不同转速水泵实现相同流量扬程的差异分析

从水泵效率、水泵引起的噪声、振动以及水泵造价等方面,分析了采用不同转速水泵实现相同流量扬程时的差异.建议在选择确定水泵转速时,结合水泵的使用场所、节能要求、造价等因素综合考虑,以选择合适的水泵转速和型号.     

橡胶坝充排水系统水泵选型设计研究

橡胶坝充排水系统使用水泵作为充坝、坍坝的动力设备,水泵选型的合理性是橡胶坝工程正常运行的关键。充坝时水泵的净扬程为正值而坍坝时水泵的净扬程为负值。因此,水泵选型时应充分考虑水泵在不同工况下净扬程对水泵选型的影响,合理计算确定水泵的扬程及范围,使选定的水泵运行在正常工况点范围内。     

供水泵站工程水泵选型计算实例分析

水泵选型计算主要受水泵特性曲线及管路系统特性曲线影响,水泵性能曲线表明水泵能在性能曲线上任一点所对应的工况下运行.水泵设计选型完成后,结合管道系统特性,需要找到不同工况下水泵的实际工作点,由此检验水泵和动力机选型的合理性.文章采用数解法对某泵站水泵运行的实际工作点进行推求,结果表明水泵和动力机选型合理.     

水电厂（渗漏）水泵控制系统优化调整方式研究

水泵控制系统在水电厂的防止水淹厂房事故中起到关键的作用，其中液位监测和水泵启停控制逻辑是水泵控制系统可靠的关键因素，对提高水泵控制系统的可靠性至关重要。以绿水河水电厂优化控制回路和液位监测技术为例，研究自动化技术的水泵系统原理，调整水泵控制回路以解决集水井抽水需求，实现水位测量与启停水泵的正确控制。     

怎样提高水泵效率

水泵效率是衡量水泵工作效能高低的一项技术经济指标。它是指水泵的有效功率（即水泵输出功率）和水泵轴功率（即水泵输入功率）之比。水泵效率一般在65％～90％，大型泵可达90％以上。水泵效率的高低，在很大程度上取决于水泵的使用情况，如果维修和使用不当，即使制造出高效率的水泵，也达不到高效低耗经济运行的目的。因此．在水泵实际运行中应尽力提高水泵效率．尽量减低在水泵把能量传给水的过程中，存在着的各项能量损失。一、减低容积损失。容积损失是指水在流经水系后所漏损的流量，包括从口环间隙，水泵填料密封和叶轮平衡孔等处所…     

大型泵站水泵安装高程的计算方法刍议

理论分析和实际运行表明,合适的水泵安装高程可以有效地避免气蚀(空)对水泵的伤害,而水泵气蚀仍是影响水泵安全的重要因素。近年来,有关设计部门高度重视水泵安装高程的选取,在模型试验成果和相关规程规定基础上,进行了适当的减低,较好的改善了水泵运行时的气蚀状况。因目前还没有一个针对水泵安装高程的定量计算办法,水泵安装高程如何取值存在着较大的争议。借鉴近几年专家学者的研究,在对在用的部分泵站气蚀状况统计分析的基础上,试图通过对水泵安装高程计算公式的修正,找出合适的水泵安装高程计算方法,进而为泵站设计提供参考。     

水泵出水压力不足故障分析与排除

水泵在更换同一厂家的叶轮后,出现压力不足,根本无法运行的情况.通过对电机电流、水泵吸程部分、水泵叶轮、电机转速等一系列检查检测后,发现水泵叶轮质量增大导致电机转速降低是使水泵压力降低的主要原因.通过互换1#、2#水泵叶轮,解决了压力不足的问题.     

大型立式单级双吸离心水泵的检修

根据不同情况和水泵本身出现的不同缺陷,大型立式单级双吸离心水泵的检修应采取不同的处理方法。以东江泵站水泵的检修为例,对水泵不同部位及相应的检修方法进行了介绍,以期能解决或预防水泵的缺陷。     

东方电机水泵水轮机水力开发的技术进步

从水泵水轮机水力设计技术、水泵水轮机模型装置设计技术和水泵水轮机模型试验技术等几个方面介绍了东方电机在抽水蓄能电站水泵水轮机水力研究开发上的技术进步。     

轴流泵站技术改造的探讨

针对江苏省国营淮海农场的轴流泵站存在的问题 ,即水泵扬程有的偏高 ,有的偏低 ,水泵高效区范围较窄 ,水泵装置不合理 ,提出了既经济又合理的水泵改造方案     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.     

基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。     

基于BP神经网络-马尔科夫链模型的隧道围岩位移预测

在隧道工程施工中,围岩位移预测起着很重要的作用。将BP神经网络-马尔科夫链模型引入到隧道围岩位移预测中来,通过对训练样本的学习,利用BP神经网络实现了对位移时间序列的滚动预测,同时得到了实测值与预测值的相对误差;在此基础上利用马尔科夫链对相对误差进行修正,有效地提高了预测结果的精度。并将该模型应用于某公路隧道拱顶下沉位移时序预测中,结果表明该模型具有精度高、科学可靠的特点,为隧道围岩变形的预测提供了新的途径。     

Short communication. Pipelines as a refuge for freshwater snails

In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment.     

浙江省水域调查录入系统的设计和应用

浙江省水域调查录入系统将调查数据与电子地图相整合,对分类水域数据进行统计计算,并对输入数据进行合理性和完整性检查,得到调查范围内现有水域的详细数据,实现了水域调查数据输入、计算、统计和查询的数字化管理,提高了工作效率和工作质量,为各地下阶段水域保护规划编制和水域管理工作提供了数据支持。对该系统的设计原则、功能和技术设计等作了介绍。     

基于CT-连续加荷水泥乳化沥青混凝土细观损伤规律研究

利用CT技术对水泥乳化沥青混凝土的细观损伤过程进行实时扫描观测,获得了混凝土试件在连续加荷下的CT图像。通过采用直观分析法、CT数分析法、CT数与损伤变量关系3种方法分析表明,水泥乳化沥青混凝土的破坏过程可分为压密、扩容、裂纹扩展、破坏4个阶段,同时混凝土在受压过程中具有韧性,在极限荷载之前各断面处于压密和微扩容的强化阶段,极限荷载之后混凝土从损伤到破坏发展比较平稳。     

Automated system for removal and pneumatic transport of fly ash from electric precipitator hoppers

A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system, configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants of dry ash utilization and the advantages of producing of size-separated particles are considered. __________ Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008).     

The flood pulse advantage and the restoration of river-floodplain systems

The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed.     

浅谈天湖水电站水轮机运行故障及处理措施

简述天湖水电站投运以来各种故障的表现形式，分析其原因，提出了相应的处理方法及措施，并对合理利用国内外设备提出建议。