无夹具制造中工件寻位的一种新方法

本文对无夹具制造中的工件寻位问题进行了理论分析，找出了问题的难点，提出了可行的解决办法。在此基础上建立了工件寻位的线性化数学模型，研究出了求Ｔ矩阵的快速迭代算法，开发了工件寻位软件并进行了实验验证。理论分析与实验结果表明，本文提出的方法可行，为无夹具制造系统的实现奠定了必要的理论与技术基础。     

分布式网络化制造系统构想

从全球化趋势,市场特征和科学技术发展等方面讨论制造模式变革的必然性,提出一种面向新世纪的分布式网络化制造系统的初步构想,并就其特点及关键技术进行阐述,通过原型系统从原理上实现了这一构想。     

可重构制造单元控制系统设计

网络化制造将是信息时代的主要生产模式 ,制造系统可重构是网络化制造的关键单元技术。在分析了网络化制造环境对可重构制造系统体系结构要求的基础上 ,提出了一种支持制造系统可重构的单元控制器设计方案 ,并详细介绍了该控制器的软件框架结构、功能模块和实现技术。     

可重构制造单元控制系统设计

网络化制造将是信息时代的主要生产模式,制造系统可重构是网络化制造的关键单元技术,在分析了网络化制造环境对可重构制造系统体系结构要求的基础上,提出了一种支持制造系统可重构的单元控制器设计方案,并详细介绍了该控制器的软件框架结构,功能模块和实现技术。     

基于知识集成的车间制造系统运行模式研究

为了有效地提高车间制造系统的制造执行能力,实现车间制造过程的优化运行,提出了一种基于知识集成的车间制造系统运行模式,详细分析了该运行模式的实现思路和构成,以及实现该模式的基于制造资源封装的工作中心服务化技术、基于知识集成的制造执行链构建方法等关键技术.最后,结合一个应用案例,验证了该运行模式的可行性和有效性.     

云制造模式下制造能力建模关键技术

阐述了云制造模式下制造能力的内涵,并对制造能力模型构建及描述机制等关键技术做了深入探讨。归纳和总结了当前制造能力研究现状及存在的主要问题,给出了云制造模式下制造能力的概念与分类。构建了制造能力多维信息模型,并给出了针对该模型的制造能力描述框架,为最终实现制造能力形式化描述提供了支持。结合云制造模式下对制造能力共享的实际需求,依据所提出的建模理论和技术,初步开发了一个支持用户按需使用的制造能力服务化系统原型。     

特许连锁模式下的模具制造网格系统架构

针对我国模具制造业的现状和国际市场的需求，提出了采用特许连锁的模式来改造我国的模具制造企业，并分析了该模式对制造系统的特定要求。借鉴网格计算的理念，提出了与特许连锁相匹配的模具网格化制造系统的新构想，探讨了模具制造网格系统的基本架构。制造网格系统的研究、开发与实施，将为我国模具制造特许连锁模式提供切实可行的实现途径。     

基于异构Agent系统的虚拟制造单元

虚拟制造单元是虚拟制造系统的一个重要组成部分。本文分析了Agent系统特点 ,提出了一种基于异构A gent系统的虚拟制造单元 ,并建立了审慎式Agent和反应式Agent并存的系统体系结构。根据系统分层和异构的特点 ,定义了Agent的结构模型及其运行模式。采用过程调用模式与消息模式相结合的方式解决了各Agent之间的通信问题。根据所提出的观点并利用相关的开发工具 ,初步实现了一个虚拟制造单元     

面向可重构制造系统的敏捷夹具设计

分析了可重构制造系统的特点，把可重构思想引入到夹具设计系统中。介绍了建立柔性和刚性特点的夹具组件数据库结构的方法；提出采用可重构组件模块进行夹具规划的思想，进而提高夹具设计的自动化。     

柔性组合夹具在汽车零部件制造中的应用

柔性组合夹具是基于传统组合夹具并依托柔性制造技术发展而产生的一种夹具系统。我国汽车制造业从20世纪六七十年代开始,就广泛采用组合夹具,它当时被称为"先进工艺设备",并取得了可喜的成果。80年代后,随着现代化制造理念和柔性制造技术在汽车制造业中的广泛应用,传统的组合夹具亦随之发生了变化,并在当今汽车制造业的柔性制造技术环境下,仍然发挥着不可替代的作用。     

The effect of runner blade loading on the performance and internal flow of a Francis hydro turbine model

As a core component of a hydropower station, hydro turbines play a vital role in the integration of a power station. Research on the technology of hydro turbine is continuously increasing with the development of water electricity. It is effective and successful to design a Francis turbine runner blade with good performance by one-dimensional hydraulic design method. For the one-dimensional hydraulic design, the runner blade angle at leading and trailing edges can be defined by calculation of Euler’s head. Design of the runner blade profile at several cross sections is needed to design a runner shape. In this study, there are three different blade loadings conducted to compare the internal flow characteristics and performance. The result shows that the front loading achieves the best efficiency in comparison to other loadings, which is good at suppressing the loss at draft tube.     

灯泡贯流式水轮机转轮内流场的研究

基于环形叶栅理论建立转轮叶片三维模型。采用FLUENT软件对转轮叶片进行了三维定常湍流计算。数值模拟了转轮内部三维湍流流场,得到了叶片表面压力云图、速度矢量图和叶片进出口边附近压力分布图,并估算出水轮机水力效率。结果表明采用环形叶栅理论建立的贯流式水轮机叶片具有可行性。     

水轮机模式液力透平叶片进口安放角影响分析

针对转轮叶片进口安放角β1对超低比转速水轮机模式液力透平性能影响规律认识不足的问题,在超低比转速范围内,考虑液力透平水力性能,取不同β1建立超低比转速混流式转轮三维模型,配合过流部件构建超低比转速水轮机模式二级液力透平模型,采用ANSYS FLUENT仿真软件对液力透平内部流动特性和能量特性进行计算,对比数值模拟结果,探求β1对超低比转速水轮机模式液力透平性能影响规律。研究表明,超低比转速水轮机模式液力透平的扬程和效率与β1有密切关系,当β1增大时,扬程增高,效率降低;随着β1增大,转轮叶片弯曲程度增大,导致叶片高压区面积增大、转轮内部流体流态变差。     

Application of the Modified nverse Design Method in the Optimization of the Runner Blade of a Mixed-Flow Pump

To improve the design speed and reduce the design cost for the previous blade design method, a modified inverse design method is presented. In the new method, after a series of physical and mathematical simplifications, a sail?like constrained area is proposed, which can be used to configure di erent runner blade shapes. Then, the new method is applied to redesign and optimize the runner blade of the scale core component of the 1400?MW canned nuclear coolant pump in an established multi?optimization system compromising the Computational Fluid Dynamics(CFD) analysis, the Response Surface Methodology(RSM) and the Non?dominated Sorting Genetic Algorithm?II(NSGA?II). After the execution of the optimization procedure, three optimal samples were ultimately obtained. Then, through comparative analysis using the target runner blade, it was found that the maximum e ciency improvement reached 1.6%, while the head improvement was about 10%. Overall, a promising runner blade inverse design method which will benefit the hydraulic design of the mixed?flow pump has been proposed.     

大型混流式模型机组动应力及压力脉动测试研究

最近几年在若干水力工程中,由于设计及机组运行调度的不合理,一些电站的机组,尤其是转轮叶片出现了局部裂纹问题,这引起了业界的高度关注。为此,东方电机在模型机组和真机上开展了叶片表面的动应力及表面压力脉动的测试。呈现模型机组测试的结果,通过这种测试发现最大的压力脉动幅值出现在转轮进口边区域,叶片表面上的压力脉动幅值明显大于转轮与活动导叶动静干涉所在的无叶区诱发的压力脉动幅值以及尾水涡所在的尾水管区域诱发的压力脉动幅值。叶片表面的压力脉动对应的主频和动应力对应的主频一致,主要为叶片数通过频率。动应力表现为类转频、尾水涡频率和动静干涉频率的叠加。     

汽轮机气动设计中的S2流面计算

本文介绍了基于S2流面上流函数气动方程反问题解法的汽轮机气动设计计算方法。可以与S1流面上的计算结合起来进行透平级的准三元设计计算;也可以在某些简化条件下单独使用,进行多级透平各排叶片扭曲规律的设计计算。基本方程采用任意非正交曲线坐标系,使用线松弛方法求解。以哈尔滨汽轮机厂优化20kW汽轮机低压缸为算例,将计算结果与轴对称假定下叶片间隙站内的计算结果进行了比较,并分析了叶片力、叶片厚度及熵的积累等因素对计算结果的影响。     

VIBRATION ANALYSIS OF TURBINE BASED ON FLUID-STRUCTURE COUPLING

The vibration of a Francis turbine is analyzed with the additional quality matrix method based on fluid-structure coupling （FSC）. Firstly, the vibration frequency and mode of blade and runner in air and water are calculated. Secondly, the influences to runner frequency domain by large flow, small flow and design flow working conditions are compared. Finally the influences to runner modes by centrifugal forces under three rotating speeds of 400 r/rain, 500 r/min and 600 r/rain are compared. The centrifugal force and small flow working condition have greatly influence on the vibration of small runner. With the increase of centrifugal force, the vibration frequency of the runner is sharply increased. Some order frequencies are even close to the runner natural frequency in the air. Because the low frequency vibration will severely damage the stability of the turbine, low frequency vibration of units should be avoided as soon as possible.     

INFLUENCE OF BLADES'''' STRESS STATE ON FRANCIS TURBINE RUNNER''''S INVALIDATION

Numerical simulation on Francis turbine runner's welding temperature field and welding tress field is carried out on the base of solving the problem of welding heat source's movement along any spatial routes and the problem of heat elimination between the complicated blade and air. The evolvement law of welding stress and the distribution of the stress field after welding are obtained. The results indicate that the peak value of the welding residual stress appears on the outlet edge of blade near the contact area between blade and band or blade and crown. Associated with the distribution of the runner's working stress, the invalidation reason of the Francis turbine runner is explained.     

Numerical simulation of pressure fluctuations in a large Francis turbine runner

The pressure fluctuation caused by unsteady flow in runner is one of the main reasons of vibration for a large Francis hydraulic turbine. It directly affects the steady operation of the hydraulic turbine unit. The existing research of the pressure fluctuation in hydraulic turbine mainly focuses on the unsteady flow in draft tube. Accurate distribution of pressure fluctuations inside a runner is not very clear. In this paper, the numerical method for predicting the pressure fluctuations in runner is investigated and the numerical simulation is performed for a large Francis hydraulic turbine. It is proved that the combination of shear-stress transport(SST) k-w turbulence model and pressure-implicit with splitting of operators(PISO) algorithm could give more reliable prediction of pressure fluctuations in runner. The frequencies of pressure fluctuations in runner are affected by the flow in guide vane and the flow in draft tube. The first dominant frequency is significantly determined by the flow in draft tube, especially at part load condition. This frequency is approximately equal to one-third of the runner rotating frequency. The evident second dominant frequency is exactly equal to the guide vane passing frequency. The peak-to-peak amplitudes of pressure fluctuations in runner at small guide vane open angle are larger than that at large open angle at the same operating head. The amplitudes at points on blade pressure surface are generally greater than that on suction surface. The research results could be used to direct the hydraulic design and operation stability improvement of a large Francis hydraulic turbine.     

Reconstruction methodology of a Francis runner blade using numerical tools

Journal of Mechanical Science and Technology - In a hydraulic turbine, the search of a better energy exchange with the fluid has led to designs of runner blade of geometrical shapes so complex that...