风力机尾缘襟翼气动特性与机理研究_李传峰.docx

《风力机尾缘襟翼气动特性与机理研究_李传峰.docx》由会员分享，可在线阅读，更多相关《风力机尾缘襟翼气动特性与机理研究_李传峰.docx（73页珍藏版）》请在淘文阁 - 分享文档赚钱的网站上搜索。

1、 中国科学院大学 University of Chinese Academy of Sciences 博士学位论文 风力机尾缘襟翼气动特性与机理研究 作者姓名 ： _ 李传峰 _ 指导教师： 徐建中研究员 中国科学院工程热物理研究所 徐宇副研究员 中国科学院工程热物理研究所 学位类别： _ 1：学愤 + _ 学科专业： _ 工程热物理 _ 培养单位： _ 中国科学院工程热物理研究所 _ 二零一三年三月 Study on Aerodynamic Performance and Mechanism of Trailing Edge Flap on Wind Turbine By Li Chuanf

2、eng A Dissertation Submitted to University of Chinese Academy of Sciences In partial fulfUlment of the requirement For the degree of Doctor of Engineering Institute of Engineering Thermophysics Chinese Academy of Sciences March, 2013 关于学位论文使用权声明 任何收存和保管本论文各种版本的单位和个人，未经著作权人授权，不得 将本论文转借他人并复印、抄录、拍照、或以任

3、何方式传播。否则，引起有碍 著作权人著作权益之问题，将可能承担法律责任。 关于学位论文使用授权的说明 本人完全了解中国科学院工程热物理研宄所有关保存、使用学位论文的规 定，即：中国科学院工程热物理研究所有权保留学位论文的副本，允许该论文 被查阅；中国科学院工程热物理研宄所可以公布该论文的全部或部分内容，可 以采用影印、缩印或其他复制手段保存该论文。 (涉密的学位论文在解密后应遵守此规定 ） 签 名 :李传 4 导师签名： 日期：分 .2/ 关于学位论文原创性声明 本人郑重声明：所呈交的学位论文是本人在导师指导下，独立进行研宄工 作所取得的成果。尽我所知，除文中己经注明引用的内容外，本学位论文的

4、研 宄成果不包含任何他人享有著作权的内容。对本论文所涉及的研宄工作做出贡 献的其他个人和集体，均已在文中以明确方式标明。 签 名 ： 杳 率 导 师 签 名 ： 曰 期 ： 加 令 今 、 w 随着风力机额定功率和叶片尺寸的增加，风力发电系统成本増加，降低成本成为风电 发展中的一个重要问题。叶片是风力机的核心部件，降低叶片载荷，相关的其他部件的载 荷也会降低，从而降低 了对这些部件的要求，有效降低整体成本。尾缘襟翼被认为是风力 机载荷控制方法中最具可行性的气动控制部件。本文采用定常和非定常计算流体力学方法 研究了尾缘襟翼在二维风力机翼型和三维风力机叶片上的气动特性，分析尾缘襟翼对流场 结构的影

5、响和尾缘襟翼作用机理，通过尾缘襟翼调节可以降低变化来流引起的载荷变化幅 度，从而降低疲劳载荷，为尾缘襟翼实际应用和控制规律的优化提供一定的参考，为动量 叶素理论针对尾缘襟翼及其它控制部件模拟的修正提供了依据和方向。计算流体力学模拟 中，采用带有转捩模型的四方程 Transition SST模型，并应用动网格方法实现尾缘襟翼运 动时网格的更新。 首先，对二维风力机 S809翼型和三维 NREL Phase VI叶片进行了数值模拟，验证了 所采用计算模型的有效性。攻角较小时，二维翼型升力系数与实验结果偏差小于 3%，阻 力系数偏差小于 10%,比全湍流模型大于 100%的阻力系数偏差有较大改善。三

6、维叶片模 拟中低速轴转矩与实验偏差在 4%以下，优于全湍流模型在部分分离情况下 24%的偏差。 模拟的层流分离泡和转捩点的位置与实验结果也较为接近。 接着，研究了二维翼型尾缘襟翼相关问题： 1) 通过对静态尾缘襟翼的分析，获得尾缘襟翼优化参数及并定量分析了其改变翼型 气动参数的能力。结果表明，在考察参数范围内， 10%弦长可连续变形弹性尾缘襟翼、偏 转角度 10 左右、形状函数为 1次幂函数时综合性能较好，既能取得较大的升力系数变化， 而阻力系数和尾缘襟翼较矩系数变化较小，且流场较为稳定。具有上述优化参数的尾缘襟 翼，在攻角和偏转角度较小时，来流攻角变化引起的升力系数变化，需要尾缘襟翼偏转角

7、度变化 2.44倍来抵消。 2) 疲劳载荷的降低，通过尾缘襟翼的运动来实现，分析运动尾缘襟翼特性，有利于 在驱动尾缘襟翼时 ，根据实际来流和尾缘襟翼状态适当调整控制规律。研宄了定常来流下， 尾缘襟翼偏转角频率、偏转角度幅值、襟翼长度、来流攻角、偏转中心角度、偏转规律等 对运动尾缘襟翼气动特性的影响。在翼型附近没有较大流动分离时，升力系数滞后于偏转 角度变化，存在相位差，且随着尾缘襟翼偏转角频率增大，相位差先增大后减小，随着偏 转角度幅值、襟翼长度和来流攻角增大，相位差均有所减小。尾缘襟翼不在最大偏转角度 附近时，升力系数随偏转角度近似成线性变化，随着角频率减小，偏转角度幅值和襟翼长 度增大，斜

8、率绝对值有所增大，表明尾缘襟翼改变升 力系数能力增大。 研宄运动尾缘襟翼特性时，确定以尾缘襟翼长度为特征尺度表征的折合频率作为特征 风力机尾缘襟翼气动特性与机理研宄 参数评价所考察问题的非定常特性。当该折合频率大于或接近 0.01时，流场具有明显的非 定常特性，尾迹涡量开始出现弯曲和卷起趋势，并随着折合频率进一步增大，出现周期性 涡脱落现象。折合频率较小时，流动可视为准定常的，尾迹涡量与定常计算结果较为接近。 3) 利用具有优化参数的尾缘襟翼，并根据动态尾缘襟翼分析结果适当调整相位，分 析了尾缘襟翼对正弦变化来流下二维翼型的作用效果。通过与来流相同频率和相同相位运 动的10%弦长尾缘襟翼的作用

9、，法向力系数变化幅度减小约 90%;添加适当的相位差后， 法向力系数变化幅度减小约 93%，且随时间变化趋势更为平缓。尾缘襟翼对整个翼型表面 压力系数均有较大影响，而不局限于尾缘襟翼所在弦向位置。 最后，在二维翼型尾缘襟翼分析基础上，研究了尾缘襟翼在三维风力机叶片上的气动 特性。来流垂直于风轮平面、大小按正弦规律变化时，通过相同频率运动尾缘襟翼的作用， 叶片挥舞方向叶根弯矩变化幅度减小了 27% 38%， 叶片表面流动状态不同时，尾缘襟翼 效果不同，添加适当的相位差，降载幅度有所提高，且力矩曲线随时间变化趋势略微平缓。 尾缘襟翼能够减小变化来流引起的载荷变化幅度，显示了尾缘襟翼降低疲劳载荷的能

10、力。 尾缘襟翼对于风力机叶片的影响不局限于尾缘襟翼所在展向位置。尾缘襟翼从原始叶片位 置偏向的一侧压力增大，流线由尾缘襟翼中心沿展向向两侧偏斜，另一侧变化恰好相反。 由于流体的连续性，尾缘襟翼所在位置压力变化，临近位置压力也会发生类似趋势的变化。 尾缘襟翼对气动参数的影响，在尾缘襟翼所在展向位置最大，随着与尾缘襟翼距离增 大， 影响有所减小，但几乎整个叶片表面均受到尾缘襟翼影响。 关键词：风力机，尾缘襟翼，气动特性，计算流体力学 n Abstract Abstract With the rated power of wind turbines and the size of blades in

11、creasing, cost of wind electricity system increases a lot, so reducing the cost is an important issue to promote wind electricity development. The blade is a key component of wind turbines. Decreases of blade loads will result in decreases of loads of other related components, and then substantial s

12、avings may be realized to reduce the total cost. The trailing edge flap is considered to be one of the most effective active control methods. Steady and unsteady computational fluid dynamics methods are adopted in this paper to study the aerodynamic performances of a two dimensional wind turbine air

13、foil and a three dimensional wind turbine blade. Influences of trailing edge flaps on fluid structures and mechanism of trailing edge flaps are investigated. The flap could reduce the loads fluctuation resulting from wind variation, and then fatigue loads are reduced. The results may help to promote

14、 the engineering use of trailing edge flaps and provide a direction of adjustments of flap control methods and modifications of blade element momentum methods for study of trailing edge flaps. Four equations Transition SST model including a transition model is adopted to model the turbulence, and th

15、e dynamic mesh method is used to evaluate the grids as trailing edge flaps deflect. First, the two dimensional S809 airfoil and three dimensional NREL Phase VI blade are simulated to verify the validation of the model. It indicates that the Transition SST model is more accurate than fully turbulent

16、models. For small angles of attack, compared with the experimental results, the predicted lift coefficients of S809 airfoil are accurate to within 3% and the drag coefficients to within 10%, but the drag coefficients predicted by fully turbulent models are larger than measurements by as much as 100%

17、. For the NREL Phase VI rotor, the predicted low speed shaft torques are accurate to within 4%, more accurate than fully turbulent models whose error is about 24% under partial separation conditions. Moreover, the predicted locations of laminar separation bubbles and transition points are very close

18、 to experimental results. Next, related issues of the trailing edge flap on a two dimensional airfoil are investigated: 1) By analyses of the stationary trailing edge flap, the optimal parameters of the flap are obtained and the capacity of the flap to change the aerodynamic parameters of the airfoi

19、l is investigated. The results show that, among the studied parameters, a continuously deforming elastic trailing edge flap with 10% chord length, 10 flap angle and a shape function of one order power function obtains better results which mean large enough lift coefficients variations and fairly low

20、 drag coefficients and hinge moment coefficients variations as well as a stable flow in 风力机尾缘襟翼气动特性与机理研究 field. When the angles of attack are not too big, the angles of trailing edge flap should be 2.44 times those of angles of attack to obtain the same variations of lift coefficients. 2) Reduction

21、of fatigue loads is achieved by oscillation of the trailing edge flap, so analyses of the dynamic properties of the trailing edge flap will help modify the control strategies according to properties of inflows and the trailing edge flap. Under constant inflows, influences of certain parameters, such

22、 as angular frequencies, amplitudes of deflection angles, lengths of the flaps, angles of attack, mean angles of deflection angles, et al., on the oscillating trailing edge flaps are investigated. When no obvious separations are observed, the lift coefficients lag the deflection angles and the phase

23、 differences will influence the effect of the trailing edge flap. The phase difference first increases with the angular frequency, and then decreases. Moreover, the phase difference decreases when the amplitude of deflection angles, length of the flap and angle of attack increase. If the trailing ed

24、ge flap does not locate at its maximum or minimum angles, the lift coefficient varies linearly with the deflection angle. When the angular frequency decreases, as well as amplitude of deflection angles and length of flap increase, the absolute value of the slop increases, which indicates that the ca

25、pacity of the flap alternating lift coefficients increases. During simulations of the oscillating trailing edge flap under constant inflows, the unsteady level can be described by the reduced frequency which takes the length of the flap as the characteristic length. When the value of the flap reduce

26、d frequency is greater than or close to 0.01, the flow field appears obvious unsteady characteristic and the wake vorticity appears the trend of bend and rolling up. When the reduced frequency is big enough, periodic vortex shedding shows up. If the reduced frequency is fairly small, the flow could

27、be considered as quasi-steady, and the wake vorticity is similar to that of the steady condition. 3) With the optimal parameters of the trailing edge flap adopted and the phase angle of the flap modified according to the dynamic analyses, the influence of the trailing edge flap on an airfoil under s

28、inusoidally varying wind is investigated. As the effect of a 10% chord length trailing edge flap movement by the same frequency and phase angle with the wind, the variation of the normal force coefficient is reduced by 90%. With a proper phase difference added to the flap movement, the reduction rat

29、e increases to 93%, and the normal forces vary more smoothly. The trailing edge flap influences pressure almost all over the airfoil surface rather than the finite chordwise region of the flap. Finally, based on results of two dimensional analyses, the aerodynamic properties of the trailing edge fla

30、p on a three dimensional wind turbine blade are investigated. When the wind varies by the sine law, under the impact of an oscillating trailing edge flap, the reduction rate of the root flap bending moments is about 27% 3 80/ according to different cases. With a proper IV Abstract phase difference a

31、dded, the reduction rate increases, and the moment curve is smoother. The flap influences not only the sections with a flap mounted， but also other spanwise regions. When the flap deflects, the pressure near the surface of the deflecting direction increases, and the streamlines deflect towards both

32、sides along spanwise direction from the center of the flap, especially near the junction. Opposite changes appear on the other side of the flap. Considering the continuity of the fluid, when the pressure changes near the trailing edge flap, similar changes appear around the nearby sections. The infl

33、uence of the trailing edge flap is most obvious on the very section where the flap locates, and with the spanwise distance from the flap increasing, the impact decreases. KEY WORDS : Wind turbine, trailing edge flap, aerodynamic performance, computational fluid dynamics v 目录 目录 m . I Abstract .Ill 0

34、 . VII 图 S录 . XI . xvn MiM m . i 1.1研究背景 . i i.i.i中国风资源概述 . 1 1.1.2国内外风电发展概述 . 3 1.1.3风电发展中的大型化趋势及其影响 . 7 1.2风力机控制技术 . 9 1.2.1风力机控制概述 . 9 1.2.2风力机载荷控制 . 10 1.3尾缘襟翼研宄综述 . 11 1.3.1尾缘襟翼应用进展 . 11 1.3.2直升机尾缘襟翼研宄 . 12 1.3.3风力机尾缘襟翼研究 . 13 1.4主要研宄内容 . 22 第 2章数值模拟方法与可靠性验证 . 23 2.1数值模拟方法 . 23 2.1.1控制方程 . 23 2

35、.1.2湍流模型 . 24 2.1.3有壁面约束湍流流动近壁网格处理 . 27 2.1.4动网格方法 . 28 2.2方法有效性验证 . 29 2.2.1二维风力机翼型模拟 . 29 2.2.2三维风力机叶片模拟 . 39 2.3本章 小结 . 52 第 3章带有尾缘襟翼的二维风力机翼型分析 . 55 3.1弓丨胃 . 55 3.2二维翼型刚性尾缘襟翼特性分析 . 55 3.2.1分析模型 . 56 VII _风力机尾缘襟翼气动特性与机理研究 _ 3.2.2计算结果及分析 . 56 3.2.3 小结 . 58 3.3二维翼型尾缘襟翼优化参数分析 . 60 3.3.1 弓 | 言 . 60 3.

36、3.2分析模型 . 63 3.3.3 0 攻角正交设计计算结果及分析 . 64 3.3.4 4 攻角下正交设计结果分析 . 69 3.3.5考虑交互作用的正交设计分析 . 70 3.3.6 小结 . 78 3.4二维翼型固定偏转角度尾缘襟翼分析 . 78 3.4.1 引言 . 78 3.42计算模型 . 79 3.4.3 CFD模拟结果分析 . 79 3.4.4薄翼理论分析及结果对比 . 83 3.4.5 小结 . 86 3.5二维翼型运动尾缘襟翼研宄 . 86 3.5.1计算模型 . 87 3.S.2尾缘襟翼偏转角频率对尾缘襟翼动态性能的影响 . 88 3.5.3尾缘襟翼偏转角度幅值对尾缘襟

37、翼动态性能的影响 . 106 3.5.4尾缘襟翼长度对尾缘襟翼动态性能的影响 . 112 3.5.5来流攻角对尾缘襟翼动态性能的影响 . 118 3.5.6偏转中心角度对尾缘襟翼动态性能的影响 . 123 3.5.7偏转规律对尾缘襟翼动态性能的影响 . 129 3.5.8 顿 . 132 3.6二维翼型尾缘襟翼作用效果 . 133 3.6.1计算模型 . 133 3.6,2结果分析 . 133 3.6.3 小结 . 141 3.7本章小结 . 141 第 4章带有尾缘襟翼的三维风力机叶片分析 . 145 4.1弓丨胃 . 145 4.2分析模型 . 145 4.3定常来流下运动尾缘襟翼分析 . 146 4.3.1挥舞方向叶根弯矩结果 . 147 4.3.2压力系数结果 . 147 VIII 目录 4.3.3法向力系数结果 . 153 4.3.4压力云图与极限流线结果 .