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，以及它们传递给齿轮箱和轴承的载荷，最终为风力涡轮机设计师提供指导，以开发具有更高可靠性的涡轮机。 风力叶片动态模型涉及旋转效应、重力和稳定风切变（产生参数和直接激励）引起的循环激励、气动弹性和任意阵风激励。 这项工作的重点是共振和不稳定性与几乎相同的风力叶片耦合通过轮毂。 这种对称布置易于振动局部化，这增加了单个叶片的振动。 该项目解决了这些动态与基本建模的叶片和轮毂，降阶建模和扰动分析，产生的关键行为，高保真度仿真研究，包括齿轮和轴承上的施加载荷的参数和机制的作用，以及相关的模拟事件与现场观察，可从国家可再生能源实验室和桑迪亚。 这项研究将提供洞察未知的动态负载，可能会导致过早的风力涡轮机故障。 因此，这项工作能够实现更可靠和更具成本效益的风能船队，这反过来又促进了可再生能源供应的多样化和温室气体的减少。 了解耦合叶片的共振、局部化和不稳定性，以及直接和参数循环和气动弹性激励，以及对齿轮箱动态载荷的影响，将为风力涡轮机工程师提供改进的设计指南，也将推动动力学领域的发展。 研究结果将通过期刊出版物、会议介绍以及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劳动力做好准备。 PI将通过现有的高中生和有天赋的中学生的大学课程进行外展。

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.