【作者】 汪泉；

【导师】 陈进；

【作者基本信息】 重庆大学 ， 机械设计及理论， 2013， 博士

【摘要】 风能作为一种清洁的可再生能源，越来越受到世界各国的关注与重视。预计未来20～25年内，世界风电市场每年将递增25%。随着国家对风力发电的重视，风力机近年来得到了广泛的应用和发展。而叶片是风力机最关键的部件之一，达到整机价值的20%左右，其良好的设计、可靠的质量和优越的性能是保证机组正常稳定运行的决定因素。在国家自然科学基金项目“基于参数化的风力机叶片气动性能与结构一体化设计理论（项目编号：51175526）”和国家高技术研究发展计划(863计划)“先进风力机翼型族设计技术研究（项目编号：2012AA051301）”的资助下，本文提出了“风力机叶片气动外形与结构的参数化耦合设计理论研究”的研究课题。在分析国内外风力机翼型、叶片及结构与气动弹性研究理论方法的基础上，针对集成现有翼型的基础上，对风力机翼型泛函集成理论进行了深入的研究，提出一种基于翼型表面曲率光滑连续性思想的翼型改进设计方法；针对中等厚度及大厚度翼型，提出一种新的翼型参数化表征方法，即翼型集成理论与B样条结合的翼型集成表达方式，结合改进的粒子群算法，充分考虑风力机翼型及叶片的空气动力性能要求，设计得到性能优良的7种不同厚度的标准翼型（相对厚度从15%～40%）；提出了基于叶片性能与轻量化的风力机叶片设计方法，并在叶片全部产生功率区域内采用笔者设计的7种标准翼型进行叶片气动外形优化，优化得到了高性能轻质量的风力机新型叶片；提出了将翼型数据、叶片外形参数及复合材料叶片结构参数集成于叶片可变参数化解析表示式中，建立了叶片参数化有限元模型，结合粒子群算法，对风力机叶片结构在气动载荷作用工况下进行了优化，其优化结果显著。从而形成了风力机翼型、叶片及结构自主设计的新理论和新方法，使风力机叶片形状与叶片弹性变形耦合设计成为可能。论文完成的主要研究工作和取得的研究成果主要有：1）探讨了翼型几何参数、气动参数对翼型气动性能的影响关系。对计算翼型气动性能的计算方法进行了研究。针对三种不同厚度的风力机专用翼型WT180（该翼型为本课题组研发的一种高性能风力机专用翼型）、DU93-W-210和DU91-W2-250，在相同计算工况条件下，将RFOIL软件所计算出来的气动结果与实验数据结果进行了对比分析，研究表明RFOIL软件能够较好的预测翼型的气动性能，适用于翼型的直接设计方法，同时为后文新翼型族的研发提供有效的气动性能计算工具。2）为了便于优化出性能较高的风力机翼型，依据目前常用的翼型优化算法，继而引入粒子群算法，对比了粒子群算法与其他生物进化算法的优缺点，为了克服粒子群算法在优化初期容易陷入局部最优解的缺点，提出了一种具有反双曲余弦函数形式的非线性惯性权重表示法，用以改善标准的粒子群算法的性能，并对此改进的粒子群算法进行了实例分析。分析结果表明，无论是在寻优能力方面，还是在计算稳定性方面，改进的粒子群算法都要优于标准的粒子群算法，从而验证了该改进算法的有效性和可行性。为风力机专用翼型的研发提供了有效的算法基础。3）在现有翼型泛函集成理论的基础上，提出一种基于表面曲率光滑连续性思想的翼型改进与设计方法。对荷兰DU93-W-210翼型进行了改进与优化，研究表明优化后的新翼型在升力系数、升阻比、粗糙度敏感性等气动特性方面要明显优于原翼型。针对不同厚度的风力机翼型而言，采用不同的翼型型线构造方法对风力机专用翼型进行了优化设计研究。针对较薄的风力机翼型族，基于翼型泛函集成设计理论，提出了增加设计变量参数从而有效地控制翼型型线轮廓线的翼型设计策略。综合考虑翼型的前缘粗糙度敏感性、非设计工况特性、失速特性及噪声特性等，采用改进的粒子群算法耦合RFOIL软件对较薄的翼型族进行了优化设计，设计出了3种相对厚度较薄的新翼型，分别为CQU-A150、CQU-A180和CQU-A210翼型；针对中等厚度及大厚度翼型，提出了翼型泛函集成与B样条理论结合的翼型设计新方法，主要考虑翼型的结构与气动特性，采用改进的粒子群算法对中等厚度及大厚度翼型进行优化设计，设计出了4种不同厚度风力机专用翼型，分别为CQU-A250、CQU-A300、CQU-A350和CQU-A400翼型。对这7种翼型进行了详细的气动性能分析，通过与目前常用的风力机翼型的比较分析，能够很好地满足翼型结构与气动性能要求的各项指标，表明这7种翼型具有较好的气动性能与结构兼容性，从而验证了该方法的可行性与优越性。本研究完善了翼型泛函集成设计理论，为风力机专用翼型的设计研究拓宽了思路，同时为风力机叶片气动外形的设计奠定了良好的基础。4）基于风力机空气空力学理论，详细分析研究了叶片关键参数（如叶尖速比、风轮直径、雷诺数、翼型气动性能及叶片载荷等）对风力机性能的影响；进而在整个叶片设计上采用作者全新设计的风力机翼型系列CQU-A，提出以最大功率系数及最小叶片面积为多目标优化模型，以弦长、扭角为设计变量，有效控制叶片载荷以提高叶片疲劳寿命，建立新型风力机叶片设计及优化数学模型。应用该设计模型，采用改进的多目标粒子群算法对风力机叶片进行优化设计，并将优化结果与初始叶片、Tjaere实验叶片进行对比分析。优化结果表明，相比初始叶片及Tjaere型叶片，新设计2MW风力机叶片的最大功率系数及年发电量均有所提高，而且叶片表面面积具有显著的下降，这意味着在其他叶片内部结构不变的情况下极大的减少了叶片的质量，提高了叶片的疲劳寿命，降低了叶片的材料成本；同时叶根载荷也得到了有效的控制。该新型叶片的研究为设计出高性能轻质量低成本的风力机提供了理论依据。5）在复合材料风力机叶片弹性力学的基础上，基于复合材料学等代设计法及机械设计学中的类比法，对作者设计的2MW风力机叶片进行了复合材料初始铺层设计。建立了完整的复合材料复杂曲面风力机叶片参数化有限元模型。基于修正的动量叶素理论，提出了一种新的风力机叶片流固耦合方法，解决了在叶片结构优化研究过程中气动载荷加载这一关键问题。建立了叶片有限元优化数学模型，将粒子群算法与有限元方法结合起来对复合材料风力机叶片进行优化设计。提出了两种优化设计方案，优化结果表明，在满足失效准则及位移约束的条件下，两种方案对叶片质量的降低均较显著，而方案二(增加叶片主梁位置作为可变量)对叶片质量的减少更为明显，表明该优化设计方法的可行性及优越性；最后对优化方案二所设计出来的叶片进行了应变分析，研究表明优化后的叶片满足强度要求，并指出了叶片最大弯曲应变的位置。本研究对于风力机叶片结构设计及优化具有重要的指导作用，使风力机翼型、叶片气动外形及结构参数化一体化设计成为可能。6）基于气动弹性理论原理，建立了适用于风力机叶片弹性翼型的气动弹性反馈系统模型。针对叶片二元翼段，根据由翼型形状确定的升力系数和气动中心、气流动压与翼型附加扭角的相互影响关系，导出了风力机翼型扭转发散的临界条件，翼型升力与弹性扭角的耦合关系，获得了气动弹性载荷重分布的迭代模型。重点研究了不同翼型（包括笔者设计的CQU-A180翼型）对风力机叶片二元翼段的静气动弹性的影响，在其他条件不变的情况下对比分析了3种不同的翼型对叶片的附加扭角、气动弹性升力分布的影响特性。研究表明，当扭转刚度较小时，翼型的形状对风力机叶片二元翼段的气动弹性反馈系统有一定的影响，同时也验证了笔者设计的CQU-A180翼型气动弹性特性的合理性。此研究对于大型风力机叶片的静气动弹性问题具有理论指导意义。更多还原

【Abstract】 Nowadays, more and more countries have paid attention to the wind energybecause of its advantage of as a clean source of renewable energy. With the emphasison wind power, the wind turbine has been in recent years applied and developed wildly.The wind turbine blades are one of the most important components which take about20%of the whole wind turbine value. Moreover, the determinants for normal andstable operation are good design, reliable quality and superior performance.This work is supported by a grant from the National High Technology Researchand Development program of China (863Program, No.2012AA051301) and NationalNatural Science Foundation of China (No.51175526). Therefore, in this paper, theresearch topic is presented named the study on the parametrized coupled design theoryof wind turbine blade aerodynamic shape and structure. On the basis of the analysis ofdomestic and international wind turbine airfoils, blades shape, blade structure andaeroelastic theoretical methods, the functional integral theory of wind turbine airfoils isstudied. Based on curvature smooth continuity theory, a new method for improvingairfoils is presented. For the medium thickness airfoils, a novel method of airfoilparameterization which combined the airfoil integrated theory and B-spline theory ispresented. Then, using improved particle swarm algorithm and considering fully therequirements of the aerodynamic performance of the wind turbine airfoils and blades,we have designed seven standard airfoils with high aerodynamic performance (therelative thickness of the airfoils is from15%to40%). Then, based on the amendatorywind turbine aerodynamic theory, the shape of wind turbine blade along the span-wisedistribution is designed used CQU-A airfoil series within the region of wholegenerated power for the wind turbine. The multi-objective optimization model with themaximum the power coefficient and smallest blade area is proposed for the pitchregulation wind turbine. The wind turbine blade is designed by using an improvedmulti-objective particle swarm optimization. The results show that the blades exhibithigh performance and light mass. Lastly, the airfoils data, the new blade shapeparameters and the composite blade structure argument are integrated into the variableparametric analytical expression. The parameterized finite element model of thecomposite wind turbine blade is established. The structure of the wind turbine bladeunder the aerodynamic loads is optimized using PSO algorithm. The optimized results indicate that the mass of the blade is reduced. As a result, the new design method forairfoil, blade shape and blade structure is formed. More importantly, it will make thecoupled wind turbine blade shape and elastic deformation possible. The main studyand achievements are as follows:1) The effects of the airfoil geometric and aerodynamic parameter to the airfoilaerodynamic performance are discussed. The calculated method for the airfoilaerodynamic performance is studied. For three different thickness of wind turbineairfoils (WT180airfoil, DU93-W-210airfoil and DU91-W2-250airfoil), the resultsfrom RFOIL software and the results from experiments are analyzed comparativelyanalysis. The study indicates that the RFOIL software can predict the aerodynamicperformance of the wind turbine airfoils. This means that it is suitable for the directdesign method of the airfoils, as well as providing the effective computing tools for theaerodynamic performance of the new airfoil family design.2) In order to optimize wind turbine airfoil series with better aerodynamicperformance, an improved particle swarm algorithm is presented. Firstly, somecommon optimal algorithm used for airfoils are introduced. Then, the standard PSO isintroduced. The advantage and disadvantage between the PSO and other algorithms arecompared in detail. So as to overcome the lack of easily getting local best solution atthe time of the initial optimization, an improved PSO that the inertia weight is the formof inverse hyperbolic cosine function with nonlinear is presented. At the same time,some typical examples are analyzed using this improved PSO. The optimal resultsindicated that the improved PSO is better than the standard PSO whether the bestsolution or the stability. It is validated that the improved PSO has the effectiveness andfeasibility. The study of the improved PSO can provide the foundation of algorithmwhen optimizing the wind turbine airfoils.3) Based on curvature smooth continuity theory, a new method of improvingairfoils is presented. Comparatively, the aerodynamic performances of the new airfoilsuch as maximum lift coefficient, maximum lift-drag ratio, roughness insensitivity andso forth are better than the DU93-W-210airfoil performances. For the wind turbineairfoils with different relative thickness, the optimal design of wind turbine airfoils isstudied by using distinct methods to get airfoil profiles. For the thin thickness airfoils,based on the theory of functional integral design, a method that makes the appropriatenumbers of control variables in order to better controlling airfoil profiles is presented.Considering synthetically the airfoil leading edge roughness sensitivity, off-design condition, stall condition and noise, the thin thickness airfoils are optimized by usingthe improved PSO method coupled the RFOIL software that the aerodynamicperformance can be calculated.3kinds of different thin thickness airfoils namedCQU-A150, CQU-A180, and CQU-A210respectively are designed. For the mediumand thick thickness airfoils, a novel method combined the airfoil integral theory andB-spline is presented. Considering mainly the structural compatibility and theaerodynamic performance, four airfoils with medium or thick relative thickness aredesigned by using the improved PSO method. The names of the four airfoils areCQU-A250, CQU-A300, CQU-A350, CQU-A350and CQU-A400respectively. Theaerodynamic performances of the seven airfoils are analyzed in detail. The new airfoilsshow high aerodynamic characteristics. Compared with the commonly used windturbine airfoils, the new airfoils show the higher lift coefficient and larger lift/dragratio in both smooth condition and rough condition at the main angle of attacks. Theperformances of the new airfoils show a significant improvement compared with thetypical airfoils. In a word, the functional integral design theory is consummated in thisstudy of this chapter, and not only broadening the idea of the wind turbine airfoildesign, but also making a good foundation for designing wind turbine blades.4) Based on the wind turbine aerodynamic theory, the effects of the keyparameters (such as tip speed ratio, wind diameter, Reynolds, blade root loads and soon) to the performance of the wind turbine are analyzed in detail. Then, the shape ofthe wind turbine blade along the span-wise distribution is designed used the newlyCQU-A airfoil series within the region of whole generated power for the wind turbine.The multi-objective optimization model with maximum the power coefficient andsmallest blade area is proposed for the pitch regulation wind turbine. Then themathematical model of design and optimization for a new2MW wind turbine blade isestablished. Lastly, the wind turbine blade is designed by using an improvedmulti-objective particle swarm optimization. The optimization results show that,compared the original2MW wind turbine blade and Tjaere2MW test blade, theperformance of the new designed blade have been improved, and the area issignificantly smaller which means that the mass is reduced greatly and also reduced thematerial cost of the blade. Moreover, the load for the blade root is effectivelycontrolled. The study of the new designed blade provides a theoretical basis for thedesigning high performance, light quality and low-cost wind turbine blade.5) Based on elasticity of the composite wind blade and the equivalent design method which is often used in composite structural design, the initial layout design forthe structure of the composite wind turbine blade is determined. The finite elementparametric model for the blade is established. Based on the modified Blade ElementMomentum theory, a new one-way fluid-structure interaction method is introduced. Aprocedure combining finite element analysis and particle swarm algorithm to optimizecomposite structures of the wind turbine blade is developed. The procedure proposednot only allows thickness variation but also permits the spar cap location variation overthe structure. The results show that, compared to the initial blade, the mass of theoptimized blades is reduced and especially for the scheme Ⅱ (the location of bladespar cap is seen as one of the variables) which exhibit more mass saving. Finally, thestrain of the optimal blade is analyzed, and the location of the max strain of the optimalblade is pointed out. This present study has important significance for the structuraldesign and optimization of wind turbine blades. Moreover, the highly coupledaero-elastic problem of the structure and aerodynamic models can be solved.6) The static aeroelastic basic functions suitable for the two dimensional (2D)airfoil sections of wind turbine blades were derived based on the aeroelasticity theorywithin the linear elastic range. Through taking the attack angle as input, pressure asoutput and the elastic twist angle of the airfoils as the feedback of the system, anaeroelastic feedback model for the elastic airfoils of wind turbine blades wereestablished. Finally, the influence of different airfoils (including the new airfoildesigned by author) on the additional twist angle of the2D airfoil sections and the liftforce distribution of wind turbine blades was mainly studied. The study showed thatthe aerodynamic performance of the airfoils improved with the increased additionaltwist angle when the torsion stiffness is small, and the aerodynamic performance of theairfoils had litter changed with litter increased additional twist angle when the torsionstiffness is large. Meanwhile, the study also indicated that the static aeroelasticcharacteristics of the new airfoil designed by author are reasonable. The considerationof the elastic deformation of blades has important theoretical guiding significance forstudying the aeroelastic problems of large wind turbine blades.更多还原