Coupled Blade-Hub Dynamics in Large Horizontal-Axis Wind Turbines

该项目的目标是加深我们对水平轴风力涡轮机叶片动力学的理解，以及它们对齿轮箱和轴承施加的载荷，最终为风力涡轮机设计师开发具有更高可靠性的涡轮机提供指导。风叶片动力学模型包括旋转、由重力和稳定风切变引起的循环激励（产生参数激励和直接激励）、气动弹性和任意阵风激励的影响。这项工作的重点是共振和不稳定性与几乎相同的风叶片耦合通过轮毂。这种对称布置容易产生振动局部化，增加了单个叶片的振动。该项目通过叶片和轮毂的基本建模、降阶建模和扰动分析来解决这些动力学问题，这些分析产生了关键行为的参数和机制的作用、高保真度模拟研究，包括齿轮和轴承上的传递载荷，以及模拟事件与国家可再生能源实验室和桑迪亚的现场观测结果的相关性。这项研究将为未知的动态载荷提供见解，这些载荷可能导致风力涡轮机过早失效。因此，这项工作使风能发电更加可靠和具有成本效益，从而促进可再生能源供应的多样化和减少温室气体。了解耦合叶片在直接和参数循环和气动弹性激励下的共振、局部化和不稳定性，以及对齿轮箱动载荷的影响，将为风力涡轮机工程师提供改进的设计指导，也将推动动力学领域的发展。研究结果将通过期刊出版物、会议报告、风能会议和讲习班传播。一名博士生和一名本科生将为风能工作做好准备。公团将通过现有的大学高中学生和超常中学生项目，开展外展活动。

The goal of this project is to deepen our understanding of the dynamics of horizontal-axis wind-turbine blades, and the loads that they impart to the gearbox and bearings, ultimately to provide guidelines for wind-turbine designers to develop turbines with significantly higher reliability. A wind-blade dynamic model involves effects of rotation, cyclic excitations due to gravity and steady wind shear (producing both parametric and direct excitation), aeroelasticity, and arbitrary wind-gust excitations. This work is focused on the resonances and instabilities associated with nearly identical wind blades coupled through the hub. Such symmetric arrangements are prone to vibration localization, which increases the vibration of a single blade. This project addresses these dynamics with fundamental modeling of the blades and hub, reduced-order modeling and perturbation analysis which yields the role of parameters and mechanisms underlying critical behaviors, high fidelity simulation studies that include the imparted loads on gears and bearings, and correlation of simulated events with field observations as available from the National Renewable Energy Laboratory and Sandia. This study will provide insight to the unknown dynamic loadings that can contribute to premature wind-turbine failures. The work thus enables a more reliable and cost-effective wind-energy fleet, which in turn promotes diversification of the renewable energy supply and the reduction of greenhouse gases. Understanding of resonances, localization, and instability of coupled blades with direct and parametric cyclic and aeroelastic excitation, and the effects on dynamic loading of the gearbox, will provide improved design guidelines for wind-turbine engineers, and will also advance the field of dynamics. Results will be disseminated through journal publications, conference presentations, and wind energy meetings and workshops. A doctoral student and an undergraduate will be prepared for the wind energy workforce. The PI will conduct outreach through existing university programs for high-school students and gifted middle school students.