锅炉汽水管道支吊架现场调整实例

本文简述了某300MW亚临界电厂在墙式再热器换管改造过程中,由于前期施工方案不够完善,导致在施工过程中出现问题,后通过对墙式再热器出口集箱及连接管上支吊架进行调整,最终使问题得以解决。     

蒸汽管道应力分析和支吊架调整

对某火力发电厂蒸汽管道进行了位移测量和应力计算,并依据计算结果对管道进行了支吊架的调整,结果表明支吊架的调整解决了管道运行存在的问题.     

支吊架附重对管系应力的影响分析

管道支吊架在火力发电厂四大汽水管道中主要承担承受管道荷载、限制管道位移和控制管道振动等作用。针对某300MW机组的再热管道系统,分析支吊架附属重量对管道一次应力和二次应力的影响,对考虑支吊架附重和不考虑支吊架附重两种情况对管道一次应力及二次应力影响进行对比,得出大型支吊架的附属重量在管道的应力分析中不容忽视,对管道的应力分布有较大影响。     

电站锅炉减温器缺陷的检验与分析

我省某电厂1025t／h电站锅炉，运行时间2．6×104h，2009年9月进行首次定期内部检验。该炉在屏式再热器出口集箱至高温再热器入口集箱之间的连接管道上安装有微量喷水减温器，减温器简体规格谚5588mm×25mm，材料12Cr1MoVG，工作压力361MPa，     

压力匹配器在某百万供热机组中的运用

为了提高国内某2×1 000MW机组供热的热经济性,以国家有关政策为原则,结合工程的热负荷要求及机组特性,在不同工况下对四抽减温减压供汽、高排与五抽压力匹配供汽、低温再热器出口集箱带动引风机小汽轮机背压排汽供汽、低温再热器出口集箱带动引风机小汽轮机抽汽供汽等四种供热方法进行技术和经济对比分析及压力匹配器原理分析,发现压力匹配器方案可靠性高,经济性好,能满足多种工况下的供热需求,最终推荐高排与五抽压力匹配供汽的供热方案。     

超超临界锅炉管座F92材料异常及处理

某电厂1000MW超超临界直流几型锅炉，一次再热，前后墙对冲燃烧，过热器出口蒸汽压力：27．46MPa，温度：605℃。高温过热器出口混合集箱、屏式过热器出口混合集箱、高温再热器的出口混合集箱以及与之连接的过渡管材、混合集箱上管座都为9Cr-2W钢，其中过渡段大小头、集箱管座的材质为ASTMA182F192，如图1，2所示。     

田集一次再热机组高温再热器出口集箱T92管座运行可靠性分析

针对田集发电厂二期3号锅炉再热蒸汽623℃锅炉高温再热器出口集箱T92管座的高温运行可靠性进行分析。从材料抗氧化性能和持久强度两方面进行了入手。可靠性分析表明,高温再热器出口集箱T92管座能够安全可靠运行,同时提出了相关跟踪保证措施。     

田集二次再热机组高温再热器出口集箱T92管座运行可靠性分析

针对田集发电厂二期3号锅炉再热蒸汽623℃锅炉高温再热器出口集箱T92管座的高温运行可靠性进行分析.从材料抗氧化性能和持久强度两方面进行了入手.可靠性分析表明,高温再热器出口集箱T92管座能够安全可靠运行,同时提出了相关跟踪保证措施.     

超超临界机组锅炉再热器减温水进水管开裂泄露原因分析及处理

锅炉再热汽温主要通过布置在尾部竖井烟道底部的烟气调温挡板调节.为适应变负荷或事故工况的需要,在低温再热器出口集箱与高温再热器进口集箱之间布置了4个事故喷水减温器.再热器喷水减温器频繁投撤时,再热器减温器进水管会出现热疲劳,甚至开裂.主要对再热器减温器进水管开裂原因进行了分析,并提出了控制措施,为其他电厂提供借鉴,可减少类似事故事件发生.     

管组集箱采用三通结构引入引出对锅炉再热器热偏差的影响

再热器蒸汽侧压降一般很小,集箱中的静压分布将是决定并联管屏流量分配的重要因素.当集箱引入管为三通结构时,在三通区域的集箱中存在涡流区,使该区域的集箱静压大大下降,造成这部分管屏流量偏小,热偏差增大,甚至导致超温爆管.本文根据实炉再热器的出口汽温分布特征,以及三通管流场和静压分布的实验结果,分析了屏间热偏差产生的原因,并提出减小屏间热偏差的改进方向.     

小型锅炉烟尘测试时锅炉出力的计算

锅炉烟尘测试时,必须对锅炉出力进行测试。但监测中,许多小型锅炉往往不具备相关的计量装置和仪表,为解决这一问题,文章提出了用烟气量和空气过剩系数来计算锅炉的出力的公式,在实际使用中,该方法简单易行,其结果和实测值具有很好的一致怀。     

Unerroric of control of mutual compliance of the efficiency of hydrogen engines of unmanned vehicles in the conditions of mass production

The issues related to the reliability of hydrogen engines of unmanned vehicles and increasing the efficiency of using hydrogen as fuel when using the method of its production during the decomposition of hydrogen-containing molecules of liquid-phase organic compounds in a plasma discharge under the action of intense ultrasonic exposure are considered. Experiments have shown that as a result of decomposition in the acoustoplasma discharge of liquid hydrocarbons, solid-phase carbon-containing products are formed, chemical transformations occur in the liquid phase and hydrogen-containing combustible gas is formed. Hydrogen-containing gas can be used as fuel immediately after synthesis, i.e. it does not require separation, since in addition to hydrogen it contains only impurities of CO₂ and water vapor. The purpose of the study is to formalize the basic conditions for tightening the control of mutual compliance with the efficiency of hydrogen engines of the same series in the conditions of their mass production. Methods of mathematical statistics and hardware-software modeling were used in the study. The term “unerroric of quality mutual compliance control” is introduced to describe a set of hardware and software tools for such control. The principle of in-depth testing of the technical condition of such engines of one series is described in a multidimensional formulation of the quality control problem for three of their operating parameters at once. The conditions for increasing the mutual correspondence of the measured values of such parameters in the conditions of serial production of hydrogen engines are formalized.     

中国煤炭地下气化技术的发展

本文综述了煤炭地下汽化技术的国内外发展现状,对我国“长通道、大断面”煤炭地下气化新工艺给予了技术经济评述,并提出了发展煤炭地下汽化技术的政策建议。     

Review of theory of distortion and disintegration of liquid streams

Linear and nonlinear analyses of the instabilities and distortion of liquid streams injected into a gaseous media are discussed. The various fundamental mechanisms and the predictive capabilities for the distortions are emphasized. Round jets, planar sheets, annular sheets, and conical sheets are discussed in detail. The balance between capillary and inertial forces is primarily examined. The method for simplifying the analyses in the case of thin liquid sheets is discussed. The capabilities for representing the droplet size distribution that follows the stream disintegration are outlined.     

MgO膨胀剂细度对MgO水化和水泥浆体膨胀的影响

基于《水工混凝土掺用氧化镁技术规范》中的Ⅰ型氧化镁（MgO）,研究了该型MgO膨胀剂（MEA）细度对掺粉煤灰水泥浆体膨胀性能的影响。即采用X射线衍射分析(XRD)及同步热分析（TG DSC）分析了掺MEA水泥浆体中MgO的水化性。结果表明,养护温度相同时,MEA的细度对水泥浆体内MEA中MgO的水化和水泥浆体的膨胀无显著影响,产生的膨胀均能补偿水泥浆体的收缩;MEA的细度可从试验设计采用的45 μm筛筛余15%左右增加到30%左右,这将有利于MEA生产企业的节能降耗。     

机车车轮多轴疲劳强度安全评定的研究

使用ANSYS8.0软件对高速列车车轮进行了三维有限元分析,计算出车轮在直线、曲线和道岔条件下牵引、制动共6种工况时孔边薄弱部位的应力,分别通过Mises等效平均应力方法、Sines平均主应力方法和应力分量中考虑平均应力方法计算出应力在极值位置时的等效应力幅、等效平均应力,从而进一步算出车轮的安全系数,对其疲劳强度进行评定,并对3种方法进行了比较研究。     

Constructal optimization of the geometry of an array of micro-channels

This paper documents the geometric optimization of an array of circular and non-circular ducts. The optimization was carried out numerically using finite volume method. As optimal dimensions were independent of the array configuration, the numerical simulation was performed on a unit cell. Numerical optimization for circular, square and isosceles right triangle cross-sections of channels was performed. Based on the results of this investigation, some correlations were proposed to predict the optimal hydraulic diameter and dimensionless heat transfer per unit volume. In addition to examining the effect of pressure drop on these parameters, it was showed that among the different geometries of this study, square cross-section has the most efficiency for a given volume. The numerical results of the present study were compared with approximate results reported in the literature which a good agreement was observed.     

固体热辐射Yong性能分析

本文对漫灰均温物体在常物性条件下对外辐射传热的Ｙｏｎｇ值计算建立了数学模型。通过与物体内能Ｙｏｎｇ公式的数值计算比较,得出了辐射能量的Ｙｏｎｇ值不大于内能Ｙｏｎｇ值的结论。从初步的热射Ｙｏｎｇ值计算公式发现。Ｙｏｎｇ与物体表面辐射率有关。     

Measurements of concentration distribution of hydrogen jet using deflection of center of the laser spot

The main purpose of this work is to propose a new method to evaluate the concentration distribution of the hydrogen jet by using a He–Ne laser through the jet. This research attempts to apply the expression of concentration Gaussian distribution, the refraction formula of inhomogeneous refractive index medium, and the concentration inversion function to disclose the displacement of the center of the laser spot at different heights in the gas jet. The spot images of the laser beam passing through the gas jet at three vertical heights z = 10d, 20d, 30d, and different radial positions are obtained. The radial spatial asymmetry of the gas jet is also found in the experiment. Finally, the calculated concentration distribution curve and the fluent simulation curve, it is found that the two results are very similar. Our findings show that the error between the concentration distribution of this method and the simulated concentration distribution reaches 2.43%.     

Heat of vaporization of mixtures

General expressions for the heat of vaporization of mixtures at constant pressure; at constant temperature; and at constant pressure, temperature, and composition are proposed. The last one is related to the liquid-vapor interface where steady vaporization or condensation is taking place. Numerical examples by the proposed expressions are shown for binary mixtures of HCFC22(R22) and (HCFC123(R123) © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25(1): 12–24, 1996