600WM汽轮机高压主汽门及高压调门DUMP阀故障分析与处理

介绍了DUMP阀的作用、结构原理,结合某电厂高压主汽门、高压调门几次故障案例,分析研究DUMP阀发生故障的原因,并提出相应的处理措施,为类似问题的解决提供了参考和借鉴。     

208C汽轮机主气阀泄漏故障浅析

本文针对汽轮机自动主汽阀内漏的问题,分别从设备结构、缺陷现象、处理过程等方面进行了分析总结。     

一起主冷泄漏故障的处理

介绍6500m3/h空分设备主冷泄漏经过,分析了主冷泄漏的原因,简述了处理措施和体会。为保证空分设备长期安全运行,避免加温时再引起类似故障,提出了相关建议。     

汽轮机叶顶汽封泄漏涡诱导下的压力脉动研究

以某汽轮机级为研究对象,采用三维非定常数值模拟的方法,研究了动叶顶部汽封泄漏涡的涡动特性和泄漏涡影响下汽封腔室内的压力脉动规律。结果表明:叶顶汽封腔室内存在周向螺旋状涡与壁角涡组成的多尺度涡系,涡系的位置和影响范围会随时间经历复杂的变化。叶顶汽封腔室内的压力脉动频率中兼具叶轮旋转的周期性频率和溃散为小尺度涡结构后的高频率。间隙内的多尺度涡结构和动静叶间交替变化的压力场在汽封间隙内的传播是引起汽封腔室内周向压力不均的主要原因。     

浅谈如何处理液压传动系统泄漏故障

液压传动系统泄漏是煤矿机械最常见的故障之一,在液压传动中,工作液体的泄漏是一个不可忽视的问题,如果泄漏得不到解决,不仅影响系统的工作性能,损坏液压元件,而且会浪费资源,污染环境,对安全生产造成威胁。该文通过对密封机理的研究,分析了液压传动的泄漏形式及原因,提出控制泄漏的措施。     

膨胀机增压后冷却器泄漏处理

35000 m3/h空分设备膨胀机增压后冷却器发生泄漏,气侧带水,使水分进入主换热器并堵塞部分换热通道,影响空分设备运行工况。为避免空分设备停机加温,采取频繁切换膨胀机运行,再对膨胀机进行加温的方法,将水分带出主换热器。介绍故障现象和具体的处理方案,阐述为杜绝类似故障再次发生而采取的优化措施。     

火电机组EH油管道泄漏典型案例分析及防范措施

汽轮机EH油系统管道连接供油系统、危急遮断系统与执行机构构成整个回路,其作为油介质的传输通道,一旦发生泄漏,将直接造成发电机组非计划停运,让企业蒙受巨大的经济效益与社会效益损失。针对某集团公司近期火电机组发生的多起EH油管道泄漏案例,从金属材料角度概括了EH油管道常见的几类失效机制,并结合每个典型案例,对失效分析过程及要点做了简单介绍,重点从技术监督角度提出了治理和防范措施,具体到相应的检查方法和检查内容,切合现场,以供借鉴。     

蒸汽辅助重力泄油双管壳体泄漏失效分析

某石油公司蒸汽辅助重力泄油注汽井在注汽过程中双管壳体部位发生泄漏。采用宏观检验、无损检测、化学成分分析、力学性能试验、硬度测试、金相检验、能谱分析和流场模拟等方法对双管壳体的泄漏原因进行了分析。结果表明:双管壳体泄漏主要是由流体冲蚀造成的,而副管压套与副管处的结构缺陷加速了冲蚀减薄进程。     

如何防范与处置汽轮机油箱油中带水

汽轮机油中带水严重时会危及汽轮机组安全的稳定运行,为此分析了气封间隙大、排烟系统、周封套、汽缸、轴承室负压等可能引起油中带水的原因,并分别提出了相应的改进办法。     

和谐3系列电力机车主变压器密封性的研究与油泄漏原因的探索和研究

本文从和谐3系列电力机车主变压器密封性的研究出发,根据其制造存在的油泄漏问题,对产生问题的原因进行了分析,研究和谐3系列电力机车主变压器在制造与使用环节产生油泄露的问题及原因,并提出具体可行的应对措施。     

The presentation of the nonsteady temperature field of a steam turbine rotor in generalized functions

Results of investigation into the possibility of expressing the temperature field of a turbine rotor in terms of generalized functions of temperature for use in the analysis of nonsteady thermal processes are presented.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 15, No. 6, pp. 1086–1092, December, 1968.     

The impact of host country regulatory quality on the value creation process in e-business supply chains

The use of e-business (EB) applications has reshaped an organisations’ supply chain structure. EB applications have enabled supply chain organisations to integrate their upstream and downstream supply chain processes to reach higher performance outcomes. Employing the resource-based view and contingency perspective as theoretical anchors, we propose and test a model of the relationship between EB applications, supply chain integration and financial performance that is moderated by a country’s regulatory quality. Cross-country data have been collected from 637 organisations through the International Manufacturing Strategy Survey research initiative. We hypothesise that the efficacy of the EB value creation process depends on the regulatory quality of the country that companies are located in. Results indicate that EB has a stronger impact on supply chain integration and supply chain integration has a stronger impact on financial performance, if the companies are situated in countries with high quality regulatory levels.     

The failure analysis of the repeat geartooth breakage in a 40 MW steam turbine load gearbox and the butterfly in the carburized case

A repeat premature geartooth breakage occurred in a load gearbox of a 40 MW steam turbine. Fractographic examination indicated that the fatigue crack originated from the root fillet of the non-active flank and propagated to the active flank. The oil deposit on the fracture surface has been applied as an auxiliary fractographic method to distinguish the fatigue crack path. The root cause of the fatigue failure was the improper heat treatment, including the very coarse microstructures due to the direct quenching from the carburizing, plus the shallow case and the insufficient surface hardness by the post-quenching grounding. The solution was successful. Some butterfly characteristics in this case study contradicted to the previous theories. The butterflies initiated from neither non-metallic inclusion nor carbide. The butterfly cracks did not propagate into the martensitic matrix. A butterfly observed in the subsurface of the gear-root indicated that the butterfly formation was irrelevant to the Hertzian stress.     

高强度聚焦超声消融滋养动脉治疗子宫肌瘤的临床价值

目的：探讨高强度聚焦超声消融滋养动脉治疗子宫肌瘤的可行性及有效性。方法：47例直径4~10cm肌壁间肌瘤,高强度聚焦超声治疗前通过彩色多普勒及超声造影确定肌瘤滋养动脉的蒂,对该区域进行消融,观察治疗前后肌瘤内部彩色多普勒及超声造影等影像学变化、随访临床症状及并发症。结果：治疗后肌瘤体积有不同程度的缩小,瘤体假包膜环状血流信号消失,肌瘤内部处于持续无灌注状态,部分患者临床症状消失或明显改善。结论：HIFU消融滋养动脉治疗子宫肌瘤能够缩短治疗时间,减少并发症,是一种微创和有效的方法。     

The analysis of the motive forces of sintering micro- and nanosized diamond powders at high pressure

It has been shown that in sintering diamond powders the summation of the Laplace pressure and external pressure acting on the system is not observed. The modeling of the shape of pores has shown that the cases are possible when capillary forces are directed in opposition to external forces. An expression is proposed that describes the limiting compaction of a system of diamond particles in this case. Experimental values of the density of diamond polycrystals sintered from diamond powders of various dispersions are well described by this equation within measuring error. To improve the sintering, additives that form chemical compounds with carbon and compound diamond particles in sintering should be used.     

超长大规格高强悬索桥主缆单元索股制造技术研究

以西堠门大桥国产1770MPa主缆索股制作技术为基础,进一步研究超长(≥4250m)大规格(≥169丝)高强度(1860MPa等级)主缆单元索股制造技术,同时对主缆索股的水平收放索技术和装置进行进一步的研究,为特大跨径悬索桥主缆单元索股的制造提供技术研究基础。     

The effect of composite damage on fatigue life of the high pressure vessel for natural gas vehicles

In order to examine how the damages such as scratches, cuts and gouges on the composite materials have effects on the fatigue life of NGV vessels, several experiments on real vessels were conducted and finite element analyses were applied. The flaw depths of COPV used in the experiments were 1.5 mm, 2.0 mm, 3.0 mm, and 4.0 mm, while the flaw lengths were 50 mm, 100 mm, and 200 mm. A flaw tolerance test defined by ANSI/IAS NGV2-2000 was performed on 12 vessels using a combination of these flaw depths and lengths. In the finite element analyses, stress analyses were performed using a commercial FEM program after the 3-D modelling of liner, hoop and helical layers by using MSC.PATRAN™. The result of the tests and analyses demonstrated that the effect of the flaw damages on the fatigue life of high pressure vessel for natural gas vehicles increases when the flaw depth is more than 3.0 mm and the flaw length is more than 100 mm.