大型风电叶片仿生流动控制机理与优化研究

The large-scale wind turbine blade has always faced with some unsolved problems, e.g. viscous drag loss, flow separation and noise, to affect the efficiency, reliability and security of the turbine system. To this end, different from traditional solutions, in this proposed project, three new types of bionic based effective flow control methods, i.e. drag reduction by mimicing shark-surface riblet, separation control by mimicking whale-leading edge tubercle and noise suppression by mimicing owl-trailing edge sawtooth, are introduced to conduct the corresponding researches: 1) to predict unsteady flow and acoustic fields, the advanced Large Eddy Simulation method will be developed, based on non smooth surface model, and high-stability, low-dissipation and -dispersion numerical scheme. 2) Utilizing 3D high-frequency PIV and unsteady CFD methods, the advanced high-efficient and high-precision experimental technique will be created, and the experimental analysis methods of flow and acoustic fields, characterized by high-efficiency and high-stability, will be developed and utilized to verify the developed numerical methods. 3) On account of local vortex dynamic theory, together with the developed advanced experimental and verified numerical methods, the mechanisms and corresponding physical models of the bionic based flow control approach will be uncovered and the optimum design method of the bionic structures (i.e. riblet, leading edge tubercle and trailing edge sawtooth) will be also proposed. 4) the large-scale blade utilized the bionic method will be further evaluated and validated through engineering application in terms of aerodynamic and aero-elasticity. The outcome of the proposed project will not only lay a solid foundation on the formation of “independent innovation blade design technology system” contained the connotation of bionics, but provide a reference for solving similar problems in the field of fluid machinery.

大型风电机组叶片运行过程中通常存在粘性摩阻、流动分离和噪声等气动问题，严重妨碍机组在效率、可靠性和安全性等方面性能改善。为此，申请项目拟采用仿鲨鱼皮肋条减阻、仿鲸鱼鳍流动分离控制和仿猫头鹰翅膀尾缘降噪等有别于传统的仿生流动控制方法，主要研究内容和技术路线包括：1）发展基于非光滑表面模式化模型和高稳定、低耗散、低色散计算格式的先进流场、声场LES模拟方法，预测和分析叶片非定常流场和声场；2）发展基于三维高频PIV和非定常CFD的仿生叶片高效、高精度速度场先进实验方法及高效、高可靠的流场、声场实验分析方法，并验证数值计算方法；3）结合先进实验和已验证计算方法，开展基于局部涡动力学理论的叶片仿生流动控制机理和物理模型研究，并提出仿生结构优化设计方法；4）开展大型仿生叶片气动和气弹应用验证研究，为形成具有仿生学内涵的“叶片自主创新设计技术体系”奠定基础，同时为解决流体机械领域类似问题提供参考借鉴。

大型风电叶片运行中通常存在摩阻损失、流动分离和旋转噪声等问题，严重妨碍机组在效率、可靠性和度电成本改善。为此，本项目采用仿鲨鱼皮肋条减阻、仿鲸鱼鳍凹凸前缘流动分离控制和仿猫头鹰翅膀锯齿尾缘降噪等有别于传统的仿生学方法，开展了叶片仿生流动控制机理与优化设计创新性研究。主要包括：1）为准确评估分析仿生叶片周围复杂三维湍流边界层特征及其对叶片流场、声场的影响规律，发展了高稳定、低耗散、低色散数值格式，涡动力学诊断与稳定性分析方法及基于可穿透边界FW-H方程的噪声预测算法；2）为获得仿生叶片近壁区更加精细化的流场、声场信息，开发了基于子波分析的猝发结构辨识、基于能量谱的尺度分解和涡识别诊断、基于PIV与URANS的非定常速度场测量以及反卷积声源定位等高效、高可靠风洞实验方法；3）揭示了控制机理在于仿生结构诱发的三维局部涡系运动对原有边界层中主导涡场的对流、扩散及耗散等涡动力学演化过程产生了不同程度的抑制作用，直接削弱了湍流边界层的能量输运和相应速度场、压力场脉动变化；4）构建了反映三种仿生结构流场特点的模化模型，开发了叶片仿生结构优化设计方法。项目的有效实施打破了过去国际同行的认识局限，促进了相关领域的学术发展；应用研发的仿生技术于大型兆瓦级商业风力机叶片，有效地提升了国内知名整机企业—国电联合动力兆瓦级叶片乃至机组在年发电量、疲劳载荷、噪声等性能，获得了中国能源创新奖一等奖和中国电力科学技术进步二等奖，为公司后续叶片开发提供了坚实的技术支持；作为前期重要技术基础之一，项目组与金风科技、浙江运达和国网电科院等国内知名风电企业合作，获批“十四五”科技部国重项目，在我国超大型海上固定和漂浮式风电机组叶片研发中将发挥积极作用；为形成具有仿生学内涵的“叶片自主创新设计技术体系”奠定基础，有利于大幅提升我国风电叶片设计能力，打破了国外垄断，同时也将为解决叶轮机械领域存在的类似问题提供必要的理论和技术储备。