Active Micro-Tabs for Load Control on Wind Turbine Blades

现代大型风力涡轮机叶片受到强烈的局部和非定常风条件的影响，例如风切变、阵风和叶片-塔架相互作用。这些效应导致动态失速，从而加速各种结构部件的疲劳。因此，风力涡轮机的寿命显著缩短，这增加了能量的总成本。控制动态负载变化的手段是通过具有主动元件的流量控制来提供的。然而，其应用的瞬态效应以及动态失速对控制元件的影响尚未得到适当的解决。因此，需要对这些主题进行额外的研究，以使有源负载控制方法在全尺寸风力涡轮机上的应用成为可能。通过所谓的微突片提供了一种有效载荷控制的有前途的工具，微突片可以展开和缩回以抵消突然的载荷变化。微突片系统是有利的，因为它的机械简单性、在叶片结构内的不复杂的实施方式以及实质性的控制权限。微型翼片应用于后缘区域，当在吸力侧展开时，微型翼片减小升力，当在压力侧展开时，微型翼片增强升力。然而，由于动态失速的发生，吸力面上的翼片嵌入分离流中，这使得翼片无效。因此，提出了一种研究微突片与失速延迟涡发生器组合的实验方法。该项目的主要重点是研究展开和收缩过程中的瞬态效应以及动态失速的影响。此外，在现实条件下的闭环配置的瞬时负载控制的可行性进行了研究。

Modern large wind turbine blades are affected by strong local and unsteady wind conditions such as wind shear, gusts, and blade-tower interaction. These effects lead to dynamic stall and thereby accelerate the fatigue of various structural components. Therefore, a wind turbine's life time is significantly reduced which increases the overall cost of energy. The means of controlling dynamic load changes is provided through flow control with active elements. However, transient effects of their application as well as the effects of dynamic stall on the control elements have not been properly addressed yet. Therefore, additional research is required on these subjects to enable the application of active load control methods on full-scale wind turbines. A promising tool for effective load control is offered through so-called micro-tabs which may be deployed and retracted to counteract sudden load changes. The micro-tab system is advantageous because of its mechanical simplicity, uncomplicated implementation within the blade structure, and substantial control authority. Micro-tabs are applied at the trailing edge region where they reduce lift when deployed on the suction side and enhance lift when deployed on the pressure side. However, due to the occurrence of dynamic stall, the tab on the suction is embedded in separated flow which renders the tab ineffective. Therefore, an experimental approach to study a combination of micro-tabs with stall delaying vortex generators is proposed. The main focus of this project is the investigation of transient effects during the deployment and retraction process as well as the effects of dynamic stall. Furthermore, the feasibility of instantaneous load control in a closed-loop configuration under realistic conditions is examined.