叶根前缘倒角对低压涡轮转子叶片强度的影响

针对某型航空发动机低压涡轮转子叶片在叶根前缘倒角处发生应力集中的问题,研究了叶根前缘倒角半径对低压涡轮转子叶片强度的影响。研究结果表明,随着叶根前缘倒角半径的增加,低压涡轮转子叶片根部前缘倒角处应力集中效应降低,可作为减少低压涡轮转子叶片疲劳破坏和断裂失效的措施。叶片表面气动力载荷、离心力载荷是导致低压涡轮转子叶片根部前缘倒角处应力集中的主要原因。其中,气动力载荷引起的应力占总等效应力的78%,离心力载荷引起的应力占总等效应力的22%,温度场载荷引起的应力可忽略。     

航空发动机高压涡轮转子叶片叶冠改型分析

以某型号航空发动机高压涡轮转子叶片为研究对象,对其叶冠进行改型分析.应用有限元软件建立模型,对比叶冠改型前后高压涡轮转子叶片的强度及振动特性.分析结果表明,叶冠改型前后高压涡轮转子叶片变形相差很小,叶冠改型后叶片静强度安全因数及抗振能力有较大提高,各阶固有频率均略有降低.由此可见,航空发动机高压涡轮转子叶片叶冠改型效果较好.     

高压压气机转子叶片振动特性分析

基于ANSYS软件对某型航空发动机高压压气机第一级转子叶片的振动特性进行了分析研究,建立了叶片的三维有限元模型,采用分块Lanczos法,计算得到了叶片在发动机常用工况转速下的各阶自振频率、相应振型及振动应力分布,找出了应力较大的薄弱区域.最后考虑了高压压气机进口导流叶片后形成的气流尾迹对此级转子叶片的激振影响,得到该级转子叶片的共振图,结果证明该转子叶片在常用工况转速下,不会因为进口导流叶片后的气流尾迹引发共振.为叶片的后续结构分析、实验及振动排故提供了必要的数值依据.     

叶尖小翼结构对涡轮叶片强度的影响研究

对某型高压涡轮第一级的转子叶尖进行叶尖小翼结构造型,并在级环境下对原始叶片和造型叶片进行定常数值模拟和有限元分析,分析对比了叶尖小翼结构对叶片强度的影响.结果 表明:通过对涡轮叶尖进行叶尖小翼处理,涡轮叶尖小翼对叶身的应力分布规律无明显影响,但是会使叶尖处的高应力区沿叶尖小翼结构延伸至叶顶平面,叶片应力会有一定程度增加...     

透平叶片结构设计与振动特性网格无关性研究

振动损坏是透平转子叶片最主要失效模式之一,其失效关系到整台机组的工作可靠性。为保证全寿命周期内工作安全可靠,在设计阶段需要对透平转子叶片进行详细振动分析,采用有限元法对叶片进行频率分析时,由于叶片网格划分密度的差别,可能对振动特性计算结果造成较大影响。本文根据某型燃机气动设计情况,进行了透平转子叶片结构设计,完成结构设计后,进一步基于ANSYS进行了振动特性分析,通过研究网格密度对叶片振动频率的影响,探究了对该榫接式叶片频率计算结果无影响的合理网格密度,指导后续同类机组透平叶片设计。     

600MW超临界汽轮发电机组低压转子叶片脱落振动特性研究

针对国产600 MW超临界汽轮发电机组低压2转子末级叶片脱落故障问题,开展低压转子叶片脱落对机组轴系振动特性的影响研究。采用有限元法构建轴系动力学模型,进行临界转速与振型分析;通过施加瞬态激励力模拟叶片脱落,建立低压转子叶片脱落瞬态激励模型,开展机组轴系非线性瞬态时域分析,得到工作转速3 000 r/min下轴系叶片脱落和各轴承处振动响应;对比激励前后振动响应,总结低压转子叶片脱落故障对轴系振动的影响规律。研究发现,轴系振型以各跨转子弯曲振型为主,叶片脱落主要影响其所在跨转子的振动特性,且表现为典型的瞬态不平衡振动特性。     

高压二级及低压－级涡轮叶片断裂分析

对涡轮叶片的断裂原因进行了分析。高压二级涡轮叶片裂纹为一弯共振所致；而低压一级涡轮叶片裂纹属高周振动疲劳，裂纹形核较早，但扩展较慢，其折断是在已存在裂纹的情况下，由高压二级涡轮的断片撞击所致。     

高压二级及低压一级涡轮叶片断裂分析

对涡轮叶片的断裂原因进行了分析。高压二级涡轮叶片裂纹为一弯共振所致；而低压一级涡轮叶片裂纹属高周振动疲劳，裂纹形核较早，但扩展较慢，其折断是在已存在裂纹的情况下，由高压二级涡轮的断片撞击所致。     

航空发动机风扇叶片振动应力试验分析

通过试验获取航空发动机转子叶片在实际工作条件下的振动应力,是开展转子叶片设计验证及优化改进的重要手段。以某航空发动机为研究对象,设计风扇叶片振动应力地面试验方案,开展台架试验和装机地面试验,测取风扇叶片振动数据并进行振动应力分析。分析结果表明:装机地面试验中,风扇叶片振动应力较台架试验显著增长,说明发动机安装状态的变化对风扇叶片振动应力有较大影响。     

某航空发动机单晶涡轮叶片研制及应用

某航空发动机所用的K465合金高压涡轮叶片在使用条件下的强度安全裕度较低,在使用考核中造成了高压涡轮叶片烧蚀断裂故障。为保证发动机的性能、寿命及材料整体匹配性的要求,开展了某单晶高温合金及涡轮叶片的研制及应用研究。研制的单晶高温合金不但具有卓越的高温性能,而且还具有优异的工艺性能和抑制再结晶能力。批量试制出了合格的某发动机单晶涡轮叶片,形成了一系列该单晶涡轮叶片工程化制备生产用工艺规范和单晶叶片铸件验收暂行技术条件;单晶涡轮叶片试验件已通过了热冲击试验、振动疲劳试验、转子超温超转试验和发动机整机长期试车试验考核,经受住了严苛的考验。该单晶叶片的研制成功,填补了国内同类产品的空白,该研究成果也可用于其他高推比发动机。     

LP compressor blade vibration characteristics at starting conditions of a 100 MW heavy-duty gas turbine

In this paper are presented the blade vibration characteristics at the starting conditions of the low pressure multistage axial compressor of heavy-duty 100 MW gas turbine. Vibration data have been collected through strain gauges during aerodynamic tests of the model compressor. The influences of operating modes at the starting conditions are investigated upon the compressor blade vibrations. The exciting mechanisms and features of blade vibrations are investigated at the surge, rotating stall, and buffeting flutter. The influences of operating modes upon blade dynamic stresses are investigated for the first and second stages. It is shown that a high dynamic stress peak of 120 MPa can occur in the first stage blades due to resonances with stall cell excitations or with inlet strut wake excitations at the stalled conditions.     

转子对高压涡轮叶尖间隙变化规律的影响

基于涡轮叶尖间隙主动控制的需要,初步分析了涡轮叶尖间隙的变化机理,建立了机匣、叶片和转子的简化模型。在此基础上,分别仿真计算转速变化和发动机起动过程瞬态温度下转子的径向变化,讨论了转子在飞行器机动飞行情况下的振动幅值对叶尖间隙的影响。结果表明,转子振动幅值和径向位移对叶尖间隙变化有重要作用。     

液体涡轮流量传感器叶轮几何参数定量优化方法

以降低传感器特性受被测液体粘度变化的影响为目的，提出了液体涡轮流量传感器叶轮的多参数定量优化方法。该优化方法以叶片顶端间隙与管道半径之比、轮毂半径与叶片顶端半径之比、叶片均方根平均半径位置的叶片安装角、叶片顶端的叶栅实度为传感器叶轮的几何特征参数；传感器用同一仪表系数测量高粘度和低粘度2种液体，以线性度误差最大值为目标函数；以约束条件下n维极值的复形调优法为优化算法。     

A study on an axial-type 2-D turbine blade shape for reducing the blade profile loss

Losses on the turbine consist of the mechanical loss, tip clearance loss, secondary flow loss and blade profile loss etc.,. More than 60 % of total losses on the turbine is generated by the two latter loss mechanisms. These losses are directly related with the reduction of turbine efficiency. In order to provide a new design methodology for reducing losses and increasing turbine efficiency, a two-dimensional axial-type turbine blade shape is modified by the optimization process with two-dimensional compressible flow analysis codes, which are validated by the experimental results on the VKI turbine blade. A turbine blade profile is selected at the mean radius of turbine rotor using on a heavy duty gas turbine, and optimized at the operating condition. Shape parameters, which are employed to change the blade shape, are applied as design variables in the optimization process. Aerodynamic, mechanical and geometric constraints are imposed to ensure that the optimized profile meets all engineering restrict conditions. The objective function is the pitchwise area averaged total pressure at the 30 % axial chord downstream from the trailing edge. 13 design variables are chosen for blade shape modification. A 10.8 % reduction of total pressure loss on the turbine rotor is achieved by this process, which is same as a more than 1 % total-to-total efficiency increase. The computed results are compared with those using 11 design variables, and show that optimized results depend heavily on the accuracy of blade design.     

Analysis of viscosity effect on turbine flowmeter performance based on experiments and CFD simulations

Viscosity effect is one important factor that affects the performance of turbine flowmeter. The fluid dynamics mechanism of the viscosity effect on turbine flowmeter performance is still not fully understood. In this study, the curves of meter factor and linearity error of the turbine flowmeter changing with fluid viscosity variations were obtained from multi-viscosity experiments (the viscosity range covered is 1.0×10^–6 m²/s–112×10^–6 m²/s). The results indicate that the average meter factor of turbine flowmeter decreases with viscosity increases, while the linearity error increases. Furthermore, Computational Fluid Dynamics (CFD) simulation was carried out to analyze three-dimensional internal flow fields of turbine flowmeter. It was demonstrated that viscosity changes lead to changes of the wake flow behind the upstream flow conditioner blade and the flow velocity profile before fluid entering turbine rotor blade, which affect the distribution of pressure on the rotor blades, so impact the turbine flowmeter performance.     

进口探针支杆诱发压气机转子叶片振动的流固耦合研究

针对某压气机试验中发现进口探针支杆的引入导致下游转子叶片发生振动失效的问题开展数值计算研究,采用MPCCI把Numeca和ABAQUS联合起来构建成流固耦合计算平台,数值分析了试验故障工况条件下有/无探针支杆对压气机转子叶片振动特性的影响。结果表明:无探针支杆时转子叶片振动收敛,有探针支杆时不同转子叶片的振动特征不同,至少存在一个转子叶片的振动位移及应变发散,对应于叶片振动失效。     

高速喷漆涡轮转子轴疲劳寿命分析

通过对高速喷漆涡轮转子轴质量等效,将涡轮系统复杂振动转化为简单的单自由度振动问题。在此基础上,论述了等幅应力下有限疲劳寿命分析方法,推算出高速喷漆涡轮转子轴有限疲劳寿命,分析了该转子轴直径、悬臂长、振动幅值及偏心距对疲劳寿命的影响规律。为转子轴的维修和制造奠定基础。     

叶轮扭振引发离散气动噪声理论计算模型研究

对叶轮振动模态进行分析 ,表明由于叶片刚度远小于轮毂的刚度 ,叶轮振动以叶片振动为主 ,而叶片振动低频表现为扭摆振动 ,高频表现为表面弯曲波振动。低频振动对叶轮气动噪声影响很大 ,本文基于Lowson离散噪声模型对叶片扭振引发离散气动噪声声压的估算公式进行了推导 ,为工程应用提供了方便     

Fast-response total pressure probe for turbomachinery application

To evaluate the accurate performance and characteristics of turbomachinery, it is important to measure the unsteady flow phenomena downstream of the rotating blades. This paper presents the development of a fast-response total pressure probe for the measurement of the total pressure field at the exit of blades. The result of measurement in a one-stage axial turbine is also presented. The fast-response total pressure probe is fabricated by installing a fast-response pressure sensor in the cylindrical head of the probe. In terms of simplicity of the measurement system and data reduction method, this method is more competitive over established methods that use more than four sensors. The probe is applied to the one-stage axial turbine in order to measure the instantaneous total pressure downstream of rotor blades. The measured instantaneous signal is decomposed to obtain the blade-to-blade pressure distribution. The pressure distribution due to blade passing is clearly captured. Due to the loss generation in the casing region, the total pressure and its amplitude of fluctuation by the blade passing are lower in the shroud and hub region than in mid-span. The total pressure distribution at the exit of the rotor blade is found to be slightly different from blade to blade due to the geometric difference and the different relative positions of the rotor blades and stator vanes. The developed probe successfully measures the accurate total pressure distribution at the rotor exit, and allows the evaluation of the loss distribution and the accurate performance of turbomachinery.     

核电汽轮机转子在低周疲劳与高周疲劳交互作用下裂纹扩展寿命的研究

提出核电汽轮机转子在低周疲劳与高周疲劳交互作用下裂纹扩展寿命的计算与评定方法。介绍核电汽轮机转子的低周疲劳与高周疲劳的应力幅与应力范围、低周疲劳裂纹扩展寿命与高周疲劳扩展寿命的计算方法。给出了核电汽轮机转子在低周疲劳与高周疲劳交互作用下裂纹扩展日历寿命的计算与评定方法,以及1 000 MW级核电汽轮机焊接低压转子疲劳裂纹扩展日历寿命的计算与改进的应用实例。结果表明,高周疲劳对汽轮机转子疲劳裂纹扩展日历寿命有比较大的影响,新研制核电汽轮机的转子结构设计和在役核电汽轮机的转子安全性评定,需要评估转子在低周疲劳与高周疲劳交互作用下裂纹扩展 寿命。