水泵选型应注意的几个问题

水泵的选型是动力机、传动及辅助设备等的配套、泵站工程建筑物的设计以及泵站经济运行的依据,水泵选型不合理不仅会增加工程投资,而且会降低水泵的运行效率,增加泵站能耗和运行费用。因此,水泵的选型至关重要。     

南水北调供水配套工程任坡泵站机组选型

文章简要介绍了河南省南水北调受水区供水配套工程16号分水口门任坡泵站水泵机组选型的过程。水泵选型的原则是在设计扬程下满足设计流量且效率最高,并兼顾到泵站的最大、最小扬程工况,水泵台数的多少直接影响到泵型的选择、泵站工程投资以及建成后的运行管理费用等。与水泵配套的电机其容量选择是否合适直接关系到整个泵站是否能够经济运行。     

灌溉泵站设计参数的确定及水泵选型

水泵选型是泵站工程设计中的重要问题,选型合理与否,直接关系到泵站工程的投资、建成后的运行费用和供水安全.水泵选型必须根据工程具体情况,确定合适的水泵型号和台数.选型的基本依据是泵站工程规划中所确定的设计参数,即所在泵站的流量、扬程及其变化规律.本文对灌溉泵站的设计参数确定及水泵选型问题进行了讨论,提出了设计参数的确定及水泵选型的方法.     

泵站工程水泵机组选型及水锤防护探讨

水泵是泵站提水加压的主要设备，水泵机组及配套附属设备的选型是整个泵站设计质量控制的核心。结合流量、扬程、输水介质及安装环境等影响因素，从水泵型式比选、运转工作点判定、机组台数组合和水锤防护等方面，对机组型式及参数选择的技术关键进行了详细论证分析，给出较优的组合方案以确保泵站工程具备较好的运行安全性和节能经济性。     

乐甲泵站水泵选型方案比选

大伙房水库输水应急入连工程是向大连市供水的长距离供水工程,其中泵站水泵选型方案的合理设计对节省工程的一次性投资、运行费用及方便工程运行管理等具有十分重要的意义。本文从技术和经济两方面对乐甲泵站水泵选型进行比较,最终选择较优的方案,为大连应急供水工程设计提供参考。     

丹寨吊洞水库供水工程一级泵站机组选型分析

每种型号水泵的运行扬程范围都是有限的,一般情况下水泵配套电动机转速一定,水泵输出流量会随扬程的变化而相应反向变化,若扬程变幅所占扬程本身大小的比例不大,不影响水泵稳定运行,反之则不能稳定运行,且达不到预计供水效果。当提水泵站扬程变幅较大时,应考虑使用水泵配套电机变频运行或分组选泵的措施。文章以丹寨吊洞水库工程一级泵站为例,对扬程变幅较大的泵站水泵机组选型进行论述。     

杨家杖子供水工程中途加压泵站水泵选型设计

水泵选型对于山区城市供水工程具有重要的意义。本文以辽宁省葫芦岛市杨家杖子供水工程为实例,基于中途加压泵站水泵运行工况,分析确定了该供水工程中途加压泵站水泵运行台数,并就水泵选型设计比选中的调速方式进行了探讨,进一步验证了三用一备全调速泵方案的合理性,以期对类似工程水泵选型有所借鉴。     

高扬程泵站机组选型设计探讨

水泵作为一种通用机械,广泛地运用于国民经济发展的各个环节,在农业和水利工程中尤为常用。对于高扬程、长距离的泵站工程来说,水泵能否高效稳定地运行是整个工程的关键核心技术问题。对某高扬程、大流量引水泵站工程,水泵选型时,各类泵型的技术参数及特点进行了综合考虑和分析,同时,对每种泵型所产生的经济成本进行了分析评价,根据分析、比选结果,从而确定了最适宜该工程的一种设计方案。该引水泵站的建成,有效地缓解了当地乡镇水资源短缺的矛盾,提高了乡镇农业生产、生活供水保证率,同时也验证了所选方案的正确性。研究成果可为类似工程的设计提供借鉴。     

粤西白沙泵站水泵选型设计

以粤西白沙泵站水泵机组选型为实例,根据泵站设计排涝流量、特征水位、设计扬程等参数以及选定站址的地形、地质等条件的要求,充分考虑技术可靠性和经济合理性,从技术、施工和工程投资等方面进行了分析、比较,以选择适合的水泵机组型号及台数,合理布置泵房结构.由于白沙泵站设计流量大、扬程低,因此主要是选取传统的轴流泵和大型潜水泵两种泵型进行比较.大型潜水泵为新型机电一体机,具有技术先进、机组结构紧凑、运行稳定及安装、检修方便等优点,且泵房结构简单、施工方便、经济合理,通过对泵站各运行工况的校核,水泵均可高效运行,因此,推荐粤西白沙泵站采用大型潜水泵.     

泵站工程设计中几个问题的探讨

泵站是水利工程的重要组成部分,深入研究泵站选址、工程布置、水泵选型、厂区设计、信息化建设等方面的问题,可以使泵站布局更加合理、使用效率更高、能源消耗更少、运行管理更加便捷。泵站信息化建设可以提高泵站自动化运行水平,为区域智慧水务平台建设提供基础数据,实现区域水利设施联合调度。     

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。