水力模型在某区供水管网优化方案分析中的应用

为优化某城市供水管网系统,建立某区供水管网微观模型并进行校核;对供水管网运行状况进行模拟,分析配水系统区块化及节能改造后的效果,并用该水力模型对管网改造方案进行模拟计算。结果表明,区块化及节能改造结果较好,管网改造方案可行。水力模型作为供水系统的研究平台,能够及时发现管网中存在的问题,可为管网结构优化提供参考。     

大型多支线供水工程的爆管水力过渡过程分析

鉴于爆管是危及大型供水工程安全运行的严重事故工况,基于瞬变流基本理论,结合超压泄压阀的工作原理,建立了地下埋管爆管工况的水力过渡过程计算分析数学模型,并提出了供水系统中最危险的爆管位置的确定方法。实例应用结果表明,该模型能反映爆管过程中管道内压力和流量的瞬变过程,确定的爆管位置具有合理性。     

基于LCC的农村供水管网多目标遗传优化

针对农村供水的特点,为提高供水工程的效果和效益、合理降低寿命周期成本,引入全寿命周期设计理论,提出了包括初建成本、运行成本及维护成本的农村供水管网寿命周期成本(LCC)计算公式,建立了考虑LCC、供水管网节点平均水头富裕度的多目标优化模型。运用精英保留策略的非支配排序遗传算法(NSGA-Ⅱ)对供水管网优化模型进行求解,并依据侧重点的不同为决策者提供3种典型管径组合方案。工程实例证明了供水管网优化模型合理性,应用NSGA-Ⅱ进行农村供水管网优化是可行的。     

基于智能优化算法供水管网减压阀布设位置的优化研究

针对供水管网系统中存在过剩压力的问题，提出在管网中安装一定开启度的减压阀，以各节点运行水压与各节点最小服务水头之差的平方和最小为目标，结合管网水力平衡约束、节点压力约束构建减压阀优化压力漏失控制模型，利用遗传算法对模型进行求解，并以东南沿海城镇供水主干管网为算例进行验证。结果表明，所提模型及方法有效、可行，且优化效果显著。     

基于HHT和SVM的供水管网爆管诊断模型研究

针对当前复杂供水管网泄水事故频发的现象,提出以管网发生故障时的瞬态水力数据信息为样本,采用Hilbert-Huang变换将故障样本信息从水压—时间的时域信号转换为压力幅值—频率的频域信号。分析选取频域信号中的主要特征值坐标作为支持向量机(SVM)的输入数据,并采用粒子群算法(PSO)对SVM参数进行优化,建立了基于HHT和SVM的供水管网故障诊断模型。实例应用表明,该模型在供水管网泄漏诊断中效果较好,从而验证了模型的可行性。     

基于HHT和SVM的供水管网爆管诊断模型研究

针对当前复杂供水管网泄水事故频发的现象,提出以管网发生故障时的瞬态水力数据信息为样本,采用Hilbert Huang变换将故障样本信息从水压—时间的时域信号转换为压力幅值—频率的频域信号。分析选取频域信号中的主要特征值坐标作为支持向量机（SVM）的输入数据,并采用粒子群算法（PSO）对SVM参数进行优化,建立了基于HHT和SVM的供水管网故障诊断模型。实例应用表明,该模型在供水管网泄漏诊断中效果较好,从而验证了模型的可行性。     

基于水力模型的供水管网区块化优化研究

为进一步优化配水系统分区,提出了一种基于多尺度分区算法的供水管网区块化优化方法。该方法考虑了供水管网系统的节点压力信息,改进了分区评价函数,并结合城市供水管网实际情况进行分区。以A市为例,利用EPANET建模器建立供水管网水力模型,在此基础上结合配水系统分区理念,将A市供水管网分为了11个区块。结果表明,分区后的供水管网实现了单独区域水量计量,缩小了查找漏失范围;管网压力更加趋于均衡,降低了漏失水量和产销差,使供水管网运行更加科学化、合理化。研究成果可为供水管网分区优化管理提供参考。     

苏州市高新区给水管网水力模型的建立与应用

以三高宏扬给水管网水力模拟软件为模型搭建平台,建立了苏州市高新区给水管网水力模型。选取部分监测管段与节点,从压力、流量角度对模型进行了校核。运用校核合格的模型模拟了管网现阶段压力、流速运行状况,并针对服务区域低压区、低速区分析了现阶段管网可能产生的问题,提供了改建的建议。结果表明,给水管网水力模型的建立能为供水企业相关的调度管理工作提供技术参考。     

结构机理与试验辨识结合建模的城市供热二级网仿真

针对我国城市供热管网二级网水力平衡调节问题,提出采用结构机理结合试验辨识方法建立城市供热二级网管网仿真计算模型,通过现场试验方法辨识建筑物的阻力特性,结合图论算法对供热二级网流动状态进行仿真,指导全网水力平衡调节,为管网改造提供决策依据。选取胜利油田某热力站作为研究示范,根据建模仿真结果对该小区管网进行了改造,改造后全网水力平衡明显改善。     

DBS分区在北方某市供水管网压力管理中的应用

为了解决北方某市供水管网水厂出水压力不足、部分路段供水管网压力波动大、区域压力不均衡等问题,基于该市供水管网水力模型,综合考虑该市供水管网压力、水量、地形、行政管理区域等相关因素,对该市供水管网进行DBS分区。结果表明,该市管网实施分区管理后,A水厂供水负荷减小,用水高峰期出水压力不足问题得到解决;部分路段水压过高问题得到解决;各区块供水管网压力得到均衡。因此,DBS区块化管理在该市取得较明显效果,对改善供水管网管理水平具有一定的参考价值。     

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.     

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。     

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.     

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     

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。     

生物质催化热裂解技术的研究进展

生物质催化裂解是生物质热化学转化的一种重要途径。综述了生物质催化热裂解技术使用的反应器、催化剂类型,以及催化热裂解过程中热裂解温度、吹扫气、升温速率、生物质原料等条件的影响,展望了生物质催化热裂解技术的发展趋势。