单导叶接力器导叶不同步原因分析及故障处理

广州抽水蓄能电厂二期的水泵水轮机为高水头、大容量、高转速的混流式可逆机型。采用单导叶结构可以简化导水机构布置,提高单个导叶的可控制性。经多年检修经验得知,导叶不同步故障是导水机构故障的主要原因之一,从多个方面分析了导叶不同步故障的原因及解决方法,对导叶不同步故障的原因分析及处理有一定指导意义。     

灯泡贯流式机组导叶外环磨损原因分析及处理

导水机构作为水轮机重要组成部件,导水机构的运行状态影响着整个机组的稳定及安全。控制环在整个导水机构中起着传递导叶开度的作用,其中控制环与导叶外环直接接触,导叶外环承载着控制环的转动力矩及摩擦力矩,导叶外环在水电站日常运作当中发挥着不可替代的作用。它的状态正常与否将决定着机组的稳定性及安全性。因此做好水电站导叶外环的检修及日常维护工作十分重要。本文主要以导叶外环的磨损故障为例,分析可能产生磨损的原因,提出有效的解决办法及预防措施,以保证机组的安全稳定运行。     

抽水蓄能机组单导叶控制调速器常见故障模式及维护策略

结合多年抽水蓄能机组运维经验,对单导叶控制调速器各种故障模式的识别方法、预防措施、故障处理等进行深入分析,制定对应的维护策略,以减少故障发生的概率,充分发挥单导叶控制调速器的优点。广蓄B厂针对近年来单导叶控制调速器发生过的故障制定的维护策略具有针对性,取得较好效果。     

广州蓄能水电厂B厂机组导叶轴套选型研究

广州蓄能水电厂B厂4台机组自投产以来,多次出现导叶轴套漏水、损坏等问题,尤其8号机组频繁出现G工况启动时导叶拒动故障。通过综合比较分析,决定后续机组大修选用500SP1-SL464铜基镶嵌自润滑轴套替换500SP1-SL401轴套。8号机组于2012年2月完成大修,从实际运行情况来看,目前导叶轴套未发现漏水,导叶静态试验中导叶开关顺畅,机组小修时检查上下抗磨板无摩擦痕迹,导叶端面间隙正常无变化。     

水轮机导水机构的结构改进设计

现有的水轮机主要采用连杆式导水机构。为简化结构同时减少原材料的消耗,降低生产和制造成本,取消其连杆组件,将连杆式导水机构改为滑块式导水机构,由控制环直接带动导叶臂转动,调节导叶开度,以控制水轮机的流量。该结构简单、新颖,安装、维护方便,实用性强,提高了生产企业和电站的经济社会效益。图6幅。     

水轮机导叶摩擦装置的设计研究

在水轮机组运行中,导水机构通常是利用导叶臂与连板间的剪断销起过载保护作用,在控制环带动活动导叶向关闭方向运动,某些导叶发生卡阻,外力大于正常的关闭力一定值时,相应剪断销就会被剪断。目前有些机组则采用新型的导叶摩擦装置。文章介绍了导叶摩擦装置的主要结构和工作原理,提出了导叶摩擦装置设计时的主要参数,如压紧螺栓的直径大小、压紧螺栓预紧力矩大小的计算方法。     

长洲水利枢纽水轮发电机组重锤关机装置简介

重锤关机作为灯泡贯流机组最有效的防飞逸措施得到了广泛的应用,且重锤关机装置具有多种型式,各有特点。该文针对长洲三个主机厂生产的灯泡贯流式水轮发电机组,介绍其重锤关机装置的原理及主要特点。其中,A厂机组采用单作用导叶接力器模式,B厂采用双作用接力器结合事故配压阀模式,C厂机组采用双作用导叶接力器模式。当机组因事故甩负荷遇调速系统故障而不能正常关机时,三种装置均能实现安全关机,能有效地防止机组飞逸。     

龚嘴水电站机组导叶传动机构的结构改进与技术改造

对龚嘴水电站不同历史时期机组导叶传动机构的结构特点、运行情况进行了分析、比较,为上世纪60、70年代投产机组导叶传动机构的结构改进和技术改造提供了借鉴和参考.     

几种灯泡贯流式机组导水机构工装简介

导水机构是灯泡贯流式水轮发电机组的重要组成部分,主要由外配水环、内配水环、导叶、传动机构、调速机构等部件构成,其主要功能是使水在进入转轮前产生水流环量,并根据机组功率的需要开关导叶调节水流流量,达到预定的出力,水轮机停止运行时,导叶分段关闭切断水流。根据导水机构的结构特点,单支导叶具有各自的传动、调速机构,安装工序较为复杂,单个导叶系统安装调整完毕后方可进行整体的组装,为了提高安装质量及安装效率,介绍几种实用的导水机构工装。     

抽水蓄能电站导水机构的安装施工技术探析

导水机构是水泵水轮机的关键部件,运行环境较为复杂,主要是由导叶、导叶传动机构、导水机构接力器和项盖、底环、控制环等一系列部件组成。根据抽水蓄能电站导水机构的安装程序与技术要点,以海南琼中抽水蓄能电站导水机构安装施工为例,确定导水机构安装工作内容与流程、导水机构安装施工。导水机构安装施工主要包括底环、导叶、顶盖、控制环、拐臂和接力器的组装和安装。最后,提出施工质量保证措施,可为抽水蓄能电站导水机构的安装施工提供保障。     

SPATIAL AND TEMPORAL WATER QUALITY VARIABILITY IN AQUATIC HABITATS OF A CULTIVATED FLOODPLAIN

The floodplains of lowland rivers contain diverse aquatic habitats that provide valuable ecosystem services but are perturbed when intensively cultivated. Hydrologic, water chemistry and biological (fish) conditions in five aquatic habitats along the Coldwater River, Mississippi, were measured for more than 4 years: the river, two severed meanders that functioned as backwaters, a managed wetland and an ephemeral channel draining cultivated fields. Off‐channel habitats were connected to downstream regions 0.10% to 32% of the dry season and 24% to 67% of the wet season. The median temperatures for the five monitored sites ranged from 18°C to 23°C, the median total solids concentration for all sites was 135 mg L^?1, the median total phosphorus was 0.29 mg L^?1 and the median total nitrogen was 1.56 mg L^?1. Chemical and physical water quality displayed strong seasonal differences between the wet winter/spring and the dry summer/fall periods so that temporal variation consisted of gradual seasonal trends superimposed on strong diurnal variations. All off‐channel habitats exhibited periods of hypoxia and temperatures >30°C during the dry season. Between‐site gradients of water and habitat quality were strongly coupled to water depth and runoff loading. The rehabilitation of one backwater by increasing water depth and diverting agricultural runoff was associated with improved water quality and fish species richness relative to an adjacent untreated backwater. The diversion of polluted runoff and the use of water control structures to maintain greater water depth were observed to be effective management tools, but the former reduces the water supply to habitats that tend to dry up and the latter reduces connectivity. Published in 2011 by John Wiley & Sons, Ltd.     

Spatio‐temporal variation of gross CO2 and CH4 diffusive emissions from Australian reservoirs and natural aquatic ecosystems,and estimation of net reservoir emissions

Carbon dioxide (CO₂) and methane (CH₄) diffusive emissions were measured during two field surveys in Queensland and Tasmania, Australia, using the floating chamber method. Bubbling and degassing emissions in 2010 were estimated in Koombooloomba Dam reservoir using only inverted funnels and gas concentrations, respectively. A total of 14 reservoirs and 16 rivers and lakes were sampled from 2006 to 2010. Spatial variation was substantial within each water body, as well as between them. The main drivers of diffusive emission variation were physiographic region and climate, with a clear demarcation being observed between diffusive emissions from tropical Queensland and temperate Tasmania, and between the humid West Coast Range (Tasmania) and dry Central Plateau (Tasmania). Higher CO₂ and CH₄ diffusive emissions were observed during the dry season, when long water residence times would promote organic matter degradation. Estimated total gross emissions, including diffusive, bubbling and degassing emissions, for Koombooloomba Dam reservoir were about 1.5 × 10⁶ t CO₂eq km² per year, or 24 × 10⁶ t CO₂eq per year. This corresponds to a plant emission factor of 3.18 kg CO₂eq MWh^?1. Using an estimate of terrestrial emissions derived from literature data for the Tully River catchment area, rough estimated net emissions from the catchment area are about 44 kt CO₂eq per year, or 5.83 kg CO₂eq MWh^?1, which is in the lower range of the studied reservoirs.     

Serial discontinuities in a Rocky mountain river. II. Distribution and abundance of trichoptera

River regulation in the headwaters and middle reaches of the Gunnison River, Colorado, significantly altered distributions and abundances of Trichoptera fauna. Twenty-five species were collected from mainstream samples, with the greatest species richness occurring at an unregulated, rhithron segment above the central reach dams. At sites immediately below the three hypolimnial-release dams and a reregulation dam, species richness was reduced 35–90 per cent and abundance > 95 per cent. Net-spinning caddisflies were the dominant trichopterans at unregulated sites; Arctopsyche grandis in the upper reaches (218 organisms, 586 mg dry mass m^?2) and Hydropsyche cockerelli, H. occidentalis and Cheumatopsyche pettiti in the lower river (9041 total organisms, 6621 mg m^?2), downstream from the last dam. The observed distributional pattern of low trichopteran densities in dam tailwaters and high hydropsychid densities at sites 60–80 km below the central reach dams is a classic expression of continuum resets and adjustments in response to stream regulation as predicted by the Serial Discontinuity Concept.     

Surveying for Water Resources

Abstract

A professional Land Surveyor (Geomatician) describes the Hydrogeologists' survey requirements of a major water resources assessment for the government of The Sultanate of Oman (1992 to 1996). The need for objective specifications is stated. Specialist terms like geoid, spheroid, Mean Sea Level are explained and how to relate spheroidal levels to the geoid. Methods like traditional survey, satellite survey, and photogrammetry are introduced. The paper encourages coordinated working for the benefit of water resource assessment and recommends employment of the professional land surveyor for major studies.     

The Impact of Economic Development on Water Pollution: Trends and Policy Actions in Malaysia

The paper examines the impact of development activities on water pollution in Malaysia. Hence, the main objective of this paper is not just to examine the trends of development-induced water pollution around the region of the country but to know where the problems are and the policy measures taken by the government. It evaluates the probable causative relationship between problems introduced due to technology employed in water pollution control and governmental policy measures. It examines the relationship between development indicators as sources of pollution and polluted rivers over a period of 12 years. The findings of the paper have shown that despite the policy enforcement actions against the identified sources of water pollution, all the three development indicators (chosen based on those identified sources) still accounted for high percentage of river pollution in Malaysia. The findings of the paper were used to identify the central fact of the location of the problem. Some crucial conclusions of where the problems likely to be, as reflected in the findings, are: (a) the issue of interactive-effects between pollutants that many policy-makers are not aware of. This is when policy measures concentrate only on one source of water pollution; (b) the enforcement strength and/or effectiveness of policy measures themselves; (c) financial constraints to invest in appropriate technology especially sewerage systems for controlling human source of water pollution in the country; as well as those confronting small polluting industries (d) finally, lack of cooperation between government and private business firms to comply with regulatory policies for water pollution control.     

Intangible Flood Damage Quantification

Flooding is a natural disaster that may cause tremendous tangibleand intangible damage to the national economy. The tangible damage assessment, i.e. the monetary value of all direct and indirect physical damages, has already been studied, whileintangible damages have not yet been taken into account. Thisarticle, therefore, is the first systematic attempt to assess bothtangible and intangible damages. The new proposed Anxiety-Productivity and Income Interrelationgship Approach (API) has been developed to quantify the intangible damage in monetary terms. The Bangkok area has been selected as the research area because several severe flood events have occurredthere over the last two decades. The 1983 Bangkok flood caused 6600 million baht in damage, according to estimates by the National Statistical Office (NSO). This article examines the totalflood damage (including the intangible damage) at different flood magnitudes. Case studies with and without flood mitigation projects are studied and compared. Furthermore, thisarticle also discusses the improvements over the conventional approach offered by the new API methodology.     

Seasonal variation in nutrient retention during inundation of a short‐hydroperiod floodplain

Floodplains are generally considered to be important locations for nutrient retention or inorganic‐to‐organic nutrient conversions in riverine ecosystems. However, little is known about nutrient processing in short‐hydroperiod floodplains or seasonal variation in floodplain nutrient retention. Therefore, we quantified the net uptake, release or transformation of nitrogen (N), phosphorus (P) and suspended sediment species during brief periods (1–2 days) of overbank flooding through a 250‐m floodplain flowpath on the fourth‐order Mattawoman Creek, Maryland U.S.A. Sampling occurred during a winter, two spring and a summer flood in this largely forested watershed with low nutrient and sediment loading. Concentrations of NO increased significantly in surface water flowing over the floodplain in three of the four floods, suggesting the floodplain was a source of NO. The upper portion of the floodplain flowpath consistently exported NH, most likely due to the hyporheic flushing of floodplain soil NH, which was then likely nitrified to NO in floodwaters. The floodplain was a sink for particulate organic P (POP) during two floods and particulate organic N and inorganic suspended sediment (ISS) during one flood. Large releases of all dissolved inorganic N and P species occurred following a snowmelt and subsequent cold winter flood. Although there was little consistency in most patterns of nutrient processing among the different floods, this floodplain, characterized by brief inundation, low residence time and low nutrient loading, behaved oppositely from the conceptual model for most floodplains in that it generally exported inorganic nutrients and imported organic nutrients. Published in 2007 by John Wiley & Sons, Ltd.     

浅淡溢洪道改扩建方案与选择

溢洪道改扩建和进行溢洪道方案布置，要择优选取溢洪道进口型式、防冲消能工，以使其工程量省、施工快、运行管理方便     

Experience in the Introduction of Steam-Water-Oxygen Cleaning, Passivation, and Preservation at the TÉTs-23 Cogeneration Plant of the Mosénergo Company

Conditions of the process of steam-water-oxygen cleaning, passivation, and conservation (SWOC, P, and C) of internal heating surfaces of the boiler and the high-pressure feed heater (HPFH) piping over the steam side are presented. The process produces partial cleaning of the internal heating surfaces from scale and yields a corrosion-resistant protective film that hinders corrosion processes both in the operation of the boiler and in the idle period.     

钢筋混凝土三点弯曲梁断裂韧度计算模型

基于虚拟裂缝模型,针对钢筋混凝土试件在三点弯曲作用下开裂截面的受力特征,在合理假定的前提下,给出了一种计算钢筋混凝土三点弯曲梁的失稳断裂韧度的解析方法。然后,应用该方法计算了初始缝高比α0(初始裂缝长度与试件高度的比值)分别为0.2,0.3,0.4,0.5的三点弯曲试件的最大荷载和临界有效裂缝长度,进而求得了钢筋混凝土三点弯曲梁的失稳断裂韧度。通过对计算结果与试验数据的误差分析,发现失稳断裂韧度最大误差为4.915%,说明这种方法可以较为准确地预测三点弯曲梁的失稳断裂韧度。在此基础上研究了初始缝高比α0对失稳断裂韧度的影响,发现失稳断裂韧度基本上不随α0变化,失稳断裂韧度可以作为材料常数,应用于裂缝扩展状态的判断。