某抽水蓄能电站地下厂房结构体系抗振研究

以某大型抽水蓄能电站为例,采用不同的地下厂房结构布置方案,即楼板采用板梁结构或厚板结构、上下游侧采用边墙结构或立柱结构、改变立柱结构的截面尺寸,提取结构的模态,分析了厂房结构的自振特性,并基于谐响应法分析了额定工况条件下不同方案之间动力特性的差异和楼板厚度敏感性。结果表明,在机组动荷载作用下,改变楼板结构形式或采用不同截面尺寸的立柱在一定范围内对厂房整体的自振特性作用有限;从厂房抗振角度来说,上下游侧采用边墙结构比立柱结构更有利;当厚板结构的厚度达到0.7m时,与现有板梁结构的抗振能力基本相当;就一般情况而言,板梁结构的抗振能力要高于厚板结构。因此,应结合工程实际情况来选择最优的结构体系布置方案。     

超静定结构在机车设计中的应用

用静力学平衡方程无法确定全部约束反力和内力的结构就称为超静定结构。在机车设计中恰当地运用超静定结构可以增大结构的刚度,改善结构中的应力分布,降低结构应力,从而提高结构强度和抗振性能。     

大型抽水蓄能电站不同楼板结构形式的动力特性研究

为研究不同结构形式下楼板振动特性的差异,在保证混凝土方量一致的前提下,设置板梁结构、厚板加圈梁结构和纯厚板结构三种形式,建立厂房三维有限元模型进行动力分析。结果表明,纯厚板结构的高阶自振频率高于板梁结构,而板梁结构略高于厚板加圈梁结构;在转轮叶片数频率及其两倍频率的脉动压力作用下,增加楼板厚度和板下增设梁系对绝大部分区域的楼板抗振是有利的,但三种楼板结构的振幅大致处于同一水平,不同结构形式有其抗振相对较强和相对较弱的部位,不存在绝对的最优方案。因此,实际工程中应综合考虑结构静力刚度、施工难度和管线布置等因素选择具体的楼板结构形式。     

四层砖混结构1/3缩尺模型模拟地震试验设计与研究

为研究砖混结构在地震作用下的破坏机理和抗震性能,对四层砖混结构建立缩尺模型,并进行相似关系论证,满足试验要求后对四层砖混结构建筑进行模拟地震振动台试验,观测结构在地震中的反应,并测得结构阻尼比、自振频率、加速度放大系数、位移时程曲线。试验结果表明,缩尺模型能准确还原地震中结构的破坏过程并测得有效数据,结构薄弱部位按破坏程度从强到弱依次为底部框架与上层砌体转换部位的构造柱、承重墙、底部框架梁柱节点部位;砖混结构在地震中,楼层连接处受损严重,各构件的结合方式对结构稳定性起着至关重要的作用。因此可适当改进砖混结构房屋的延性,采用楼板现浇等方式能有效增加砖混结构的抗震性能。     

“马蹄莲”形高层组合结构的动力特性及地震响应分析

为分析“马蹄莲”形高层组合结构的动力特性及地震响应,以武汉未来科技城为例,建立了“马蹄莲”形主塔楼高层组合结构的三维有限元模型,分析了结构的动力特性,得到结构的固有频率及自振周期,给出结构前四阶振型,并采用时程分析法研究了塔楼整体的三维地震响应及组合结构的薄弱部位。结果表明,塔架结构为组合结构整体的薄弱部位;x方向为组合结构体系抗震弱方向;人工波作用于结构抗震弱方向的楼层间最大侧移与层高之比(Δu/H)小于规范限值,为复杂组合结构的设计和施工提供了可靠保证。     

矿热炉保护套的优化设计

针对现有矿热炉水冷保护套的结构不足,提出一种新型的矿热炉水冷保护套结构,并采用流体有限元分析软件FLUENT对新型水冷保护套的结构进行优化设计,最终提出一种合理的结构,该结构在实际应用中取得了良好的效果。     

某泄洪水闸上部结构动力响应分析

大量震害表明水闸上部结构是地震作用下易发破坏部位,然而规范并未对其抗震性能作专门要求,众多水闸设计中并未将上部结构与主体结构作为整体分析。以西北某水闸为例,采用动力时程法分别计算了水闸整体结构、下部主体及上部结构的动力响应,对比分析了各个结构的动力响应,探讨了上部结构与下部结构之间的相互作用。结果表明,相比于单独承受地震作用,上部结构和下部结构作为一个整体时,水闸会出现显著的鞭梢效应,且下部结构的地震能量会向上部转移。建议水闸设计时考虑上部结构的影响。     

城市轨道交通车辆轻量化司机室结构研究

介绍了城市轨道交通车辆对司机室结构的要求,分析现有结构的优缺点,提出新材料碳纤维复合材料司机室及新结构全铝合金结构司机室,并提出实施方案。     

电站锅炉炉墙结构的设计研究

从电站锅炉的经济性、安全性角度,说明提高锅炉炉墙密封和绝热的意义。电站锅炉炉墙结构的研究,分为密封结构和保温结构。详细分析锅炉的密封难点、炉顶的位移矢量及炉顶密封结构,有炉顶前交叉密封、辐射式再热器密封罩壳、高冠密封支承系统、穿顶管束密封结构、炉顶侧密封等结构;由保温材料的特性述及炉墙的保温结构和保温措施,分析了敷管式炉墙、集中保温等多种形式的保温结构。另外,还专门论述了炉墙结构中的重要部分——耐火材料及其各性能要求。     

基于大产能的管式PECVD设备推舟机构的结构优化与仿真研究

对管式PECVD设备推舟机构的现有结构进行优化设计,利用ANSYS软件对优化后的结构进行仿真分析,从而获取大产能条件下各组成部件形变最小时的推舟机构结构.首先,对固定座组件结构进行优化;然后,在固定座组件优化后的基础上,对碳化硅杆结构进行优化;最后,在采用优化后的固定座组件及碳化硅杆结构基础上,通过对光轴直径、碳化硅杆...     

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。     

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     

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%.