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ENHANCING AEROMECHANICAL ANALYSIS AND DESIGN CAPABILITIES OF WIND TURBINE ROTORS BY MEANS OF NONLINEAR FREQUENCY-DOMAIN COMPUTATIONAL FLUID DYNAMICS

利用非线性频域计算流体动力学增强风力发电机转子的航空机械分析和设计能力

基本信息

批准号：
EP/F038542/1
负责人：
Michele Sergio Campobasso
金额：
$ 38.49万
依托单位：
University of Glasgow
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2008
资助国家：
英国
起止时间：
2008 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FF038542%2F1
关键词：
ENHANCING AEROMECHANICAL ANALYSIS DESIGN CAPABILITIES

项目摘要

Among technically and economically viable renewable energy sources, wind power is that which exploitation has been growing fastest in the recent years. This research focuses on modern Horizontal Axis Wind Turbines (HAWT's), which typically feature two- or three-blade rotors. The span of HAWT blades can vary from a few meters to more than 100 meters, and their design is a complex multidisciplinary task which requires consideration of strong unsteady interactions of aerodynamic and structural forces. Some of the most dangerous sources of aerodynamic unsteadiness are a) yawed wind, due to temporary non-orthogonality of wind and rotor plane, and b) blade dynamic stall. These phenomena result in the blades experiencing time-varying aerodynamic forces, which can excite undesired structural vibrations. This occurrence, in turn, can dramatically reduce the fatigue life of the blades and their supporting structure, yielding premature mechanical failures. Events of this kind can compromise the technical and financial success of the installation, which heavily relies on fulfilling the expectations of minimal servicing on time-scales of the order of 10 to 30 years. These facts highlight the importance of the aeroelastic design process of HAWT blades. The unsteady aerodynamic loads required to determine the structural response must be understood and accurately quantified in the development phase of the turbine. Due to the sizes at stake, in most cases it is infeasible to perform aeroelastic testing, not only from an economic but also logistic viewpoint. Hence these aeroelastic issues can only be tackled by using accurate simulation tools.The general motivation of this project is two-fold: it aims both at enriching the knowledge of unsteady flows relevant to wind turbine aeroelasticity, and advancing the state-of-the-art of the computational technology to accomplish this task. These objectives are pursued by using a novel Computational Fluid Dynamics (CFD) approach to wind turbine unsteady aerodynamics. The unsteady periodic flow relevant to aeroelastic analyses is determined by solving the three-dimensional unsteady viscous flow equations with the nonlinear frequency-domain (NLFD) technology. The NLFD-CFD approach has been successfully applied to fixed-wing and turbomachinery aeroelasticity. This research will exploit this high-fidelity methodology to enhance the understanding of the severe unsteady aerodynamic forcing of HAWT blades, and substantially reduce computational costs with respect to conventional time-domain CFD analyses. This method is particularly well suited to investigate the unsteady aerodynamic blade loads associated with stall-induced vibrations and yawed wind. On the other hand, this technology will greatly help designers to develop new blades without relying on the database of existing airfoil data on which the majority of present analysis and design systems depend. One of the main results of this project will be to greatly reduce the dichotomy between the conflicting requirements of physical accuracy and computational affordability of the three-dimensional unsteady viscous flow models for wind turbine unsteady aerodynamics and aeroelasticity. The achievements of this research will benefit the British and European industry in that they will offer an effective tool to design more efficient and reliable blades. The NLFD-CFD technology will also provide deeper insight into unsteady aerodynamic phenomena which affect the fatigue life of wind turbines. In the next few years, the certification process of wind turbines will enforce stricter requirements on the industry. The developed technology will support the analyses required to meet enhanced certification standards. The Unsteady Aerodynamics Research Community as a whole will also benefit from this research, because its findings will enhance and consolidate the deployment of the NLFD technology in rotorcraft, turbomachinery, and aircraft aeroelasticity.

在技术上和经济上可行的可再生能源中，风能是近年来开发增长最快的能源。本研究的重点是现代水平轴风力涡轮机（HAWT），通常具有两个或三个叶片转子。HAWT叶片的跨度可以从几米到100多米不等，其设计是一项复杂的多学科任务，需要考虑空气动力和结构力的强烈非定常相互作用。空气动力学不稳定性的一些最危险的来源是a）偏航风，由于风和转子平面的暂时非正交性，和B）叶片动态失速。这些现象导致叶片经受随时间变化的空气动力，这可能激发不期望的结构振动。这种情况的发生又会显著降低叶片及其支撑结构的疲劳寿命，导致过早的机械故障。这类事件可能会损害装置的技术和财政成功，因为装置在很大程度上依赖于在10至30年的时间范围内实现最低限度服务的期望。这些事实凸显了HAWT叶片气动弹性设计过程的重要性。在涡轮机的开发阶段，必须了解并准确量化确定结构响应所需的非定常气动载荷。由于所涉及的尺寸，在大多数情况下，不仅从经济角度而且从物流角度来看，进行气动弹性试验是不可行的。因此，这些气动弹性问题只能通过使用精确的仿真工具来解决。本项目的总体动机是双重的：它旨在丰富与风力涡轮机气动弹性相关的非定常流的知识，并推进最先进的计算技术来完成这一任务。这些目标是追求通过使用一种新的计算流体动力学（CFD）的方法，风力涡轮机非定常空气动力学。采用非线性频域（NLFD）技术求解三维非定常粘性流动方程，确定与气动弹性分析相关的非定常周期流动。NLFD-CFD方法已成功地应用于固定翼和机翼气动弹性。本研究将利用这种高保真度的方法，以提高对HAWT叶片的严重非定常气动力的理解，并大大降低计算成本，相对于传统的时域CFD分析。该方法特别适合于研究与失速诱导振动和偏航风相关的非定常气动叶片载荷。另一方面，该技术将极大地帮助设计人员开发新的叶片，而不依赖于现有的翼型数据库，大多数目前的分析和设计系统所依赖的。该项目的主要成果之一是大大减少风力涡轮机非定常空气动力学和气动弹性的三维非定常粘性流模型的物理精度和计算承受能力之间的矛盾。这项研究的成果将有利于英国和欧洲的工业，因为他们将提供一个有效的工具，设计更有效和可靠的叶片。NLFD-CFD技术还将为影响风力涡轮机疲劳寿命的非定常空气动力学现象提供更深入的见解。未来几年，风力涡轮机的认证过程将对行业提出更严格的要求。所开发的技术将支持满足强化认证标准所需的分析。整个非定常空气动力学研究界也将从这项研究中受益，因为其研究结果将增强和巩固NLFD技术在旋翼机、旋翼机和飞机气动弹性中的部署。