某锅炉减温器水管失效原因分析及预防对策

分析了某锅炉减温器出水管轴向弯曲和进水管横向开裂的原因,进行了现场调查、宏观检测、理化检验分析和应力计算。分析结果表明,进出水管与减温器集箱内部构件连接不合理、焊接处应力过高以及腐蚀疲劳是导致减温器水管失效的主要原因。此外,还就失效原因提出了相应的预防对策。     

铸钢冷却水箱

电弧炼钢炉炉门的冷却水箱,一般都采用钢板焊接结构。这种水箱的焊缝很容易开裂漏水,使用寿命很低。为此,我们采用了铸钢冷却水箱(图示为0.5吨铸钢电炉炉门水箱),其炉外平面部分用10毫米钢板焊接,在水箱两腿处留进出水管。铸钢水箱由于炉内侧无焊缝,使用寿     

锅炉过热蒸汽二级减温器损坏分析与处理

针对锅炉过热蒸汽二级减温器损坏情况,分析减温器喷管断裂及减温器筒体、管座产生裂纹的原因,采取了临时处理措施,并对设备进行改造,实现了优化。     

锅炉减温器喷头缺陷检验及原因分析

减温器是电站锅炉的重要组成部分,关系到锅炉能否安全可靠的运行,提供符合要求的过饱和蒸气,使得汽轮机能够达到理想的工作状态,然而由于减温器在制造和运行过程中的许多不确定因素,使得减温器喷头可能产生裂纹等缺陷,最终将导致减温器的减温水直接冲刷减温器联箱简体,这对锅炉的安全运行造成极大的威胁。本文主要分析了锅炉减温器喷头出现缺陷的原因,采用无损检测方法分析了减温器喷头潜在的危险因子。     

电站面式减温器辐射状裂纹成因分析及预防对策

针对同一台电站面式减温器连续两年在蒸汽引出管孔处出现辐射状裂纹,本文从面式减温器高温高压下的材料特性、理论应力计算和工作环境三个方面作了详细的分析和讨论,获得了蒸汽引出管孔处所承受的应力值,同时校核了电站面式减温器在实际运行过程中的结构强度,从而分析了面式减温器产生辐射状裂纹的主次因素,最后提出了相应的预防对策和改进建议。     

新型文丘里式喷水减温器的入口型线设计

根据喷水减温器的工作原理,结合几种减温器的典型结构形式,设计了一种新型文丘里式喷水减温器。该减温器可容纳大范围的蒸汽流量,提高了减温效率。同时蒸汽经过喷嘴处会产生卡门涡街,增加了水粒在蒸汽中的停留时间,使气液两相换热更加充分,减小吸收距离,节约管材成本。利用文丘里流量测量计相似原理对减温器的入口型线做了理论设计研究,通过探讨和分析,论证了新型文丘里式喷水减温器的合理性和可行性。     

锅炉减温器裂纹原因分析及改进措施

找出了锅炉喷水减温器产生裂纹的主要原因是结构设计和内套筒选材存在缺陷。对套筒和喷嘴的支撑结构、套筒与联箱的连接方式和套筒材料进行了改进,通过改进,减温器运行正常,达到了预期的效果。     

减温器管座焊缝裂纹的成因分析

对中压锅炉面式减温器管座焊缝裂纹产生的原因进行分析     

外力因素对风机叶轮焊缝裂纹的剖析

齐二机床集团有限责任公司动力安装公司拥有SHL20—13A水管锅炉十余台，其中20T锅炉引风机Y5—47—12N12D右90℃的叶轮，由于功率在90KW转数1480转／分在运行中经常出现热裂纹，有的沿焊缝中心完全开裂：有的是从半弧底部位开裂约15mm：有的几乎是四面成形，从两侧磨损开裂。我们经反复研究论证：风机速度外力对20g板产生副作用。使得焊缝在高温下由于外力作用而开裂。     

笛型管式减温器通用化设计思路

目前公司采用的笛型减温器,结构数据多样,生产组织困难,用户频繁反馈减温器出现泄漏,为提高生产效率,提升产品质量,现就笛型管式减温器通用化设计进行探讨。     

气化炉三维扫描测量与数据处理

以德士古气化炉耐火砖的内壁蚀损检测设备为基础,对采集到的点云数据做了进一步处理.通过对数据的筛选和剔除,实现了数据点的平滑降噪细化和精简.然后利用点云对整、网格划分和分色显示等方法,最终完成了内壁腐蚀情况的三维建模.重点讨论了点云数据的预处理及后处理的方法,并根据内壁耐火砖的腐蚀阈值,提出了一种气化炉内壁腐蚀区域的识别与分割方法.对耐火砖的腐蚀分析、气化炉的生产与维修提供了可靠依据,并在工程应用中获得了一致认可.     

Mass spectrometry analysis of the influenza virus

The role of mass spectrometry to probe characteristics of the influenza virus, and vaccine and antiviral drugs that target the virus, are reviewed. Genetic and proteomic approaches have been applied which incorporate high resolution mass spectrometry and mass mapping to genotype the virus and establish its evolution in terms of the primary structure of the surface protein antigens. A mass spectrometric immunoassay has been developed and applied to assess the structure and antigenicity of the virus in terms of the hemagglutinin antigen. The quantitation of the hemagglutinin antigen in vaccine preparations has also been conducted that is of importance to their efficacy. Finally, the characterization and quantitation of antiviral drugs against the virus, and their metabolites, have been monitored in blood, serum, and urine. The combined approaches demonstrate the strengths of modern mass spectrometric methods for the characterization of this killer virus. [This article was published online 10 September 2008. An error was subsequently identified. This notice is included in the online and print versions to indicate that both have been corrected 7 November 2008.]     

Histochemical and ultrahistochemical localization of heavy metals in calf organs

Cadmium, zinc, selenium, and copper were administered, singly or in combination, orally or subcutaneously. Experiment I included 32 calves of both sexes; six received Cd (two groups), Zn, Cd, and Zn, and Cd and Se (two groups) and one group was a control. In Experiment II (21 bulls), three were given Cd, Cd, and Cu, and Cd and Zn, respectively, and one group was a control. For light microscopy, in Experiment I the highest amounts of silver granules were present in the samples of liver, small intestine, and vesicular gland of all the exposed groups; in Experiment II the most affected organs were liver, kidney, and small intestine. For electron microscopy, in Experiment I, after administration of Cd and Zn, the highest amounts of granules were seen in the cytoplasm of hepatocytes and cells of the proximal and distal renal tubules and the lowest amounts were found in glandular cells of the pancreas. Administration of Cd and Se resulted in the presence of large numbers of granules in the nuclei and nucleoli of spermatogonies. In Experiment II, ingestion of Cd and Zn in feed led to the appearance of highest amounts of granules in the nucleoli, nuclei, and cytoplasm of cells in testes, kidneys, and pancreas. Following Cd intake, the highest accumulation of granules was observed in the nucleoli of hepatocytes and cells of the proximal and distal renal tubules. Combined Cd and Cu produced the highest number of granules in cells of the proximal and distal renal tubules and in the nucleoli and nuclei of germinal epithelium.     

软体足式机器人驱动、建模与仿真研究综述

软体足式机器人因其优越的移动性能及面对复杂地形的通过能力受到越来越多研究者的关注。由于受到材料性质、驱动方法及制造工艺等多方面的限制,如何实现软体足式机器人的创新结构设计,提升软体机器人的运动速度和负载能力是目前亟待解决的问题之一。综述从仿生结构与驱动方法的角度对目前软体足式机器人的研究发展进行了系统阐述。由于软体机器人多为连续变形结构,加之软材料的物理非线性和软结构变形的几何非线性,力学建模与仿真一直是软体机器人研究领域的瓶颈。梳理了目前软体机器人的主要建模理论,总结了软体机械臂的建模与控制方法,进一步将其拓展到软体足式机器人的系统建模中。介绍了传统商业软件的应用与物理仿真引擎开发的进展,分析了软体机器人虚拟仿真的主要方法,展望了软体足式机器人的应用场景与未来研究方向。     

DESIGN AND ANALYSIS OF NOVEL ACTIVE ACTUATOR TO CONTROL LOW FREQUENCY VIBRATIONS OF SHAFT SYSTEM

Aiming at providing with high-load capability in active vibration control of large-scale rotor system, a new type of active actuator to simultaneously reduce the dangers of low frequency flexural and torsional vibrations is designed. The actuator employs electro-hydraulic system and can provide a high and circumferential load. To initialize new research, the characteristics of various kinds of active actuators to control rotor shaft vibration are briefly introduced. The purpose of this paper is to introduce the preliminary results via presenting the structure, functions and operating principles, in particular, the working process of the electro-hydraulic system of the new actuator which includes a set of high speed electromagnetic valves and a series of sloping cone-shaped openings, and presenting the transmission relationships among the control parameters from control signals into the valves to active load onto shaft. The course of the work is dynamic, and a series of spatial forces and moments are put on the shaft to get an external resultant force to reduce excitations that induce vibration of shafts. By checking states of vibration, the actuator can control the impulse width and the interval of injection time for applying different control force to a vibration shaft in two circumference directions through the regulating action of a set of combination directional control valves. The results from simulating analysis and experiment show evidence of that this design can satisfy the case of active process of decreasing of flexural and torsional vibrations.     

不同因素对汽车传动离合器接合过程影响分析

离合器是汽车传动系统的重要组成部分,其接合过程直接影响到车辆起步性能和动力传递,并影响系统各单元的使用寿命。针对离合器接合过程的特点,对滑摩状态和接合状态进行动力学分析,建立系统的动力学模型;从滑摩功和冲击度两个方面对离合器接合过程进行评价,获取影响换挡品质的评价指标因素;根据动力模型和数学模型,基于Simulink建立离合器接合过程的分析模型;研究不同坡度及载重等因素对离合器接合过程中摩擦片的角速度、滑摩功及冲击度的影响,获取各因素的影响规律。结果可知:随着油门开度和油门变化率的逐渐增大,离合器接合角速度和接合时间都有所增大,接合过程产生的滑摩功也不断增多;随着起步坡度、载重的增大,离合器接合角速度逐渐减小,接合时间逐渐增大,接合过程产生的滑摩功也不断增多;分析过程和结果为此类设计提供参考。     

The effect of basic nitrogen compounds on the tribological performance of sulphurised olefin

The effect of the molecular structure of basic nitrogen compounds on the lubricating properties of sulphurised olefin has been investigated using a Timken tester. X-ray Photoelectron Spectroscopy (XPS) and Energy Dispersive X-ray Analysis (EDAX) were used to study the chemical states of sulphur and nitrogen on the rubbed surfaces and the reaction rates of sulphur and iron separately. It was found that the antiwear and friction reduction properties of sulphurised olefin are greatly influenced by the different molecular structures of the basic nitrogen compounds. A composite additive package containing basic nitrogen compounds with sulphurised olefin can produce either synergistic or antagonistic effects, due to the influence of the different molecular structures of the basic nitrogen compounds. XPS analysis revealed that a tribochemical protective film containing nitrogen and sulphur was formed on the rubbed surface. EDAX analysis indicated that the reaction rates between elemental sulphur and iron were influenced by the different molecular structures of the basic nitrogen compounds. It was found that the apparent reaction rates of elemental sulphur and iron are related to the tribological characteristics of the additive package.     

基于刚柔耦合的高方平筛动力学建模与振动模态分析

针对高方平筛和其上固结的柔性吊杆组成的动力学系统,进行了刚柔耦合的动力学建模和振动模态分析。将筛体—偏重块系统和吊杆分别作为刚体和弹性的可变形体,建立了筛体稳态圆振动方程和吊杆悬臂梁力学模型,总结出系统固有频率的计算方法。在此基础上,采用有限元方法对系统进行了模态计算和动力学响应分析。结果表明,理论模型能够很好地反映筛体与吊杆之间的动力学耦合关系;以理论分析为基础的载荷和边界条件的设置,使有限元仿真结果较准确地模拟了系统实际的振动特性。     

三种海上风力机支撑基础与船舶碰撞的动力响应分析

建立了5 MW海上风力机与船舶碰撞模型,采用非线性动力学理论,对比和分析3种海上风力机支撑基础在不同速度船舶撞击下结构的抗撞性能及塔顶的风力机响应特性。结果表明：相对于三角架基础和导管架基础,单柱基础海上风力机位移和加速度响应更加明显;碰撞过程中,不仅碰撞区域发生变形,而且管桩连接部位、斜撑杆交叉处也有较明显的应变产生,应在设计过程中对这些部位进行加固。由海上风力机支撑基础撞击深度和接触力可知,导管架基础的抗撞性能最好。     

增压器涡轮叶片疲劳蠕变寿命预测方法

根据径流式增压器涡轮的结构与工作特点,分析了涡轮叶片的载荷与应力空间分布特征;针对增压器涡轮由疲劳与蠕变交互作用引起的叶根断裂失效模式,研究了增压器涡轮叶片叶根的载荷与应力变化历程,建立了涡轮叶片叶根的载荷与应力描述方法;然后建立了增压器涡轮叶片叶根疲劳蠕变寿命预测方法及模型,并运用建立的模型对增压器涡轮叶片叶根进行了寿命评估。