Hydraulic experiments on spillway weir profiles

Spillway weirs are the system for regulating the flow in open channel flow passages. Weirs are commonly used to alter the flow of rivers to prevent floods, measure discharge and also in nuclear reactors for uniform cooling purposes. This paper describes the hydraulic experiments conducted for finding the air entrainment on water under laminar flow conditions in open channel flow passage with various profiles of spillway at flow rates in the range of 100–650?lpm. The concept of the spillway system allows stabilisation of the free level of water and avoids variation in the free level of water along the flow passage as a function of flow rate. The main problem in the spillway is the profiling of weir crest. The criteria that need to be satisfied are: (i) there should be no flow separation from the crest and (ii) there should be a uniform circumferential flow to avoid flow asymmetry in the passage. Separation of flow leads to large impact velocity of the falling water, which would lead to large-scale entrainment of air. When flow adheres to the weir crest and upstream, the impact velocity of water with the free surface would be less and hence entrainment would also be less.     

牛栏江引水工程盘龙江入口段瀑布堰体设计

以牛栏江引水工程盘龙江入口段防洪工程为例,介绍了该工程瀑布堰体的设计方案,着重对瀑布堰体的稳定性、应力及沉降变形进行了计算分析,计算结果表明:南段直坎段和北段三跌坎段瀑布在各荷载组合工况下,均能满足抗滑移、抗倾覆稳定性要求。     

钢板桩围堰在潮汐河流中的设计和施工

针对东莞市某输水工程位于潮汐河流的情况,采用了钢板桩围堰方案施工,文中对钢板围堰的设计、施工进行了分析,提出了围堰施工中应注意的事项,并比较了水中围堰与土中基坑设计的不同之处,为其他类似工程提供参考、借鉴。     

施工期厂房尾水薄壁堰三维非线性有限元分析

通过对薄壁堰-基岩-堆石体-河水（水压力）-门机运行荷载联合作用的三维有限元分析,进一步了解某水电站施工期厂房尾水薄壁堰混凝土结构的位移、应力分布,堆石体位移、应力分布情况,以期为施工期门机浇筑设计方案及薄壁堰加固处理方案积累经验。     

锡槽中石墨挡坎氧化机理探讨

石墨挡坎氧化是指溶解在锡液中的氧化亚锡（SnO）在一定浓度、温度和一定锡液流冲击强度3个条件共同作用下,与石墨挡坎中的碳（C）成分反应产生二氧化碳（CO2）后逸出。该文分析了锡槽中石墨挡坎氧化的机理,提出了处理石墨挡坎氧化的方法及其预防措施。     

Experimental studies on air entrainment and oxygen content downstream of sharp-crested weirs

The concentration of dissolved oxygen (DO) is an important indicator of water quality because aquatic life survives on the DO in water. A free overfall jet from a weir plunging into downstream water causes entrainment of air bubbles if the free overfall jet velocity exceeds a certain critical value and hence aeration occurs. This paper investigates the free overfall jets from sharp‐crested weirs and their effect on air entrainment and aeration efficiency. The results indicate that the air entrainment and aeration efficiency of triangular sharp‐crested weirs are significantly better than those for the other sharp‐crested weir types. Therefore, the triangular sharp‐crested weirs can be used as highly effective aerators in streams, rivers, constructed channels, fish hatcheries, water treatment plants, etc. Regression equations were obtained for the triangular sharp‐crested weirs relating air entrainment rate and aeration efficiency to drop height, discharge and angle in the triangular sharp‐crested weir. There was good agreement between the measured values and the values computed from the predictive equations.     

天兴洲长江大桥北汊桥钢吊箱围堰设计与施工

通过对武汉天兴洲长江大桥北汊主桥水中墩承台施工,综合介绍了深水基础钢吊箱围堰的设计内容,详细地阐述了钢吊箱围堰的施工工艺流程和施工方法,可供同类工程参考借鉴。     

污水截流井设计计算方法探讨

结合《合流制系统污水截流井设计规程》（CECS 91：97）中的计算方法，通过某一算例，分析比较了在雨天实际截流工况下，堰式、槽式、槽堰结合式三种截流井的实际截流量相对于设计截流量的增加倍数，并提出了减小该增加倍数的相关措施。同时，针对堰式污水截流井提出了计算堰高的新思路，并与原设计方法进行了比较。     

空气出水堰的气压控制改造

针对南方某污水处理厂空气出水堰在运行中出现的跑泥、出水流量不稳定、加压过量等问题,进行了气压控制改造,实现了双系统控制运行,增设了PLC故障报警、进气阀故障报警、过压故障报警、虹吸报警,使操作人员能迅速发现故障,并通过简单操作即能恢复空气出水堰的正常运行,大大提高了空气出水堰运行的稳定性和安全性.     

智慧截流井自动化控制技术设计及应用

截留井是城市排水系统广泛采用的一种工程技术,但传统截留井存在难以控制污水截流量、外部河(海)水倒灌、溢流污染物拦截效果差、控制及管理水平低等难题,智慧截流井采用物联感知、自动控制以及云服务技术实现智能化排水控制,是一种新型排水管网智能化监测与处置技术,值得应用推广。本文主要介绍基于压式堰门自动化控制系统的智慧截流井的系统功能、结构和主要技术设计,并介绍了设备应用模式和效果。     

宁德特大桥承台钢板桩围堰设计与施工

结合宁德特大桥海湾区承台施工,以58号墩为例,对承台钢板桩围堰的设计与施工进行了研究,详细介绍了钢板桩围堰设计及施工工艺,总结了钢板桩围堰在海工领域内施工应注意的主要问题,从而为同类桥梁施工积累了经验。     

Aeration Performance of Triangular-Notch Weirs

Hydraulic structures have an impact on the concentration of dissolved oxygen in a river system, even though the water is in contact with the structure for only a short period of time. The same oxygen transfer that would normally occur over several kilometres in a river can occur at a single hydraulic structure, because the flow over a structure is typically highly turbulent, resulting in increased interfacial renewal. Plunging overfall jets from weirs are a good example of this fact, and the aeration properties of such structures have been studied widely in the laboratory and field over a number of years. This technical note (a) describes triangular-notch weirs having a different weir angle α and how they affect aeration performance, and (b) demonstrates that aeration efficiency decreases with increasing weir angle.     

Three Examples of the Use of Physical River Channel Models by the National Rivers Authority,Yorkshire Region†

In recent years the Yorkshire Region of the National Rivers Authority has employed the technique of physical modelling to assist in the hydraulic design of urban flood-alleviation schemes. The paper describes three examples of their use. On the River Worth at Keighley the introduction of a weir, to reduce siltation beneath a bridge, was modelled. The confluence of Batley Beck and Howley Beck in Dewsbury is located at the entrance of a culvert. A model was constructed and streamlining was introduced to improve self-cleansing and reduce head-losses. On the River Calder at Wakefield, two bridges and a weir form a complex hydraulic situation. The results of a physical model study were used to aid the calibration of a mathematical model of a much larger area. The paper reviews these model studies, indicating the costs and the likely savings resulting from reduced siltation. The paper concludes that physical modelling can provide a cost-beneficial aide to river-engineering design.     

柔性滗水器的设计

目前国内普遍采用推杆旋转式滗水器,它的缺点是动力消耗大,推杆机械部件易出故障,滗水深度局限性较大.为此,笔者设计了新型柔性滗水器,重点解决了推杆滗水器现有技术的不足,达到了降低能耗、减少机械故障、延长使用寿命的目的.在滗水深度加大后,其驱动机构仍运行可靠.笔者重点介绍了该滗水器的驱动机构、保护装置以及堰槽结构.     

浮动式滗水器的设计和运行

介绍了采用自动橡胶球阀的浮动式滗水器设计原理和设计要点,并详述了完全国产化生产的大型浮动式滗水器在实际运行中的性能。研究表明,浮动式滗水器结构简单可靠、运行稳定、滗水深度大、适用范围广,其堰口负荷随着滗水的进行而逐渐减小,与SBR工艺匹配较好,既保证了出水水质,又具有较大的滗水能力。     

钢吊箱围堰的结构设计与施工

就深水高桩承台施工用钢吊箱围堰的结构设计与施工方法进行了论述,介绍了相应的施工特点,并通过对钢吊箱施工过程中结构的分析,揭示了施工过程中钢吊箱整体结构的受力特点,为今后类似工程的施工提供参考借鉴。     

某大型瀑布设计方案的选择研究

根据某工程的实际情况,提出四叠瀑和滑瀑两种瀑布方案,通过两种方案的瀑布构造、堰上水头、设计单宽流量和循环水泵选型的比较,得出了滑瀑方案更合适、能耗更小的结论。     

An experimental investigation of aeration performance in stepped spillways

Dissolved oxygen content is a prime indicator of water quality. The oxygen transfer across the air–water interface at a hydraulic structure, such as a weir or spillway, occurs by self‐aeration along the chute and by flow aeration in the hydraulic jump at the downstream end of the structure. Despite increased research activities in the field of stepped spillways, the aeration efficiency of stepped spillways is not yet known. This paper investigates the aeration efficiency of stepped spillways, in particular the effects of varying chute angle and step height. Empirical correlations predicting length of the nonaerated flow region and aeration efficiency were developed. The results indicate that stepped spillways are effective for oxygen transfer.     

Refurbishment of Control Structures on the River Avon at Strensham Lock

Three control structures at Strensham lock maintain the water level in the upstream pound of the River Avon for navigation, ecology and angling purposes. The National Rivers Authority † , which currently owns the structures, is responsible for their maintenance and for the operation of the vertical-lift sluice gates which are opened to control flooding. Construction work has recently been completed to secure the structures, which were in a poor state of repair and in danger of collapsing. The two sluice structures were completely rebuilt and the weir was modified.
The paper describes the planning, design and construction of the works, which are located within a 'site of special scientific interest'.