旋转与涡流发生器耦合效应下风力机叶片流动控制机理研究

There exits the coupling effect between vortex generators(VGs) and rotation of blade which creates trailing vortex, shedding vortex, rotation effect and dynamic stall happening in the wind turbine. The coupling effect makes the angle of attack, separation vortex, stall type and inflow angle of VGs changed much compared with those of a single aerofoil. The mechanism of flow control under the coupling effect is a key problem to optimally apply VGs on wind turbine blade, and must been solved in the future. The present researches investigating flow control of VGs are mainly conducted on two kinds of objects: single aerofoil or blade. While, the former researches didn’t consider the effect of rotation, the latter mainly focused on the final effect of VGs on overall aerodynamic performance of blade; therefore, both of them still didn’t solve the problem efficiently. The project will propose an approach of parametric modeling for VGs arrays to efficiently and accurately simulate the structure of the detached eddy of VGs firstly, by considering the vortex induction between individual VG blades. Then, the parametric model combined with vortex method, CFD, fluorescence oil-film technique and other wind tunnel experiments will be used to carry out further researches under different coupling conditions, from one factor to several factors (trailing vortex, shedding vortex, rotation effect and dynamic stall), from root to tip of wind turbine blade. The detailed researches are including: ①The mechanism of VGs controlling flow on aerofoil will be re-researched based on a blade element instead of a single aerofoil which was employed in traditional research, to make clear the rules of inter-action between the rotation and VGs. ②The project will deeply research the flow details and their changes’ trends of flow on wind turbine blade under the control of VGs. The project will establish connection between the mechanism of flow control on single aerofoil and the final effect of VGs on rotating blade, and promote development of VGs from optimum application on single aerofoil to that on rotating wind turbine blade, and then provide theoretic indirections to enlarge the efficiency of all the large-size wind turbines.

涡流发生器（VGs）与旋转叶片尾随涡、脱体涡、旋转效应和动态失速等因素存在耦合效应，使叶片攻角、分离涡、失速类型和VGs入流角较孤立翼型的发生明显变化，该效应下流动控制机理是风力机优化应用VGs所面临的关键问题。目前研究基于孤立翼型和叶片展开，前者未考虑旋转影响，后者重在VGs效果验证，均未有效解决此问题。本项目首先考虑VGs叶片间涡系诱导对脱落涡影响，提出阵列式VGs参数化建模方法，实现旋转叶片表面VGs脱落涡结构的高效和精确模拟。然后结合涡方法、CFD模拟和荧光油膜全局摩擦力等风洞试验，从单因素到多因素、叶根到叶尖等多种耦合条件：①基于叶素重新审视VGs对翼型流动控制的机理，阐明旋转与VGs耦合作用机制；②揭示VGs对风力机旋转叶片流动的控制作用规律。研究为孤立翼型控制机理与旋转叶片控制效果之间建立有机联系，促进VGs优化应用从孤立翼型向旋转叶片发展，为大型风力机效率提升奠定理论基础。

涡流发生器（VGs）是一种被动流动控制技术，目前已经被广泛应用于风力机，然而这些应用设计主要基于二维翼型展开。风力机叶片表面的流动受到了叶片尾随涡、脱体涡、三位旋转效应以及动态失速等因素的影响，比二维翼型表面的流动更加复杂。所以，本项目考虑以上因素，深入分析三维流动作用下VGs的控制机理，对风力机叶片上VGs的优化应用具有重要的指导意义。.本项目按照项目初始设计思路，首先建立VGs阵列式参数化建模方法；然后基于Phase VI风力机，逐步分析单因素下叶素表面VGs控制机理、多因素下叶素表面流动控制机理和多因素下叶片表面流动控制机理来展开研究。得了下研究成果：.首先，建立了阵列式反向旋转VGs的参数化模型。研究发现VGs参数化建模方法除了要建立高精度的数学模型外，其模拟方法对模拟精度同样非常重要。为此，本项目通过平板和翼段来验证和分析VGs参数化的数学模型和模型的模拟方法，与试验和CFD仿真结果吻合良好。.其次，分析了脱体涡、尾随涡和两种涡系共存作用对VGs的流动控制机理研究。针对Phase Vi风力机建立等环量分布的几何模型，以实现不同涡对VGs控制的影响规律。.其次，分析了VGs对动态失速的抑制作用规律，研究针对DU91-W2-250翼型和S809两种翼型展开，分析了VGs形状、位置和间距等对抑制效果的作用规律，得到了矩形抑制效果好于梯形和三角形的结论，并从涡核轨迹、VGs脱落涡强衰减程度等角度解释了相关现象。.最后，基于Phase VI叶片分析了三维旋转效应对VGs的作用规律。研究发现三维旋转效应具有抑制分离的作用，三维旋转效应与VGs作用下抑制作用更加明显。同时，也发现三维旋转效应造成叶片表面比较显著的展向分速度，导致流动不再垂直于VGs阵列流入，在这种情况下同向VGs性能可能由于反向VGs。项目对三位旋转效应下同向VGs和反向VGs的效果进行对比分析，得到了同向VGs在一定间距下可以避免VG间的干扰，同时控制效果也由于反向的重要结论。.本项目按照计划完成了所有工作，并发表了50余篇高水平的学术论文，申请了10项发明专利。