汽轮机高压调节阀问题分析及处理

高压调节阀是调节汽轮机主蒸汽进汽量的机构,它能否正常工作,对汽轮机安全稳定运行起着至关重要的作用。现主要对某钢铁公司发电站汽轮机高压调节阀油动机现场行程测量连杆卡涩、油动机活塞抖动以及高压调节阀的输入值与反馈值偏差大等问题进行原因分析,并介绍了处理措施,处理后能确保汽轮机的正常安全运行及发电量不受影响。     

油动机快关缓冲系统的建模与仿真研究

汽轮机是火电厂和核电厂普遍采用的发动机,汽轮机必须在可靠的安全保障下才能运行,普遍采用油动机对汽轮机的运行进行调节和安全保护。大容量汽轮机对油动机快关功能有比较严格的要求,但目前在工程设计时缺乏合理的模型和设计方法,这成为研制大容量汽轮机系统中遇到的一个需要解决的问题,油动机的快关功能决定于其缓冲特性。以油动机的整个快关过程为研究对象,建立了圆锥形柱塞缓冲的数学模型,进行了不同缓冲结构参数下的油动机缓冲特性仿真及对比分析,为油动机缓冲结构的参数优化设计提供了理论依据。     

300MW机组引风机并列运行中振动故障诊断处理

某电厂300MW机组锅炉A、B引风机运行过程中存在振动波动现象,振动幅值、相位呈现相同的周期性.A、B引风机并列运行,两台引风机振动存在相互干扰的现象,即存在拍振,导致两台引风机并列运行状态下振动波动.在单台风机运行状态下,拍振现象消失,风机振幅、相位稳定.分别在单台风机运行状态下对A、B引风机进行现场动平衡,平衡后A、B引风机振动幅值在优良范围内且振动波动正常.     

循环流化床锅炉水位测量不准确的原因分析及整改措施

针对循环流化床锅炉水位测量过程中常出现的4个水位计测量信号偏差大的问题进行研究,对优化汽包水位测点安装方案、调整运行操作方法及消除信号干扰等方面进行整改。结果表明,改造后解决了水位测量不准确的问题。     

接插件密封圈破损的原因分析及改进措施

接插件广泛的应用于航空航天、汽车、电器等领域,是影响电气连接的重要部件,而密封圈是影响其防水防尘特性的关键零部件之一。某款商用车在市场上发现密封圈破损断裂的问题,通过对密封圈断口确定其失效形式,通过对整车运行工况、密封圈材质、接插件尺寸和装配过程排查,确定了造成密封圈破损的原因,并给出整改方案。一方面为以后出现类似的问题提供解决思路,另一方面对零部件设计提供指导。     

汽轮机组高调油动机系统快速关闭设计与试验研究

在分析汽轮机组油动机原理基础上,设计了油动机液压系统。以油动机快速关闭过程为研究对象,从缓冲机理入手,经过推导简化,将油动机快关过程分为局部节流损失,锐边节流和缝隙节流等三个阶段,列出了每一个阶段的活塞运动方程。建立了圆锥形、抛物线形和阶梯形柱塞缓冲的数学模型。通过对油动机测试,特别是对汽轮机安全运行的快关试验,为油动机的设计、生产及检验提供了可信的技术数据。     

引风机节能改造及性能试验研究

发电厂每台锅炉配备两台静叶可调子午加速轴流式引风机。投产后一直存在引风机运行效率偏低,能耗较高等问题。小修期间对引风机进行了改造。改造后试验表明,引风机效率提高了15%20%,节能效果十分显著。     

某国产亚临界660MW机组高调阀阀杆松脱的分析与改进

某汽轮机组各高压调节阀在机组运行过程中多次发生阀杆与连接杆连接处防转销断裂、阀杆脱落的缺陷,分析原因在于设备设计存在一定缺陷,检修工艺亦有不足之处。本文通过对调阀阀杆与油动机连接形式及调阀内部组件的改型,彻底消除了隐患。     

深度调峰下电站锅炉动调轴流引风机节能改造技术研究

在电站锅炉动调轴流引风机在设计之初,通常优先考虑中高负荷时引风机的运行经济性.在深度调峰政策背景下,由于中低负荷时引风机效率相对偏低,导致引风机电耗偏高.本文结合某电厂660MW超临界机组引风机性能参数和实际运行情况,根据现场测试试验结果,首先对引风机选型参数进行优化,并提出了引风机本体及电机改造的六种节能改造方案,通...     

1000MW火电机组汽动引风机启动并联运行方式探讨

驱动马达为小汽轮机的引风机与常规电动机驱动的引风机相比,其启动和并联具有特殊性。通过分析探讨可知,在引风机进口加补气门可保证单台引风机安全启动,在引风机进出口加烟气循环联络烟道可保证两台风机安全并联运行。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.