三维积叠线风力机叶片气弹自适应卸载机理与减载降噪一体化设计

The mass of wind turbine blades increases cubically or sub-cubically with the blade length, which brings severe challenges to the design of large-scale wind turbine system in the future. Novel wind turbine blade adaptive design concepts, with three dimensional stacking line, show great potential in limiting the blade loads and mass. The computational efficiency of the aero-elastic model based on blade element momentum theory (BEMT) has determined its indispensable role, but the inherent shortcomings of the classic BEMT will prohibit its applications on the blade with three dimensional stacking line. Therefore, improved bladed element momentum theory (IBEMT) will be developed on the basis of considering the influence of wake rotation and radial flow before-and-after the actuator disc. Coupling IBEMT model and the Geometrically Exact Beam model, a aero-elastic model of high efficiency and accuracy will be established. The new aero-elastic model is suitable for the geometrical non-linear and large-deformation blades with three dimensional stacking line, because its aerodynamics and structural dynamics formulations have intrinsic high abilities on these tasks. Coupled load alleviation mechanism will be collaborative studied between the aero-elastic tailoring of composite-materials blades and the adaptive characteristics of three-dimensional stacking line. Considering the connections between stacking line shape and aerodynamic noise propagation, integrated adaptive design considering the shape of three-dimensional stacking line and the tailoring of composite materials will be conducted. What is more, the new models and designs will be extensively validated and analyzed utilizing numerical methods and wind tunnel experiments data. This research plan is expected to provide effective COE-reduction methods for large-scale wind turbine rotors, and provide theoretical and technological basis for the wind energy trends towards large-scale and distributed-generation.

风力机叶片质量随叶片长度以三次方或亚三次方增加，给未来大型风力机的设计带来严峻挑战，采用三维积叠线自适应叶片的新型设计能够实现减载降重的效果。基于叶素动量理论的气弹模型计算效率优势决定了其不可或缺的地位，经典叶素动量理论存在的固有理论缺陷限制了其在三维积叠线叶片上的应用。本项目拟考虑尾流旋转和风轮前、后径向流动的影响，建立新型叶素动量理论模型，并耦合几何精确梁模型建立高效精准的气弹模型，该模型能从空气动力学、结构动力学的根源上适用于有三维积叠线和几何非线性大变形的叶片。协同研究复合材料叶片的气弹剪裁与三维积叠线的自适应之耦合卸载机制，并考虑积叠线形态与气动噪声传播的关联，对叶片的三维积叠线形态和复合材料剪裁进行一体化自适应设计。并采用数值仿真和实验结果对新模型、新设计进行广泛的验证和评价，以期为大型风力机降低COE提供有效方案，为风电大型化、分散式化提供理论和技术铺垫。

风力机风轮尺寸不断增大，直径已经达到200m量级，叶片的设计与应用在气动、气弹、噪声方面面临技术挑战与失效风险。风力机叶片质量随叶片长度以三次方或亚三次方增加，给未来大型风力机的设计带来严峻挑战，采用三维积叠线自适应叶片的新型设计能够实现减载降重的效果。本项目对三维积叠线叶片的空气动力学特性进行充分研究，探究了不同积叠线设计对气动特性的影响规律，发现了传统叶素动量理论在大变形迎风式和背风式叶片上的理论不兼容性，开发了适用于三维积叠线叶片的新型叶素动量理论模型。联合几何精确梁模型和多体动力学模型建立了气弹模型，新模型能适用于三维积叠线、大变形叶片，并对新模型进行了验证。基于气弹模型，研究了三维积叠线形态的自适应卸载机制，探寻了影响背风自适应性能的关键因素及其影响规律。对三维积叠线背风自适应风轮进行了减载降噪设计，进行了背风式风力机的创新设计，在国内外首次提出迎风——背风切换式风力机概念设计，申请并授权发明专利。本项目部分技术与成果已经在几家风电公司进行转化与应用，相关创新设计有望为未来大型风力机降低度电成本提供有效方案，为下一代超大型风力机设计提供理论和技术铺垫。