三维涡轮叶片交互式造型程序设计

介绍和讨论了十二参数法、预置曲率法、和Bezier曲线法三种典型的涡轮叶片解析造型方法的原理和步骤,以及叶片的三维复杂成型方法。并且编制了基于以上方法的三维涡轮叶片造型交互式程序,以设计实例阐述了叶片造型原理和步骤、交互式程序的编制方法和功能。分析和讨论说明：该程序便捷、高效、可靠,具有强的干涉性和交互性,能够满足复杂的涡轮三维弯扭掠叶片造型工程实用需要。     

风电叶片用环氧树脂和不饱和聚酯性能的对比研究

对比了环氧树脂和不饱和聚酯的各项性能,通过对树脂的黏度-时间曲线测试,结果显示不饱聚酯在整个操作时间内黏度变化不大,具有优异的工艺调控性。结合扫描电子显微镜(SEM)对两种树脂断口形貌的观察和力学性能测试来研究两种树脂的区别,结果表明,虽然不饱和聚酯的弯曲强度和抗压强度较高,但是平均2.41%的断裂伸长率远低于环氧树脂的8.71%。由玻璃化转变温度(Tg)测试分析主要是不饱和聚酯内自由体积较低,在本体受到拉伸时无法通过分子内链段的运动来降低体系内拉应力,所以本体脆性增大,最终导致了材料在变形量较大时的使用受到限制。     

Domestic object damage investigations on turbine blade material

Domestic Object Damage (DOD) is a problem, especially for compressor and turbine sections of jet engines. To investigate the influence on the performance and service life of the impacted components, well defined DOD impacts in the laboratory have been performed with consecutive metallurgical investigations and fatigue testing. The paper describes the efforts to upgrade the existing flat coil accelerator at the Fachgebiet Raumfahrttechnik (lrt) to the needs of the DOD tests and documents the experiment set up. Particles were shot on ideal flat specimens of Titanium Aluminides (γ-TiAl based alloys) under realistic service conditions simulating stress and/or temperature of the target. First experimental results are discussed.     

三维涡轮叶片气动优化方法的研究

提出一种进行三维涡轮叶片气动优化的多目标多约束方法.根据五次多项式方法进行三维涡轮叶片的参数化建模,采用N-S(Navier-Stokes)方程和湍流模型进行三维流场分析计算,K-S(Kreisselmeier-Steinhauser)函数法作为优化方法,利用近似技术加速循环优化速度,以气动效率和总压比为目标函数,对涡轮叶片进行多目标气动优化、形状优化.算例表明,使用该方法能使涡轮叶片的性能得到明显改善,证明提出的优化方法可行有效.     

风力机叶片的形状优化设计

在风力机优化设计过程中,考虑法向力和切向力的叶尖损失,基于一维的动量叶素理论及传统的风力机空气动力学原理,推导并给出新的风力机轴向和周向因子的计算模型。探讨风力机成本和输出能量之间的关系,得到风力机成本及其年输出能量的计算模型,进而建立风力机单位输出能量成本的数学模型,以其为优化设计目标,以叶片的形状参数弦长、扭角和相对厚度为优化设计变量,提出叶片的优化设计数学模型。最后,应用该优化模型对某2MW风力机叶片进行优化设计,并对优化结果进行比较分析,验证了优化叶片的工作性能,很好地实现了风轮单位能量成本的降低。研究成果为大功率风力机叶片的设计开发提供了理论依据,奠定了风力机叶片的研究和工业应用前景。     

轴流式压缩机叶片静态特性分析

以轴流压缩机动叶片为研究对象,利用ANSYS软件研究了在3种不同工作载荷情况下叶片的静态特性,得到其应力与变形的分布规律。研究结果表明:叶片的高应力主要由离心力引起,高应力区主要集中在叶根榫槽处,在叶身部位其应力均较小;气流力则主要引起叶片的大变形,出现在叶顶部位,并向叶根呈阶梯递减,其应力主要集中在叶身与叶根的相交处。针对该研究结果提出相应的改进措施,为此类叶片的结构优化或性能优良叶片的再设计提供了参考。     

Frontiers of research and future directions in information and communication technology

Information and communication technology (ICT), characterized by continual innovation and rapid technological change, is having a tremendous impact on society. Research and development in ICT are being conducted throughout the technology sector, and fundamental research is being carried out in many university departments of electronics, computer science, and engineering. This paper deals with frontiers of research and trends in selected areas of ICT, including computer hardware, microelectronics, and semiconductor devices and materials—areas that are leading the innovations in ICT. It briefly describes emerging technological developments, and concludes with advances in software engineering.     

基于UGNX的航空发动机叶片造型方法研究

对航空发动机的关键元部件之一——涡轮叶片进行了三维空间造型方法的研究。基于UGNX的自由曲面造型功能，采用双三次B样条拟合方式建立了叶片型面的空间样条曲线模型，由此来构造叶片空间型面。同时对叶片曲面造型中的几个关键问题从数学上进行了分析和探讨，验证了其造型方法的可行性，这为后续叶片加工精度分析和误差补偿提供了理论依据。     

A simple mixed-based approach for thin-walled composite blades with two-cell sections

In this work, a mixed beam approach that combines both the stiffness and the flexibility methods has been performed to analyze the coupled composite blades with closed, two-cell cross-sections. The Reissner’s semi-complementary energy functional is used to derive the beam force-displacement relations. Only the membrane part of the shell wall is taken into account to make the analysis simple and also to deliver a clear picture of the mixed method. All the crosssection stiffness coefficients as well as the distribution of shear across the section are evaluated in a closed-form through the beam formulation. The theory is validated against experimental test data, detailed finite element analysis results, and other analytical results for coupled composite blades with a two-cell airfoil section. Despite the simple kinematic model adopted in the theory, an accuracy comparable to that of two-dimensional finite element analysis has been obtained for cases considered in this study.     

聚苯乙烯泡沫作为风电叶片夹芯材料的可行性研究

讨论了聚苯乙烯(PS)泡沫在风电叶片中的应用,通过对比研究聚氯乙烯(PVC)泡沫和PS泡沫本体以及泡沫玻璃钢夹芯结构的力学性能,通过有限元模拟夹芯结构悬臂梁在加载后发生的位移值来判断PS泡沫作为夹芯结构的芯材对整体刚度的影响,并通过实验测量和有限元模拟泡沫夹芯结构。结果显示,PS泡沫本体力学性能较PVC低;PS泡沫作为夹芯结构的芯材可以使用在叶片的剪切腹板中,在替代PVC泡沫使用在壳体蒙皮的夹芯层中,若要保证蒙皮的刚度不变则需要增加PS泡沫的厚度。