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拟建的三峡枢纽水运新通道船闸末级闸室超长输水廊道运行水头高、输水量大、输水时间短、输水距离长,水流具有强非恒定性,保障其安全运行非常重要,故对高水头船闸末级闸首超长输水廊道的阀门开启过程的非恒定水动力特性进行数值模拟,研究不同输水廊道长度、不同阀门开启时间下,闸室流量过程、闸室水位过程、阀门井水位过程等水力要素的变化规律和影响因素。研究表明:船闸末级闸首输水廊道长度加长会增加惯性超降值、增长惯性超降波动周期、延长泄水时长、降低闸室水位升降速度,同时减少阀门开启过程中阀门井水位降落值;加快阀门开启速率会减少泄水时长、增加闸室水位升降速度、减少阀门开启过程中阀门井水位降落值。研究结果可供三峡枢纽水运新通道末级闸首超长泄水廊道设计参考。 相似文献
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针对南水北调东线胶东输水干线东平湖至济南段输水工程,建立水流模拟的水动力学模型。在对输水线渠道及众多水工建筑物概化的基础上,着重探讨建模过程中的5个关键性问题:①上、下游边界及初始条件处理;②进洪闸及分水闸的入出流过程处理;③新建渠道沿线渗漏量动态化处理;④输水线上倒虹吸、闸的过流量衔接模拟;⑤迭代求解中非线性方程过闸流量的解析化处理。最后,在假定的两种工况条件下进行模拟计算,结果表明沿线各断面计算水位、流量与设计水位、流量拟合较好,并指出工程运行后应根据实测水位和流量资料对已建模型作进一步调试。 相似文献
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输水交叉建筑物进出口段渗流异常成因存在不确定性。采用综合分析方法探讨某长距离调水工程一跨河渡槽出口段裹头渗漏的成因。在巡视检查和加固处理等资料分析的基础上,构建统计模型,定量分析渐变段渗透压力和底板扬压力与渠道水位、气温、降雨量等环境量的关系,判断渗流的主要影响因素;通过变形监测资料分析,结合工程地质和水文地质条件,判断引起裹头渗漏的原因;进而依据流场法、探地雷达和高密度电阻率法等地球物理探测方法揭示渗漏入口和通道等。综合分析认为,渗漏从渐变段末端结构缝进入,通过渐变段、闸室段和连接段的砂砾石层基础向裹头侧流出。考虑到该调水工程常年运行,渡槽难以停水检修,提出在闸室段增加灌浆帷幕截断渗流通道的防渗加固处置建议方案。采用的综合分析方法可为同类工程问题分析和处理提供参考。 相似文献
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在大流量输水工程中,水泵抽水断电后,管线往往会有较强的压力波动,易造成沿线水位压力较低。结合某大流量输水工程,建立了带连通阀的阻抗调压室数学模型,对比分析了简单调压室、阻抗调压室和带连通阀的阻抗调压室的水锤防护特性,验证了带连通阀的阻抗调压室的优越性,并研究了其连通阀关闭规律对调压室水锤防护特性的影响。研究表明:与简单调压室和阻抗调压室相比,带连通阀的阻抗调压室水锤防护效果更佳,可有效提高调压室最低水位和沿线最小压强,减小占地面积;水泵抽水运行断电后,连通阀须尽早关闭,且存在较优关闭速率。 相似文献
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Biochemistry of enhanced biological phosphorus removal and anaerobic COD stabilization. 总被引:1,自引:0,他引:1
Improved design strategies at BNR plants should include cost reductions so that the consumers and water authorities will be more willing to build EBPR plants instead of conventional activated sludge plants. Through efficient design, actual savings in construction and operation costs can be realized. For this reason, anaerobic stabilization of COD needs to be seriously considered during design for direct energy savings at the plants. The existence of anaerobic stabilization has been demonstrated through experimental work. Evaluation of operational data from existing plants has also indicated the definite presence of anaerobic stabilization at plants that include anaerobic zones for EBPR as part of their operation. By exploring the biochemical reactions taking place in EBPR process, particularly the involvement of the storage mechanisms for PHA, poly-P and glycogen storage, the potential mechanisms of the anaerobic stabilization of COD in EBPR systems was explored. The resultant balances pointed out the importance of glycogen metabolism in terms of conserving carbon and providing a sink for the reducing equivalents produced under aerobic conditions. This mechanism is different from those observed in anoxic-aerobic and conventional aerobic activated sludge systems, and appears to be at least partially responsible for the observed anaerobic stabilization of COD. 相似文献
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为了解决传统混合充氧机能耗高、水下安装维护难的问题,研制了新型文丘里混合充氧机,重点研究了电机转速对文丘里混合充氧机工作性能的影响。结果表明,在电机转速200~1 400 r/min条件下,文丘里混合充氧机的循环水量与电机转速呈线性关系;建立了基于气泡羽流模型的径向混合水流运动模型,并利用实测流速数据优化了水流的能量损失系数及夹带系数,成功模拟了不同电机转速条件下的径向水流速度分布;研究了不同电机转速条件下的有效混合半径,确定了文丘里混合充氧机的合适安装间距。电机转速400~1 200 r/min条件下,当电机转速逐渐增大时,水体复氧速率、氧的总传质系数和氧的传质效率均随之增大,混合充氧性能随之改善。 相似文献
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针对明渠调水工程中流量切换时,由于调控不当导致闸前水位突破水位上下限的问题,提出安全调控可行
域的概念及其划分原则,通过一维水动力模型耦合二分法建立明渠调水工程节制闸的安全调控模型,实现流量切
换时节制闸调控开度、安全水位和调控时间区间的计算,进而得到节制闸的安全调控可行域和调控方案,并以南
水北调中线工程陶岔渠首至淇河节制闸 4 个节制闸开展实例研究。研究过程中根据各节制闸流量变化情况,分
别设置 12 种工况进行计算,结果表明:经模型计算的调控方案调控后,闸前水位控制在安全水位区间内,划分的
安全水位区间-Ⅱ较水位区间-Ⅰ起到了降低水位变幅的作用,模型运算速度快,最长时间为 8.99?s。给出了柔性调
度方案,使得调度更为灵活,面向实际工程更实用、操作性强,为调水工程的调度决策提供了支撑。 相似文献
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长距离输水工程输水量大、闸门群和分水口群众多、控制要求高,在突发水污染事件下要求保障输水过程稳定、应急处置高效。研究了南水北调中线总干渠Ⅲ级水污染的应急处置水力调控方案,提出了Ⅲ级水污染的应急处置策略,确定了基于分水口水力特性的水力调控单元划分方法和应急处置水力调控方式。以京石段为例,提出了采用不同分水口群或等容积运行规则的3种应急调控方案,并利用建立的一维水动力水质耦合模型,模拟了不同应急调控方案下的水流运动和典型污染物的输移过程。研究表明,三种应急控制方案均能在不弃水、不显著影响上下游运行的条件下,通过利用渠道自身调蓄能力或发挥分水口的调控作用,实现应急调控目标。 相似文献
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You Zhen-jiangDepartment of Mechanics Zhejiang University Hangzhou ChinaZhou Zexuan Tan Soon Keat School of Civil Structural Engineering Nanyang Technological University Singapore 《水动力学研究与进展(B辑)》2003,15(1)
1 . INTRODUCTIONWaterhammerinhydraulicsisusedtodescribethenonlinearphenomenoninwhichpressuresurgesoccurfollowingasuddenchangeintheflowrateinapipesystem .Thechangeinflowvelocitymaybeinducedbyvalveoperation ,closureoropeningpumpstart uporshut down ,fluidinj… 相似文献
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Many river networks are controlled by sluices, especially in plain area. To prevent potential floods, maintain water level, and improve water environment in the inner river, the water transfer of river networks is needed and executed often in terms of optimized operation rules of sluices planned in advancing. To guarantee maintaining the optimized operation status, the provision of appropriate operating framework of sluices in river networks is necessary and presented in this study based on the knowledge-driven and data-driven mechanism. The general framework is formed by River Networks Mathematical Model (RNMM), Artificial Neural Networks (ANN) and Genetic Algorithms (GA), in which, ANN is used to build a rapid simulation of the flow variables in river networks, RNMM is used to train the ANN model, and GA method, whose fitness function is constructed by the ANN model, is used to optimize the operation rules of sluices. As a demonstration, the framework was applied to water transfer project of the tidal river networks locating in Pudong New Area of Shanghai in mainland China. Firstly, RNMM of Pudong was built and validated according to observed data during water transfer tests. Then, the Backward Propagation Neural Networks (BPNN) model was established as the fast simulation tool of flow variables of river networks through the numerical experiments with RNMM. The Generalized Genetic Algorithms (GGA) was recommended as optimization algorithm of sluices operation rules. Through comparing the optimization results with the RNMM simulation outputs under eight cases, it is verified that the framework can offer sub-optimal operation rules of sluices in river networks and present excellent speediness, robustness and flexibility. It is encouraged to be applied to more complicated, practical problems. 相似文献
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嘉陵江草街水电站尾水渠段由于乱石突出,水流紊乱,河床淤塞,导致运行尾水位偏高,水头损失增大,水轮机工作水头降低.针对上述问题,拟通过对渠道扩挖清淤,改善尾水渠流态,保证下泄畅通,降低尾水位,扩大水电站发电效益.建立了尾水渠段二维水流数学模型,模拟计算了多级流量下尾水渠清挖范围内水位、流场及流速分布情况,计算成果表明,扩... 相似文献
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为了实现滇池流域截污效果的最大化,基于前期建立的东岸排水管网SWMM模型,结合该区域1995-2016年间降雨资料,研究环湖截污干渠的错峰调蓄技术。根据雨水干渠液位高度执行不同控制模式:当水位低于6.76 m时执行典型污染物浓度阈值控制模式;当水位高于6.76 m时执行典型污染物阈值控制的同时执行液位-污染物通量控制模式。采用SS和TN作为干渠截流的典型污染物控制指标,其控制浓度阈值分别取12和5 mg/L。模拟重现期为0.5~1 a降雨时SS、TN浓度-负荷通量调蓄方案下干渠负荷收集情况,结果表明两种调蓄方案均能有效提高雨水干渠的负荷收集率,提高污水干渠出口浓度,降低雨水径流对污水厂的高水量和低浓度冲击负荷。随着重现期增大,干渠对污染物的高效和最大化收集效果越明显。但是TN调控下污染负荷收集效果优于SS,因此选择TN作为干渠截流的最优典型污染物控制指标。 相似文献
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水力式新型升船机关键技术研究 总被引:1,自引:0,他引:1
水力式升船机是我国具有自主知识产权的新型升船机。采用理论研究、物理模型试验、数学模型计算和现场试验与原型观测等研究手段,依托世界首座景洪水力式升船机的建设,针对水力式升船机的设计理论和方法、水力驱动同步技术及流量均衡和液面稳定技术、多重耦合作用下船厢倾斜机理与抗倾理论与技术、非恒定变速条件下船厢运行控制技术、高水头工业阀门防空化技术、微间隙机械同步系统制造安装技术等重大技术难题进行了全面系统研究,取得多项突破性研究成果,实现了70 m级水力式升船机平稳运行,为景洪升船机的建设和水力式新型升船机的推广应用奠定了坚实的基础。 相似文献
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Water resources planning and management at basin scale is such a large and complex problem that makes it essential to use
effective modeling tools in order to obtain an optimum plan for river basins development. In this paper, a methodology is
presented for optimized design and operation of the upstream Sirvan basin in Iran. The model proposed integrates MODSIM generalized
river basin network flow model, with the capability of simulating various characteristics and features of water resources
in a river basin, and Particle Swarm Optimization (PSO) algorithm. In the developed PSO-MODSIM model, the size of planned
dams and water transfer systems, as design variables, and the relative priorities for meeting reservoir target storages, as
operational variables, are varied and evolved using PSO algorithm. MODSIM is called to simulate the system performance and
to evaluate the fitness of each set of those design and operational variables with respect to the model’s objective function.
The PSO objective function is to maximize the total net benefit consisting of benefits due to supplying water to different
types of water uses and construction costs of dams and water transfer and/or pumping systems. Varying the design and operational
variables in MODSIM 8 is done using the MODSIM’s custom coding feature in VB.NET routine. The PSO-MODSIM model is used to
size the planed water storage and transfer components of a river basin system and to allocate water resources optimally over
time and space among competing demands, considering coordinated operation of the system components. The model results has
been analyzed for different scenarios of water transfer from Sirvan to neighboring basins. 相似文献
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恒定条件下,气垫式调压室室内气压与水位随机组运行工况变化而变化,该变化不仅取决于上库水位、机组出力等,而且取决于气垫式调压室室内气压设定值。若上库水位变幅较大,气压设定值将直接关系到气垫式调压室运行安全。为此,该文建立了设有气垫式调压室的引水发电系统恒定流数学模型,推导出了室内水位与气压的解析解,分析了上游水位、引用流量、初始设置水位、调压室顶部高程对室内气压与水位的影响,探讨了室内水位变幅与上库水位变幅之间的匹配关系,由此给出了室内水位/气压设定值选取范围,对电站设计和运行具有参考价值。 相似文献
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