Vertical-Axis Wind Turbine Blade Vibration Modeling for Improved Reliability

到2030年，实现美国20%的能源来自风能的目标将需要多样化的风能采集机。 各种类型和不断增大的尺寸的风力涡轮机将需要安装在包括离岸海岸的各种环境中。 维护和修理非常大的涡轮机可能是昂贵的，并涉及大量的停机时间，从而挑战负担得起的风能的发展。 目前，水平轴风力涡轮机（HAWT）是最流行的类型，垂直轴风力涡轮机（VAWT）是下一个最常见的。 阻碍VAWT发展的一件事是它们具有振动和疲劳问题的名声。 这一声誉早在现代刀片材料开发之前就已确立。 但是VAWTs有一些重要的优势。 这些包括独立的风向，减少塔的大小，降低质心，并降低发电机的位置。 此外，HAWT尺寸可能受到重力的限制。 此外，VAWT效率提高时，放置在风电场阵列。 因此，VAWT可能在某些应用中更好，包括大型离岸装置，因此重新受到关注。 迄今为止，VAWT的建模深度远低于HAWT。 这些情况都需要更好的模型，VAWT，包括VAWT叶片振动。 本文的目的是建立一个VAWT叶片振动模型，并利用该模型来了解VAWT叶片参数对振动的作用，以便将来设计可靠的VAWT。在这项工作中，H-转子VAWT叶片的振动模型将制定。 H型转子叶片的简单几何形状允许工作集中在VAWT功能的力学复杂性上。 该模型将包括非线性梁理论和非线性气动力的半经验模型。 对模型的初步了解表明存在参数和直接激励以及非线性，所有这些都可以相互作用，产生各种共振和不稳定性。 降阶建模和渐近分析将导致共振和不稳定性的识别。 将对临界情况进行更深入的数值模拟。 其结果将是共振和VAWT叶片的不稳定性的机制，以及参数的作用的理解，导致设计建议，以提高可靠性，降低维护成本，减少停机时间。

Meeting the goal of 20 percent US energy by wind by 2030 will require a diverse fleet of wind energy harvesters. Wind turbines of various styles and of increasing size will need to be installed in a variety of environments including off shore. Maintenance and repair of very large turbines can be costly and involve significant down time, thereby challenging the development of affordable wind energy. Currently, horizontal-axis wind turbines (HAWTs) are the most popular type, with vertical-axis wind turbines (VAWTs) being the next most common. One thing that has hindered the development of VAWTs is their reputation for having vibration and fatigue problems. This reputation was established well before the development of modern blade materials. But VAWTs have some important advantages. These include independence of wind direction, reduced tower size, lower center of mass, and lower generator placement. Furthermore, HAWT size may be limited by gravity. Also, VAWT efficiency improves when placed in wind-farm arrays. Thus, VAWTs may turn out to be better for some applications, including large off-shore installations, and are therefore getting renewed interest. To date, VAWTs have been modeled in much less depth than HAWTs. These circumstances all converge to the need for better models for VAWTs, including VAWT blade vibration. The purpose of this work is to develop a model for VAWT blade vibration, and to use the model to understand the role of VAWT blade parameters on vibration, to enable the design of reliable VAWTs in the future. In this work, vibration models of H-rotor VAWT blades will be formulated. The simple geometry of H-rotor blades allows the work to focus on the complexity of the mechanics of VAWT function. The model will include nonlinear beam theory and a semi-empirical model of the nonlinear aerodynamic forces. Preliminary insight into the model suggests the existence of parametric and direct excitation, and nonlinearity, all of which together can interact to produce a variety of resonances and instabilities. Reduced-order modeling and asymptotic analysis will lead to identification of resonances and instabilities. Critical cases will be simulated numerically in more depth. The result will be an understanding of the mechanisms of resonances and instabilities of VAWT blades, as well as the role of parameters, leading to design recommendations for increased reliability, reduced maintenance costs, and less down time.