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借鉴水轮机尾水管水力设计标准化的成功经验, 为使优秀的前置竖井式贯流泵装置在我国低扬程及特低扬程 泵站得到更多更好地应用, 对前置竖井式贯流泵装置流道水力设计标准化进行了较为深入地研究。按满足工程应 用实际需要和分档方案不过于繁多的原则, 在常用值取值范围内对进、出水流道水力设计系列方案进行合理分档; 以竖井宽度和水泵名义平均流速为关键参数, 将进水流道划分为 24 种水力设计标准化方案; 以出水流道出口断面宽度和水泵名义平均流速为关键参数, 将出水流道划分为 17 种水力设计标准化方案; 经优化水力设计计算, 所述进水流道 24 种方案和出水流道 17 种方案的水力性能优异。前置竖井式贯流泵装置流道水力设计标准化研究工作在国内外尚属首次, 对提高低扬程泵站的设计水平具有重要意义。 相似文献
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大型竖井贯流泵站出水流道的水力性能分析 总被引:1,自引:0,他引:1
对于低扬程泵装置,出水流道的水力性能对水泵装置性能影响较大。以浙江省某大型竖井贯流泵站出水流道的设计资料为研究背景,根据出水流道的水力设计要求,将流道水力损失最小作为优化设计目标函数,通过确定流道控制尺寸和设计流道型线,给出了出水流道的两种设计方案。采用流道数值模拟方法,对两种设计方案分别进行了数值模拟计算和水力性能分析比较。分析结果表明,流道控制尺寸对流道水力性能和泵站土建费用影响较大,其值在允许范围内应尽可能小;流道型线影响流道水力损失,在控制尺寸一定的条件下,流道型线应进行细致的优化。 相似文献
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广泛应用于低扬程和特低扬程泵站的贯流泵装置,传统设计基本采用平直管出水的结构型式。针对城市防洪泵站扬程低、年运行时间短、安全性和可靠性要求高的特点,提出了5种新型虹吸式出水流道的贯流泵装置结构型式,它们具有结构简单、断流可靠、安装检修方便、维修和养护成本低等优点。在保持模型泵不变的情况下,采用CFD数值模拟技术,进行了不同结构型式的虹吸式出水贯流泵装置数值分析、优化水力设计和性能预测。根据优化设计结果,在高精度试验台上进行了虹吸出水和直管出水的竖井贯流泵装置模型对比试验。试验结果表明,两种竖井贯流泵装置的水力性能基本接近,平直管出水和虹吸式出水都是合适的低扬程泵站出水流道结构型式;在特低扬程情况下,采用虹吸式出水流道的泵装置结构型式具有更明显的优势。 相似文献
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我国低扬程泵站建设的水平经历了由低到高的发展过程,特别是南水北调东线一期工程的建设,促进低扬程泵站的关键技术取得了长足的进步;为进一步满足南水北调东线二期工程等重大工程大型低扬程泵站的需要,对南水北调东线一期工程低扬程泵装置水力设计的关键技术进行了较为系统的总结和提炼.结果 表明:南水北调工程水泵模型及水泵装置同台测试为保障我国低扬程泵装置水力设计质量作出了重要贡献;大型低扬程泵装置的水泵选型新方法可保证低扬程泵站设计扬程工况位于泵装置高效运行区、最高扬程工况位于稳定运行区;采用分层次优化水力设计方法可以有效完成低扬程泵装置流道优化水力设计工作;立式低扬程泵装置宜优先采用肘形进水和虹吸式出水流道;对于特低扬程泵站宜优先应用前置竖井贯流式泵装置,可满足结构稳定和水力性能优异的要求;为实现泵站工程整体最优化设计,需要采用泵装置水力设计与泵房水工设计、结构设计之间的协同优化设计方法. 相似文献
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经对南水北调长沟泵站肘型和钟型进水流道分别与平直管式、低驼峰式、虹吸式出水流道组合成10个装置流道方案,进行水力优化设计和CFD计算分析,优选出较佳的2种进水-出水流道与优选的2个转轮模型,再组合成4组泵装置,进行装置模型同台对比试验。试验所得最优泵装置即TJ04-ZL-06模型转轮配肘型进水流道-低驼峰出水流道,在设计工况(对应泵站平均扬程3.66、流量33.5m3/s)时装置效率达78.2%,综合性能达到了较理想的目标,大大提高了装置效率和叶轮中心安装高程,不仅减少了工程投资还节约了年运行费。 相似文献
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运用计算流体动力学方法,基于雷诺时均Navier-Stokes方程和标准k-ε湍流模型,针对通吕运河水利枢纽工程贯流泵装置特征扬程和设计参数对全流道进行数值模拟,在给定的水位资料和土建控制尺寸范围内,对竖井贯流泵装置进、出水流道进行了CFD分析和水力设计优化。通过对三种不同竖井宽度的进水流道内部流态分析、水力损失计算和泵装置效率预测,优选竖井最大宽度确定为5.4 m,该方案设计工况下进水流道水力损失为0.053 m。通过对三种不同出水流道设计方案内部流态分析、对水泵的效率影响和水力损失计算,上翘角对直管出水流道内部流态、水力损失和泵装置效率产生一定的影响,对比分析采用底部上翘角为3.56°的直管式出水流道具有较优的水力性能,且采用该方案时挡土翼墙高度可减少约1 m。竖井贯流泵装置内流CFD分析与进出水流道优化设计可为同类型泵站的设计提供优化参考。 相似文献
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流道对于泵装置的高效稳定运行具有至关重要的影响。为减小流道的水力损失并保证北坍泵站机组运行的安全稳定性,采用数值模拟技术对北坍泵站的肘形进水流道和低驼峰出水流道进行几何尺寸优化。通过对不同尺寸方案的流道水力性能进行分析比较,确定流道的优化方案并对最终优化方案组合的泵装置进行物理模型试验。结果表明:优化后肘形进水流道出口面的轴向流速均匀度提高0.10%,低驼峰出水流道水力损失降低23.91%。在不同叶片安放角(-4°、-2°、0°、+2°和+4°),模型泵装置的最高效率均超过72.00%;叶片安放角为+2°时,泵装置的最高效率为74.97%。在灌溉设计净扬程和排涝设计净扬程条件下,泵装置均保持高效率运行。优化后的泵装置水力效率和运行稳定性较高,可为同类型泵站的流道优化提供借鉴。 相似文献
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灯泡贯流泵装置的优化水力设计 总被引:4,自引:0,他引:4
采用CFD理论应用Fluent软件对某低扬程泵站灯泡贯流泵装置进行了三维湍流数值模拟及其优化水力设计,并采用透明流道模型试验验证了该优化设计.研究结果表明:灯泡贯流泵进、出水流道的控制尺寸及过流边界的形线对贯流泵装置的水力性能具有较为明显的影响;借助于三维湍流数值模拟方法可逐步优化其水力性能,且在设计流量下工作时的流道水力损失可控制在较小的范围内.前置灯泡贯流泵装置具有更好的水流条件,其水力 性能优于后置灯泡贯流泵装置.采用数值模拟得到的贯流泵装置流道的内部流态及其水力损失与流道模型试验得到的结果基本一致,表明采用数值模拟方法得到的灯泡贯流泵装置优化水力设计的结果是可信的. 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