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基于流固耦合数值方法的尾水涡带诱发尾水管振动分析 总被引:1,自引:0,他引:1
流体域运用切应力输运模型封闭时均化Navier-Stokes方程,固体域采用Newmark方法求解固体振动方程,流体和固体耦合作用面通过运动条件和动力条件考虑流固耦合作用,建立了尾水管-管内湍流流固耦合模型.进行了尾水管内部非定常周期性湍流计箅和尾水管本身涡致振动时程响应计算,并依据结果对尾水涡带和压力脉动的主要性质和尾水管振动特征进行分析.结果表明,建立的分析模型用于计算尾水压力脉动和尾水管振动响应是合理可行的,对于尾水管体形优化设计和水电站厂房结构的振动分析具有积极意义. 相似文献
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以某水电站弯肘形尾水管为研究对象,应用ANSYS软件建立从尾水管进口到尾水管出口过流部件的流道模型,划分网格后导入Fluent进行模拟计算。分析结果表明,在入口速度垂直进入时,尾水管内部的湍流动能变化不大,流动较为平缓,湍流发展较充分。随着速度入口夹角的增大,弯肘段入口及水平扩散段入口的湍流动能越来越大,即说明随速度入口夹角的增大,尾水管在弯肘段及水平扩散段的流动越紊乱,对机组稳定不利。该方法可预估弯肘形尾水管内部的流动性能和湍流发展程度。 相似文献
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梁兴 《河北水利水电技术》2011,(6):91-92
尾水管是水电站核心过流部件之一,结合尾水管初步设计的断面数据,利用UG软件进行三维空间建模,并对尾水管模型进行CFD计算,得出较满意的结果,论证了尾水管设计是符合电站实际运行要求的。 相似文献
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尾水管真空度是水电站设计和运行中重要的调保参数之一,在数值计算中,由于采用一维非恒定流的计算方法,只可能得到尾水管进口断面真空度的平均值,而模型试验时,可以测得尾水管进口断面不同位置的真空度.采用数值计算与模型试验相结合的方法,对清江水布垭水电站尾水管的真空度进行了对比研究,结果表明:模型测得的尾水管进口断面最小动水压力既包含水击压力的变化,又包含平行细铜管方向流速分量的变化;计算值介于边壁值和积分平均值之间,边壁压力不能代表断面平均压力,积分平均压力值包含流速水头,也不能真正反映水击压力的变化,所以建议还是以计算值为设计依据. 相似文献
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黄河龙口20 MW水轮机由于电站条件限制,不能按原模型尾水管进行换算。为满足电站尾水管的控制尺寸,重新设计了改型后尾水管,并对改型的尾水管进行了CFD及数值分析,证明改型后的尾水管在水力性能上优于原型尾水管。 相似文献
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本由普通尾水管根据电站控制尺寸要求改型成两种有中墩尾水管。按照来流条件分别计算了原型尾水管和两种有中墩的改型尾水管。基于CFD分析技术,对中墩的位置和体型进行了优化设计,并对其他不合理的地方进行了修型。优化设计结果显示两种改型尾水管都具有与模型尾水管相似的水力性能,并且改型方案二性能更优,达到了预期的目标。 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