【作者】 王博；

【导师】 徐国华；

【作者基本信息】 南京航空航天大学 ， 飞行器设计， 2012， 博士

【摘要】 具有非常规桨叶气动外形的先进旋翼的气动特性数值模拟及优化设计方法研究是直升机空气动力学领域富有挑战性的研究课题。本文一方面开展了适合于优化分析的高精度CFD旋翼气动外形计算方法研究，发展了相应的网格技术和流场求解器，进行了桨叶外形参数对旋翼气动性能的影响分析及优化研究。另一方面，提出了“CLOR”先进旋翼的改进设计—“CLOR-II”，开展了悬停、前飞状态气动特性试验研究以及外场气动噪声试验研究。主要工作包括以下几个方面：作为前提和背景，本文首先阐述了桨叶气动外形对直升机旋翼流场和气动特性的重要影响，并对直升机旋翼流场数值模拟技术及气动特性研究、旋翼气动外形研究、旋翼气动外形优化设计研究等内容的国内外现状进行了概述，指出了现有研究中存在的不足以及难点，提出了本文拟采用的研究方法和内容。根据气动外形优化设计的需要，第二章建立了一种高效、鲁棒的参数化桨叶网格生成方法。同时根据网格特点给出了一个新的快速、自动的运动嵌套网格间单元对应关系判断策略，以用于运动嵌套网格单元判定和贡献单元搜索。以桨叶网格生成技术为基础，结合运动嵌套网格技术，本文又发展了适合于悬停和前飞状态旋翼流场数值计算的方法。为更好地模拟旋翼尾迹的影响，空间离散采用了低耗散的Roe-MUSCL计算格式，为计入桨叶近场的粘性影响，采用了鲁棒性好的B-L湍流模型，并采用了对称边界条件、隐式残值光顺、当地时间步长等方法加速流场计算。作为算例验证，应用该方法计算了具有不同桨叶气动外形的旋翼的流场特性，并与可得到的试验结果进行了对比。应用上一章建立的流场数值方法，开展了旋翼翼型、后掠、下反等外形参数的影响研究。分别计算了不同弯度、最大弯度位置和厚度等翼型参数对旋翼气动特性的影响，分析了后掠、下反桨尖不同起始位置和变化角度对旋翼气动特性影响的特点。然后，将前文建立的CFD方法和代理模型方法相结合展开了旋翼桨叶气动外形的优化研究。分别对旋翼扭转、后掠和下反等参数进行了优化计算与分析，并与参考桨叶进行了对比，验证了优化方法的有效性，得到了一些有意义的结论。最后，本文着重开展了“CLOR-II”旋翼气动和噪声试验的研究。设计并制作了矩形、后掠和“CLOR-II”桨尖的模型旋翼，在风洞中测量了悬停及前飞状态的旋翼气动力，并在外场进行了旋翼的悬停噪声试验，对比分析了三种模型旋翼的气动和噪声特点。作为试验的补充，亦采用数值方法对更高桨尖马赫数状态下试验旋翼进行了数值模拟，并对结果进行了进一步分析。更多还原

【Abstract】 The numerical simulation of aerodynamic characteristics and optimization for advanced rotors withnonconventional aerodynamic-shape blade is a highly challenging subject in the field of HelicopterAerodynamics. On the one hand, the high-accuracy computational fluid dynamics (CFD) method onrotor aerodynamic shape for optimal analysis has been investigated in this thesis, and thecorresponding grid technology and flowfield solver are also developed. Meanwhile, the analysis andoptimization on the effects of blade shape parameters on the rotor aerodynamic performance havebeen done. On the other hand, an improved design of the "CLOR" advanced rotor has beenperformaned and a new modification version, called "CLOR-II", has been put forward. And theexperimental research of aerodynamic characteristics in hover and forward flight as well as theoutdoor noise measurement have been conducted. The major contributions of the author’s researchwork are as follow:As the background of present work, the important effects of the blade aerodynamic shape onhelicopter rotor flowfield and aerodynamic characteristics are firstly described. The research anddevelopment in the field of numerical simulation of helicopter rotor flowfield and aerodynamiccharacteristics, and the field of the rotor aerodynamic shape and its optimal design are brieflyintroduced. The insufficiency and difficulties in the current researches are also pointed out. In addition,the methods used in the present resaerch are briefly brough forward.According to the optimal design requirement of blade aerodynamic shape, a kind of high-efficientand robust parametric blade grid generation method has been established in Chapter2. At the sametime, from the characteristic of the grids, a new and efficient judgmental method for thecorresponding relations between overset grids is given, which has been used to the judgment anddonor seaching of overset grids.Based on the blade grid generation and moving embeded grid technique, a numerical method isdeveloped to solve the flowfield of helicopter rotors in hover and forward flight. In order to simulatethe effects of rotor wake, the spatial discretization uses the low dissipation Roe-MUSCL scheme. Toconsider viscous effect of blade near field, the robust B-L turbulent model is adopted, and thesymmetrical boundary condition，implemented residual smoothing, local time-stepping are used toaccelerate computations. As a numerical example, the rotor flowfield characteristics for differentblade aerodynamic shapes are calculated by the application of this method, and the numerical resultsare compared with available experimental data for validation purpose. By applying the flowfield solver developed, the influence reaserch of the parameters such as rotorairfoil, backward-swept and anhedral angles are carried out. The airfoil parameters, including thecamber, maximum camber location, thickness and so on, are investegated. And the influence of thedifferent blade tips including swept and anhedral angles on the rotor aerodynamic characteristics isanalysed.Then, the optimization research of the rotor blade aerodynamic shape is carried out by combiningthe present CFD method with optimal surrogate model. Respectively, the optimal calculation andanalysis of blade parameters on twist, swept and anhedral angles are made and the optimal results arealso compared with the reference blade. The capability of this optimal method is demonstrated, somemeaningful conclusions are also obtained.Finally, the aerodynamic and noise experimental research on "CLOR-II" rotor are emphaticallyinvestigated. The three model rotors with rectangular, swept and "CLOR-II" blade-tips are designedand manufactured. The rotor aerodynamic forces are measured at hovering and forward-flightconditions in windtunnle and the hovering rotor noise test is done in the outfield. The rotoraerodynamic and noise characteristics among the three model rotors are compared and analyzed. Asthe supplement of experiments, the numerical method is adopted to calculate the aerodynamics athigher blade-tip Mach number and the results are further analyzed.更多还原