民用航空发动机风扇叶片适航符合性设计与验证方法研究

发布时间：2018-09-07 16:19

【摘要】：民用涡扇航空发动机为了提高涵道比和效率,必须采用大尺寸的风扇叶片,大尺寸风扇叶片已经成为民用航空发动机的一个典型特征。以风扇叶片为典型部件的先进部件设计技术已经成为新一代航空动力的主要技术。随着国产大涵道比涡扇发动机的研制,民用航空发动机适航性设计和验证问题已经成为学术界和工业界关注的问题,风扇叶片作为大涵道比发动机最前端和最典型部件之一,其适航性设计和验证也具有典型的代表性。本文从民用航空发动机风扇叶片适航性设计和验证出发,系统研究了风扇叶片适航性设计涉及的理论和验证方法,从风扇叶片参数化建模和结构优化、振动适航性设计和验证、鸟撞适航性设计和验证、冰撞击及等效安全验证,符合性仿真验证平台等方面开展系统的设计和验证工作。通过广泛的数值分析和部件验证,减少风扇台架试验的风险,提高适航认证的成功率。论文主要研究成果如下:(1)针对航空发动机宽弦弯掠大风扇叶片造型复杂问题开展了风扇叶片参数化和稳健性优化研究。基于特征造型技术,通过叶身、圆弧榫头、伸根段三个特征的参数化构建了风扇叶片几何参数化建模方法。提出以三阶非均匀有理B样条实现风扇叶片型线的设计与积叠成型方法,解决了以两端中点和重心点为核心的风扇叶片圆弧榫建模以及自由曲面向矩形截面的光滑过渡造型难点。实现了风扇叶片的三维几何建模,并基于UG OPEN/API二次开发技术实现了造型的自动生成。在风扇叶片结构参数的基础上,进一步提出风扇叶片结构稳健性优化设计方法,根据风扇叶片四个截面的偏移量和DOE方法构造叶片重量、静强度、振动、鸟撞的近似响应面模型,实现了风扇叶片的稳健性优化设计。为风扇叶片的快速建模提供方法和手段,提高了风扇叶片结构的稳健性,并为风扇叶片的适航性设计和验证提供了基础;(2)针对航空发动机风扇叶片振动符合性设计和验证全过程涉及的流程、方法、准则、试验验证等技术难题,从振动条款的要求出发,提出了风扇叶片振动符合性的技术要求、符合性过程、模态识别和应力识别方法、元件级和部件级验证、整机级验证方法,构建了风扇叶片振动符合性分析和试验验证的全寿命周期方法。形成了以耐久极限百分比λ、应变片相对应变λ、各模态相对应变λ为核心的动应力识别和数据处理准则。基于参数化的风扇叶片模型,采用仿真分析方法对风扇叶片的振动特性和振动应力进行计算,并通过元件级和部件级试验验证风扇叶片相对振动应力分布以及抗高周疲劳能力。分析和试验结果表明,该风扇叶片的振动特性和振动应力水平满足本文提出的适航条款设计要求,风扇叶片相对应力分析结果与试验结果比较吻合,部件具备了抗高周疲劳能力,为风扇叶片振动符合性设计与验证提供了方法和依据;(3)针对航空发动机鸟撞条款设计和验证涉及的不同类型鸟撞数值仿真分析、元件级鸟撞试验、部件级鸟撞试验符合性验证等技术难题,分析风扇叶片大鸟、中鸟及大型群鸟鸟撞的适航性要求和判断准则。构建了经过元件级试验验证的鸟体本构模型和风扇叶片高应变率本构模型,并采用高速冲击试验进一步验证了风扇叶片鸟撞分析模型。在经过验证的鸟撞分析模型上通过仿真方法分析了风扇叶片抗大鸟、中鸟和大型群鸟撞击的能力,形成了大鸟鸟撞和中鸟鸟撞危险点分析方法,提出了基于大型群鸟和中鸟鸟撞后风扇叶片变形的功率下降分析方法,实现了以仿真分析为主的风扇叶片鸟撞符合性设计和验证手段。分析表明,所设计的风扇叶片在大鸟撞击下最大叶片损失为27%,在大型群鸟和中鸟撞击过程中功率下降18.5%,具备抵抗大鸟、大型群鸟、中鸟撞击的能力。为风扇叶片抗鸟撞设计与验证提供了可行的方法和模型;(4)针对航空发动机风扇叶片涉及的结冰和冰撞击问题,提出了发动机进气系统结冰气象参数条件、发动机参数条件、结冰要求以及风扇叶片冰撞击要求。分析了包含连续最大、间断最大、混合最大结冰状态以及起飞、起飞爬升、航路爬升、下降、空中等待、进场和着陆等全过程结冰情况,提出了风扇叶片旋转结冰和冰生长分析方法。基于风扇叶片结冰分析、冰撞击关键点分析以及冰撞击模型验证,从结冰条件、旋转结冰分析、冰撞击关键点分析以及冰撞击分析方法方面建立了风扇叶片在结冰和冰撞击方面的验证方法,进一步提出了等效安全在发动机风扇叶片适航验证方面的应用,为风扇叶片的适航符合性设计和验证提供了依据;(5)针对风扇叶片适航符合性快速仿真验证与优化问题,在风扇叶片适航性设计和验证的基础上,提出了基于部件、整机以及数据关联的适航仿真验证平台理论框架,并根据软件开发规范开发了一套风扇叶片适航符合性仿真验证平台,实现了风扇叶片的参数化设计集成、风扇叶片的振动符合性验证、鸟撞符合性验证、结构优化设计。
[Abstract]:In order to improve the bypass ratio and efficiency of civil turbofan aeroengine, large-sized fan blades must be used. Large-sized fan blades have become a typical feature of civil aeroengine. The airworthiness design and validation of a specific turbofan engine has become a major concern in academia and industry. As one of the most advanced and typical components of a high bypass ratio engine, the fan blade is also a typical representative of the airworthiness design and validation. Based on the airworthiness design and verification, the theory and verification methods involved in the airworthiness design of fan blades are systematically studied. The system design is carried out from the aspects of parametric modeling and structural optimization of fan blades, vibration airworthiness design and verification, bird impact airworthiness design and verification, ice impact and equivalent safety verification, and conformance simulation verification platform. Through extensive numerical analysis and component verification, the risk of fan bench test is reduced and the success rate of airworthiness certification is improved. The main research results are as follows: (1) The parameterization and robustness optimization of fan blades are carried out to solve the complex modeling problem of large fan blades with wide chord bending and sweeping. The geometric parameterization modeling method of fan blade is constructed by parameterization of blade body, arc tenon and root stretching section. The design and stack forming method of fan blade profile based on third-order non-uniform rational B-spline is proposed, which solves the problem of fan blade arc tenon modeling and freedom with center of gravity and center of both ends as the core. It is difficult to smooth the transition from curved surface to rectangular section. The 3D geometric modeling of fan blade is realized, and the modeling is automatically generated based on UG OPEN/API secondary development technology. The approximate response surface model of blade weight, static strength, vibration and bird impact is constructed by displacement and DOE method, which realizes the optimal design of fan blade robustness. The technical problems involved in the whole process of fan blade vibration conformance design and verification, such as flow, method, criterion and test verification, are discussed. Based on the requirements of vibration clauses, the technical requirements, conformity process, modal identification and stress identification methods, component and component level verification, and the whole machine level verification method are proposed. The dynamic stress identification and data processing criteria based on the durability limit percentage lambda, the relative strain lambda and the relative strain lambda of each mode are established. Based on the parameterized fan blade model, the simulation analysis method is applied to the fan blade. Vibration characteristics and vibration stress are calculated, and the relative vibration stress distribution and high cycle fatigue resistance of fan blades are verified by component-level and component-level tests. The analysis results are in good agreement with the test results, and the components have the ability to resist high cycle fatigue, which provides a method and basis for the design and verification of fan blade vibration compliance. (3) The different types of bird impact numerical simulation analysis, element-level bird impact test and component-level bird impact test are involved in the design and verification of aircraft engine bird impact clauses. The airworthiness requirements and judgment criteria of bird impact on fan blades are analyzed. The bird constitutive model and high strain rate constitutive model of fan blades are constructed. The bird impact analysis model is further validated by high-speed impact test. In the analysis model, the ability of the fan blade to resist the impact of large birds, medium birds and large flocks of birds is analyzed by simulation method, and the dangerous point analysis method of the large bird impact and medium bird impact is formed. The power drop analysis method based on the deformation of the fan blade after the impact of large and medium birds is proposed, which realizes the fan blade bird with simulation analysis as the main method. The results show that the maximum blade loss of the fan blade is 27% under the impact of large birds and 18.5% during the impact of large and medium birds. The fan blade has the ability to resist the impact of large, large and medium birds. 4) Aiming at the icing and ice impact problems in the fan blade of aeroengine, the ice meteorological parameters, engine parameters, ice requirements and fan blade ice impact requirements of the engine intake system are proposed. Based on the analysis of fan blade icing, the analysis of key points of ice impact and the validation of ice impact model, the methods of freezing conditions, rotating ice analysis, key point analysis of ice impact and ice impact analysis are established. The validation method of fan blade in icing and ice impact is put forward, and the application of equivalent safety in airworthiness validation of engine fan blade is put forward, which provides the basis for the design and validation of fan blade airworthiness. (5) Aiming at the problem of fast simulation validation and optimization of fan blade airworthiness, the airworthiness of fan blade is set up. On the basis of calculation and verification, a theoretical framework of airworthiness simulation and verification platform based on component, whole machine and data association is proposed, and a set of simulation and verification platform for fan blade airworthiness is developed according to software development specification. The integration of fan blade parametric design, the verification of fan blade vibration compliance and bird impact compliance are realized. Verification, structural optimization design.
【学位授予单位】：南京航空航天大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：V232

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