水平轴风力机三维气动特性实验

以国外某公司的水平轴风力机产品为原型设计模型风力机，并搭建了风洞实验台，测定了风力机三维速度流场，为研究水平轴风力机关键气动问题做好准备，并初步获得风力机的进出口流场的实验数据。表明，所做的风洞实验基本反映了风力机的运行特点，捕捉到了叶片尾迹流动的基本特征，为进一步进行风力机的气动特性研究和设计高性能的水平轴风力机提供了保障。     

垂直轴风力机的现在和未来

本文主要介绍小型垂直轴风力机的类型,各类小型垂直轴风力机的优缺点、小型垂直轴风力机的设计思想,以及小型垂直轴风力机主要设计参数的关联性和未来垂直轴风力机的发展方向,也简要介绍了磁悬浮在垂直轴风力机中的应用状态。     

水平轴风力机轮毂强度和疲劳寿命分析方法研究

针对水平轴风力机轮毂复杂的几何外形、载荷与边界条件,研究其强度和疲劳寿命数值分析方法。应用结构分析软件ANSYS并结合疲劳分析软件FE-safe对风力机轮毂进行强度和多轴疲劳寿命分析。研究了风力机轮毂结构强度数值分析中的一些关键技术问题,如网格划分、载荷施加、边界约束条件的处理及分析技巧等;利用叶片根部极限载荷对轮毂进行强度校核,得出轮毂极限载荷下的应力分布。基于风力机叶片根部随机载荷谱和线性累积损伤方法,研究了轮毂多轴疲劳特性及疲劳寿命分析方法;研究了轮毂材料的S-N曲线定义和各工况下随机载荷谱的分析处理方法。算例表明:本文的工作为水平轴风力机轮毂强度、刚度及多轴疲劳寿命分析等提供了实用的分析方法。     

小型风力机大风限速方法的发展与研究现状

总结了小型风力机常用的大风限速方法的发展与研究现状,介绍了具有风轮侧偏机构的风力机和被动变桨矩风力机的结构动力学的研究进展,以及尾舵空气动力学和结构动力学的研究现状.     

偏航工况下水平轴风力机叶片气动变形数值模拟研究

以非定常叶素动量方法和水平轴风力机结构动力学为基础,建立风力机气弹计算的仿真程序,将偏航模型耦合进气弹程序中,针对某5 MW水平轴风力机进行仿真计算,分析比较了该风力机在不同偏航角工况下叶片变形沿径向和周向的分布情况,总结了不同偏航工况对风力机叶片变形的影响规律。研究结果对风力机叶片设计和疲劳寿命的预测有一定的指导意义。     

基于压力表示法的水平轴风力机风轮气动弹性稳定性模型及应用

该文对影响水平轴风力机气动弹性稳定性的物理机理进行了分析，对国内外的研究方法进行了阐述。建立了基于压力表示法的水平轴风力机风轮气动弹性稳定性敏感性分析方法的物理与数学模型，综合考虑了风力机风轮的气动与结构参数对气动弹性稳定的影响。以600kw水平轴风力机风轮为例，对其气动弹性稳定性进行了分析与研究，获得了该风力机的气动弹性稳定性裕度和工作范围。考虑到风力机三维流动、风轮与塔架的藕合以及来流湍流和阵风等来流工况的复杂性，该分析模型目前还没有将上述因素考虑在内。若均考虑在内，则其能够提供较高的气动弹性稳定性预测精度。     

RESEARCH ON ANALYSIS APPROACH OF STRENGTH AND FATIGUE LIFE OF HORIZONTAL AXIS WIND TURBINE HUB

针对水平轴风力机轮毂复杂的几何外形、载荷与边界条件,研究其强度和疲劳寿命数值分析方法.应用结构分析软件ANSYS并结合疲劳分析软件FE-safe对风力机轮毂进行强度和多轴疲劳寿命分析.研究了风力机轮毂结构强度数值分析中的一些关键技术问题,如网格划分、载荷施加、边界约束条件的处理及分析技巧等;利用叶片根部极限载荷对轮毂进行强度校核,得出轮毂极限载荷下的应力分布.基于风力机叶片根部随机载荷谱和线性累积损伤方法,研究了轮毂多轴疲劳特性及疲劳寿命分析方法;研究了轮毂材料的S-N曲线定义和各工况下随机载荷谱的分析处理方法.算例表明:本文的工作为水平轴风力机轮毂强度、刚度及多轴疲劳寿命分析等提供了实用的分析方法.     

水平轴风力机的气动数值模拟

对某型号的国家大型水平轴风力机进行了空气动力学模拟仿真研究,给出了该型号风力机的流场模拟仿真的原理和一般性步骤.以低速自由来流为条件,得到了该型号风力机的整体气动性能模拟结果.在数值模拟基础上,对整机压力、速度分布以及尾涡的形成进行了具体分析讨论.     

垂直轴风力机概述及发展优势剖析

本文简要介绍了垂直轴风力机的各种类型及其原理特点,然后对垂直轴风力机与水平轴风力机在结构设计、空气动力学性能、环境的影响等多方面进行了比较,体现了垂直轴风力机的独有优势,并得出垂直轴风力机发展前景广阔的结论。     

垂直轴风力机技术讲座(三) 升力型垂直轴风力机

1 升力型垂直轴风力机概述 近30年来,螺旋桨式水平轴风力机发展迅速,已成为大型商业风力发电的主流.与此同时,以达里厄风力机为代表的升力型垂直轴风力机也受到一些风电发达国家的关注.虽然垂直轴风力机没有像水平轴风力机那样快速发展,但也取得了一定的进展.     

The relationship between chord length and rime icing on wind turbines

Numerical simulations of ice accumulation on four different wind turbine blade profiles, from 450 kW, 600 kW, 1 MW and 2 MW, fixed speed, stall controlled, wind turbines, were performed to determine how wind turbine size affects atmospheric icing. The simulations indicate that dry rime icing is less severe for larger wind turbines both in terms of local ice mass and in terms of relative ice thickness. Copyright © 2009 John Wiley & Sons, Ltd.     

基于BEDDOES-LEISHMAN动态失速模型的水平轴风力机动态气动载荷计算方法

从对附着流和分离流的建模两方面阐述了Beddoes-Leishman动态失速模型.基于Beddoes-Leishman模型开发了动态失速数值计算程序,并将其集成到了现有的风力机气动载荷分析软件中.利用所开发的程序,计算了NACA 63-418翼型的动态失速特性,分析了平均攻角、衰减频率和马赫数的变化对动态失速特性的影响.仿真了一台1.5MW变速恒频风电机组的发电工况,结果表明,动态失速对风力机的动态气动载荷有极大影响,在进行动态载荷仿真时必须予以充分考虑.     

考虑动态失速与风轮支架损失的H型垂直轴风力机自由尾迹模型构建

采用基于升力线理论的自由尾迹模拟模型,耦合了Leishman-Beddoes（LB）动态失速模型和模拟支架损失的半经验公式,编制H型垂直轴风轮计算程序,对不同直径、不同实度的风轮进行气动性能模拟。为了检测模型对H型风轮输出计算的准确性,选取2种不同实度（分别为0.13和0.48）的H型风力机进行了对比分析。结果表明,当尖速比小于4时,动态失速影响较为明显。考虑支架损失的计算结果明显优于未考虑支架损失的计算结果,支架损失总体上随尖速比的增大而增大,2台风力机对应的最大支架损失分别高达60%和35.5%。考虑动态失速效应和支架损失的计算模型能较为准确地估算风轮实度较小的H型风轮的输出,但对于实度较大的H型风轮,其计算准确度有待进一步提高。     

Aeroelastic instability problems for wind turbines

This paper deals with the aeroelastic instabilities that have occurred and may still occur for modern commercial wind turbines: stall‐induced vibrations for stall‐turbines, and classical flutter for pitch‐regulated turbines. A review of previous works is combined with derivations of analytical stability limits for typical blade sections that show the fundamental mechanisms of these instabilities. The risk of stall‐induced vibrations is mainly related to blade airfoil characteristics, effective direction of blade vibrations and structural damping; whereas the blade tip speed, torsional blade stiffness and chordwise position of the center of gravity along the blades are the main parameters for flutter. These instability characteristics are exemplified by aeroelastic stability analyses of different wind turbines. The review of each aeroelastic instability ends with a list of current research issues that represent unsolved aeroelastic instability problems for wind turbines. Copyright © 2007 John Wiley & Sons, Ltd.     

New vortex‐lift and tangential‐force models for HAWT aerodynamic load prediction

Horizontal axis wind turbines (HAWTs) experience three‐dimensional rotational and unsteady aerodynamic phenomena at the rotor blades sections. These highly unsteady three‐dimensional effects have a dramatic impact on the aerodynamic load distributions on the blades, in particular, when they occur at high angles of attack due to stall delay and dynamic stall. Unfortunately, there is no complete understanding of the flow physics yet at these unsteady 3D flow conditions, and hence, the existing published theoretical models are often incapable of modelling the impact on the turbine response realistically. The purpose of this paper is to provide an insight on the combined influence of the stall delay and dynamic stall on the blade load history of wind turbines in controlled and uncontrolled conditions. New dynamic stall vortex and nonlinear tangential force coefficient modules, which integrally take into account the three dimensional rotational effect, are also proposed in this paper. This module along with the unsteady influence of turbulent wind speed and tower shadow is implemented in a blade element momentum (BEM) model to estimate the aerodynamic loads on a rotating blade more accurately. This work presents an important step to help modelling the combined influence of the stall delay and dynamic stall on the load history of the rotating wind turbine blades which is vital to have lighter turbine blades and improved wind turbine design systems.     

Grid support of a wind farm with active stall wind turbines and AC grid connection

One of the main concerns in the grid integration of large wind farms is their ability to behave as active controllable components in the power system. This article presents the design of a new integrated power control system for a wind farm made up exclusively of active stall wind turbines with AC grid connection. The designed control system has the task of enabling such a wind farm to provide the best grid support. It is based on two control levels: a supervisory control level, which controls the power production of the whole farm by sending out reference signals to each individual wind turbine, and a local control level, which ensures that the reference power signals at the wind turbine level are reached. The ability of active stall wind farms with AC grid connection to control the power production to the reference power ordered by the operators is assessed and discussed by means of simulations. Copyright © 2005 John Wiley & Sons, Ltd.     

大型失速型风力发电机动态特性研究

通过分析主动失速型机组的来流风速、气动、机械传动与发电机等部件的机理,建立了机组各主要部件的子系统模型(如气动模型、传动模型、发电机暂态模型、补偿电容模型、电网模型和控制系统模型等),近而得到了全系统的动态非线性模型。通过对机组全系统动态机理模型的数字仿真,得到机组在特定来流工况条件下的动态特性。所建立的模型和仿真结果为今后研究风电场与电网之间的相互影响提供了理论基础。     

Behaviour improvement during faults of fixed speed stall control induction generator wind turbines

This paper describes a simple and economical way to improve the behaviour of a stall control wind turbine with fixed speed induction generator during faults. It proposes using the existing thyristor bridge and capacitors in combination with new resistors, to create a self‐exciting system isolated from the grid during faults, controlling the terminal voltage and speed generator in order to reduce the reactive consumption and peak speed. This is possible as a result of the thyristor bridge and resistor acting as a variable load. Dynamic simulations show that fault ride‐through capability for symmetrical and asymmetrical faults of a stall wind turbine can be achieved by using this proposal. A comparison between this solution and the standard static compensator solution demonstrates that the proposed solution works better, mainly because of the absence of overspeed problems when the overspeed protection is set at around 1.04 p.u. (a typical level for these wind turbines). Copyright © 2008 John Wiley & Sons, Ltd.     

基于复合形法的垂直轴风力机翼型优化设计

针对低速航空翼型不完全适合垂直轴风力机的问题,采用复合形法对小型垂直轴风力机常用的NACA0015翼型进行了优化设计。在复合形法优化设计过程中,选取翼型的弯度和厚度作为设计变量,以翼型最大切向力系数Ctmax和失速攻角αs的加权和作为目标函数。将XFOIL程序与Viterna-Corrignan失速后模型相结合,计算出优化前后翼型气动性能参数。结果表明,与NACAOO15翼型相比,新翼型的气动性能有了较大提高,最大升力系数增大了33.5%,失速攻角提高了3°,最大切向力系数增大了43.5%。     

Digital tuft analysis of stall on operational wind turbines

Operational wind turbines are exposed to dynamic inflow conditions because of, for instance, atmospheric turbulence and wind shear. In order to understand the resulting three‐dimensional and transient aerodynamics effects at a site, a 10m stall‐regulated upwind two‐bladed wind turbine was instrumented for a novel digital tuft flow visualization study. High definition video of a tufted blade was acquired during wind turbine operation in the field, and a novel digital image processing algorithm calculated the blade stall directly from the video. After processing O(10⁵) sequential images, the algorithm achieved a ?5% bias error compared with previous manual analysis methods. With increasing wind speed (5m/s to 20m/s) the fraction of tufts exhibiting stalled flow increased from 5% to 40% on the outboard 40% of the blade. The independently measured instantaneous turbine power production correlates highly with the stall fraction. Some azimuthal variation in the stall fraction associated with dynamic stall induced by vertical wind shear was seen with a maximum in the 45–90° azimuthal location. The high detail, quantitative image processing method demonstrated good agreement with the expected behaviour for a stall‐regulated wind turbine and revealed azimuthal variation because of shear‐induced dynamic stall. The amount of reliable blade stall data to be obtained from digital tuft visualization has hereby been vastly increased. Copyright © 2015 John Wiley & Sons, Ltd.