Studies on Vertical Axis Wind Turbines Technologies

垂直轴风力发电机技术研究

• 批准号: RGPIN-2015-05739
• 负责人: Nitzsche, Fred
• 金额: $ 1.6万
• 依托单位: Carleton University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=660992
• 关键词: Studies; Vertical; Axis; Wind; Turbines

The aeroelastic and aero-acoustic behaviour of Darrieus-type vertical axis wind turbines (VAWT) individually and in wind farm formations will be investigated. Darrieus wind turbines were common in the 1970's but they were phase out due to problems with excessive vibrations. Advances in "smart" control systems and blade pitch control to suppress vibrations and the advent of composite blade structures have revitalized this conceptual design nowadays. In addition, the necessity of building offshore wind farms in deeper water to minimize the unavoidable visual and noise pollution near populated areas have pushed the industry to consider floating wind turbines. Horizontal axis wind turbines are not appropriate to floating installations due to its inherent stability problems.******The "troposkien" (from the Greek "rotating rope") geometry minimizes the fatigue of the Darrieus blade. The structural dynamic behavior of the "troposkien" blade under the action of the unsteady aerodynamics will be investigated considering the non-linear effects due to both the structural curvature of the blade and the aerodynamic dynamic stall present in regions of the blade azimuth angle. The structural dynamics will be expressed in a state-vector mixed formulation form where both forces and displacements in the in- and out-plane directions will be considered as the dependent variables. The aerodynamic simulation of the VAWT will be developed incorporating a free-wake vortex model where each blade section will shed vortices due to the changes in the blade lift over time. The shed vortices (filaments or alternatively particles) will be let to evolve over space in a Lagrangian description of the flow by the velocity field induced by both the vorticity of the neighbouring vortices and the wind free speed. Tower (blunt-body) effects will be included for a better description of the flow. This numerical approach is computationally efficient to represent the free-wake in rotating wings as it is mash-less and so robust to unrealistic numerical dissipation of the vortex strength normally encountered in traditional (grid-based) computational fluid dynamics methods. Coupling the aforementioned models for the structure and the aerodynamics both the self-excited (flutter and limit cycle oscillations) and the aeroelastic forced response of the structure due to the unsteady dynamic and aerodynamic loading will be investigated numerically. Aero-acoustic emissions generated by the unsteady acoustic pressure on the blades will also be determined from the blade local lift to estimate the turbine noise footprint and compared with experimental data from wind tunnel tests with a scaled turbine instrumented with strain gauges. The final objective of the project will be to develop "smart" control systems to minimize the high vibration problems detected with earlier installations of the Darrieurs rotor.

将对单独的 Darrieus 型垂直轴风力涡轮机 (VAWT) 以及在风电场中的气动弹性和气动声学行为进行研究。 Darrieus 风力涡轮机在 20 世纪 70 年代很常见，但由于振动过大的问题而被淘汰。 “智能”控制系统和抑制振动的叶片桨距控制以及复合材料叶片结构的出现使这一概念设计焕发了活力。此外，在更深的水域建造海上风电场的必要性。最大限度地减少人口稠密地区附近不可避免的视觉和噪音污染，促使业界考虑使用浮动式风力涡轮机。由于其固有的稳定性问题，水平轴风力涡轮机不适合浮动装置。******“troposkien”（来自希腊语“旋转绳索”）几何形状最大限度地减少了 Darrieus 叶片的疲劳。考虑到结构引起的非线性效应，将研究“troposkien”叶片在非定常空气动力学作用下的结构动态行为。叶片的曲率和叶片方位角区域中存在的气动动态失速结构动力学将以状态向量混合公式形式表示，其中面内和面外方向上的力和位移将被考虑为VAWT 的空气动力学模拟将结合自由尾流涡流模型进行开发，其中每个叶片部分都会由于叶片升力随时间的变化而产生涡流（细丝）。为了获得更好的效果，将通过相邻涡旋的涡度和风自由速度引起的速度场，让其在流动的拉格朗日描述中在空间中演化。这种数值方法在计算上可以有效地表示旋转机翼中的自由尾流，因为它是无混杂的，并且对于传统中通常遇到的涡流强度的不切实际的数值耗散具有鲁棒性。 （基于网格的）计算流体动力学方法将上述结构模型和空气动力学模型耦合起来，包括自激（颤振和极限循环振荡）以及由于非定常动态和空气动力载荷而导致的结构气动弹性受迫响应。还将通过叶片局部升力确定叶片上不稳定声压产生的气动声发射，以估计涡轮机噪声足迹，并与风洞测试的实验数据进行比较。配备应变仪的缩放涡轮机。该项目的最终目标是开发“智能”控制系统，以最大限度地减少早期安装 Darrieurs 转子时检测到的高振动问题。