力机翼型流动特性和气动力特征的影响，系统评估了低成本的RANS模型，无粘-粘性耦合迭代方法等对翼型高湍流效应的预测能力，并提出了高湍流条件下的翼型转捩与气动性能预测的修正方案；最后结合低风速、高湍流地区的风电开发技术要求，开展了考虑高湍流效应的翼型设计方法研究，引入湍流效应预测模块，建立了低风速风电叶片翼型设计方法；通过翼型案例设计与叶片应用研究验证了方案的有效性，为后续低风速区风电叶片翼型的定制化设计提供了技术基础。