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在常规水电站供水系统优化设计中,机组技术供水系统采用清洁循环冷却水池的供水方案可避免泥沙的危害,还可减少机组技术供水设备的维修、维护工作量,有着一定的长期效益。阐述了该方案的适用条件、设置要求及优缺点。 相似文献
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老挝南湃水电站技术供水系统采用尾水取水单元供水方式,因电站所处流域河水中含有大量Ca、Mg离子,电站技术供水系统虽然设置有滤水器过滤,但是受水质条件影响,机组各部位冷却器(上导、下导、水导油冷却器及空冷器等)管内壁慢慢结垢,冷却效果下降,机组各部位温度上升,影响机组安全稳定运行。鉴于此,将技术供水系统改造为循环技术供水方式,以彻底解决冷却水水质问题。 相似文献
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闭式循环冷却器在机组技术供水系统中应用,省略了专门的水冷却处理设备,简化了系统规模,有利于节约用水和节约投资。通过实际投运的结果来看,不但达到了冷却机组各部轴承冷却用水的目的,还解决了机组冷却器及供排水管路泥沙淤积堵塞的难题。文章主要从闭式循环冷却器的性能、技术特点和运行,介绍了在小峡水电站技术供水系统中的应用情况。 相似文献
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水轮发电机组技术供水系统的主要作用是向机组的各导轴承及发电机空气冷却器提供冷却用水。以漫湾水电厂为例,对其机组的技术供水系统出现的问题展开分析。该水电厂机组的部分技术供水系统由于未与机组的开机、停机同步而处于常流水状态,造成了水资源的极大浪费。为此,经过分析研究,决定在机组技术供水总管的滤水器后加装电动阀,并将电动阀的控制接入到机组的自动开机和停机控制流程,实现了电动阀的自动开启或关闭。已完成改造的机组经过了近1 a的实际运行,运行效果表明,技术供水系统运行状态正常、可靠,水力损失得到了明显减少,电厂的自动化水平也得到了提高。 相似文献
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向家坝水电站技术供水系统采用单机单元自流减压供水方式,为避免长时间运行使冷却设备换热器管网内部淤塞,该水电站左岸厂房机组技术供水系统采用由四个水力控制阀组成的正、反向供水阀门组,以定期对管网进行正、反向冲洗,保证供水系统正常的冷却效果。 相似文献
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灯泡式水轮发电机的二次循环冷却系统的冷却水的冷却,多是通过炮泡体的冷却锥套表面与河水进行热交换的方式。石面坦、永兴、马骝滩、渭沱等水电站的灯泡贯流水轮发电机组,在刚投入运行时其发电机冷却 系统的冷却效果较好,但运行一段时间后,在其冷却锥套外壁都附着一层厚3-5mm的类似污泥或类似水垢的物质或水生物。对冷却锥套的热交换效果影响很大,致使发电机的运行温度升高,每年都需要组织人员进行清除。后经改造成敞开械循环冷却供水系统,取得了较好的效果。 相似文献
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赛珠水电站技术供水系统技术改造中,针对现场实际情况,经认真研究,对管路走向、设备布置和土建改造等进行优化.改造后,机组运行正常,技术供水系统各项数据满足技术要求,改造是成功的. 相似文献
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南津渡水电站机组冷却系统是引进奥地利ELIN的密闭循环强迫通风的冷却方式,运行多年实践证明冷却效果未到达国家相关技术标准。文章介绍了南津渡水电站冷却系统改造的技术方案、功能设计等,对国内同类型机组的改造有参考意义。 相似文献
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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。 相似文献
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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. 相似文献
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Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river. 相似文献
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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. 相似文献
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V. K. Konovalov O. V. Yashkin V. V. Ermakov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2008,42(2):105-109
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.
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Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008). 相似文献
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Peter B. Bayley 《河流研究与利用》1991,6(2):75-86
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. 相似文献