大型涡轮转子叶片熔模精铸特点

阐述了用熔模精密铸造制作大型涡轮转子的工艺。介绍了以模料选择、采用冷蜡芯工艺制模、浇注系统设计、合理选择浇注温度和铸型温度等措施，来避免缩松和防止叶片的弯扭变形，并对叶片铸件采用静压矫正。     

双主轴加工单元取代专用机床

加工中心日益取代组合机床和专用机床.其原因是:由于托盘交换和刀具交换而始终存在的影响生产率和有碰撞危险的缺点可以用新结构的机床加以避免.首次在2000年的Metav展会上展示的柔性加工单元就是一个证明.     

用铣床直接加工涡轮叶片

~~用铣床直接加工涡轮叶片@Thomas Schnider @杨春林~~     

双主轴加工单元取代专用机床

加工中心日益取代组合机床和专用机床。其原因是：由于托盘交换和刀具交换而始终存在的影响生产率和有碰撞危险的缺点可以用新结构的机床加以避免。首次在2000年的Metav展会上展示的柔性加工单元就是一个证明。     

用铣床直接加工涡轮叶片

在自由表面的精加工中，优化五轴联动铣削的应用需要新的CAM功能。应用新的铣削方法，也就是P铣削，所取得的初步经验表明，由于优化了精加工工艺，已在透平叶片的生产中得到了所期望的成果。以下是阐述这一新方法的报告。     

涡轮叶片经济性研磨加工方略

在加工制造涡轮叶片时要对弯曲面进行内加工和外加工,还有些涡轮叶片部位接近性差,而且涡轮叶片材料也难于切削,     

涡轮叶片经济性研磨加工方略

在加工制造涡轮叶片时要对弯曲而进行内加工和外加工,还有此涡轮叶片部位接近性差,而且涡轮叶片材料也难于切削。     

涡轮增压器叶片加工方法的比较

通过对两种涡轮增压器叶片加工方法的比较,确定了线切割加工叶片的新方法,并取得了满意的生产效果。     

涡轮叶片电解加工的流场仿真分析

涡轮叶片是航空发动机中的重要零件,主要加工方式是电解加工。基于电解加工流场理论,建立涡轮叶片的三维模型和电解加工的流场模型。应用COMSOL Multiphysics软件对涡轮叶片电解加工进行流场仿真分析,研究流场的分布及特性,分析不同加工间隙和不同电解液压力对流场的影响。通过分析,得出涡轮叶片电解加工时加工间隙、电解液压力与流场流速之间的关系。     

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。     

真空泵转子加工工艺及工装改进设计

针对真空泵转子加工中的精度超差、叶片槽底有振纹等问题,重排了机加工工艺规程,设计了铣叶片槽专用平口钳工装.通过对专用平口钳工装的定位误差分析,验证了其方案可行性.新工艺规程的执行和新工装的应用,保证了产品质量,降低了工人劳动强度.     

基于UG的大型水轮机叶片多轴数控加工研究

以UG自动编程软件体系架构为依据,研究大型混流式水轮机叶片多轴数控加工方法。探讨提高叶片加工质量和效率的途径。介绍大型水轮机叶片五轴联动数控加工雕塑曲面编程中涉及到的转轮叶片三维造型、切削仿真、刀具轨迹生成等关键技术。该方案切削力小、加工精度高、成本低,具有一定的参考价值。     

An experimental study of the performance characteristics with four different rotor blade shapes on a small mixed-type turbine

A small mixed-type turbine with a diameter of 19.9 mm has been substituted for a rotational part of pencil-type air tool. Usually, a vane-type rotor is applied to the rotational part of the air tool. However, the vane-type rotor has some problems, such as friction, abrasion, and necessity of accurate assembly etc.,. These problems make the life time of the vane-type air tool short, but air tools operated by mixed-type turbines are free of friction and abrasion because the turbine rotor dose not contact with the casing. Moreover, it is assembled easily because of no axis offset. These characteristics are merits for using air tools, but loss of power is inevitable on a non-contacting type rotor due to flow loss, tip clearance loss, and profile loss etc.,. In this study, four different rotors are tested, and their characteristics are investigated by measuring the specific output power. Additionally, optimum nozzle location against the rotor is studied. Output powers are obtained through measured pressure, temperature, torque, rotational speed, and flow rate. The experimental results obtained with four different rotors show that the rotor blade shape greatly influences to the performance, and the optimum nozzlc location exists near the mid span of the rotor.     

螺旋罗茨转子四轴加工刀路规划

通过分析螺旋罗茨转子的成型规律,建立了球头刀加工螺旋转子的加工模型,规划了刀具路径,通过等弧长平分法和控制残留高度的等参数法两种方式处理转子端面型线数据点,比较了两种数据点处理优缺点,在此基础上定制了一种规律化的四轴编程模版,采用该模版不需太多编程经验可以快速编制加工程序,从而高效加工螺旋转子,在实际加工中,取得了较好的社会经济效益.     

Development of a water droplet erosion model for large steam turbine blades

Water droplet erosion is one of major concerns in the design of modern large fossil steam turbines because it causes serious operational problems such as performance degradation and reduction of service life. A new erosion model has been developed in the present study for the prediction of water droplet erosion of rotor blades operated in wet steam conditions. The major four erosion parameter ; impact velocity, impacting droplet flow rate, droplet size and hardness of target are involved in the model so that it can also be used for engineering purpose at the design stage of rotor blades. Comparison of the predicted erosion rate with the measured data obtained from the practical steam turbine operated for more than 90.000 hours shows good agreement.     

Effects of combustor-level high inlet turbulence on the endwall flow and heat/mass transfer of a high-turning turbine rotor cascade

Experimental data are presented which describe the effects of a combustor-level high free-stream turbulence on the near-wall flow structure and heat/mass transfer on the endwall of a linear high-turning turbine rotor cascade. The endwall flow structure is visualized by employing the partial- and total-coverage oil-film technique, and heat/mass transfer rate is measured by the naphthalene sublimation method. A turbulence generator is designed to provide a highly-turbulent flow which has free-stream turbulence intensity and integral length scale of 14.7% and 80mm, respectively, at the cascade entrance. The surface flow visualizations show that the high free-stream turbulence has little effect on the attachment line, but alters the separation line noticeably. Under high free-stream turbulence, the incoming near-wall flow upstream of the adjacent separation lines collides more obliquely with the suction surface. A weaker lift-up force arising from this more oblique collision results in the narrower suction-side corner vortex area in the high turbulence case. The high free-stream turbulence enhances the heat/mass transfer in the central area of the turbine passage, but only a slight augmentation is found in the endwall regions adjacent to the leading and trailing edges. Therefore, the high free-stream turbulence makes the endwall heat load more uniform. It is also observed that the heat/mass transfers along the locus of the pressure-side leg of the leading-edge horseshoe vortex and along the suctionside corner are influenced most strongly by the high free-stream turbulence. In this study, the endwall surface is classified into seven different regions based on the local heat/mass transfer distribution, and the effects of the high free-stream turbulence on the local heat/mass transfer in each region are discussed in detail.     

涡轮叶片位移场模型变形特征解耦方法研究

为了有效提高航空发动机精铸涡轮叶片的成形精度,提出一种涡轮叶片位移场模型的变形特征解耦方法。首先通过对批量叶片进行检测,获取型面数据后与叶片设计模型配准及偏差计算得到叶片精铸位移场;在对精铸位移场进行分析和研究的基础上,确定叶片铸件变形的分布规律。研究精铸涡轮叶片的变形特征,通过位移场的解耦分析把精铸位移场中的任意位移矢量分解成收缩误差变形矢量、弯曲变形矢量、扭转变形矢量。分离出的精铸变形特征可应用于精铸涡轮叶片模具型腔优化过程中,对提高模具型腔的设计质量及涡轮叶片的成形精度具有重要意义。     

基于仿真的大型水轮机叶片三轴加工工艺及程序优化

由于经济和技术等方面的原因,目前国内仍广泛采用三轴联动数控机床来加工大型水轮机叶片.在加工工艺规划与编程过程中,如何既保证叶片加工精度要求叉提高加工效率是其关键技术之一.根据大型水轮初叶片曲面的特点,并结合简化加工工艺的要求,对商业软件进行二次开发,得到相应的仿真加工技术.采用计算机仿真加工来评估加工工艺方案和优化刀具轨迹,实现多方案、多加工参数的优选和优化,经过验证表明能够有效保证加工精度和提高效率.     

面向加工中心的高速铣刀优选系统

针对加工中心高速铣削中刀具及其切削参数选择问题,以已有高速铣削机理研究成果为基础,进行工件高速铣削加工特征研究,并建立高速铣刀优选目标模型和优选规则,完成了基于关系型数据库的高速铣刀优选系统的开发.结果表明,采用该系统优选的铣刀及其切削参数进行高速铣削加工,能有效提高加工品质和加工效率、降低加工成本.