阶梯溢流坝与跌水建筑物复氧能力预测研究  

Prediction of re-aeration capability of flows over stepped spillways and hydraulic drop structures

作　　者：周新民 曾映雪[2] 程香菊[2] 

机构地区：[1]广州市河涌管理处,广州510640 [2]华南理工大学土木与交通学院,广州510641

出　　处：《水力发电学报》2014年第3期195-202,共8页Journal of Hydroelectric Engineering

基　　金：国家自然科学基金项目(50979118);中央高校基本科研业务费专项资金资助

摘　　要：溶解氧含量对于维持河流,特别是城市河流的生态环境起到关键作用。河流中修建的泄水建筑物不仅具有蓄水功能,而且在泄水过程中,可使水流湍动卷吸大量的空气进入水体,从而使溶解氧含量增加。为了对不同形状的泄水建筑物复氧能力进行预测,本文选择阶梯溢流坝和跌水型泄水建筑物作为典型的河道型泄水建筑物。在室内模型试验中,通过改变阶梯型溢流坝面上阶梯的高度(或宽度)和流量,测定了34种工况条件下的坝上、下游溶解氧浓度和水温,观测了掺气发生起始点的位置。对阶梯溢流坝面水流的复氧能力进行分析,建立了在相同坝高条件下阶梯溢流坝复氧效率与单宽流量、阶梯高度以及溢流坝底坡的定量关系式;通过收集整理跌水建筑物原型观测32组数据,建立了跌水建筑物复氧效率与跌水流量、跌水高度以及尾水深的定量关系式。这两个定量关系式的建立,可快速计算出阶梯溢流坝和跌水建筑物的复氧效率,给环保以及水利工作者优化设计低矮型泄水建筑物提供了理论依据。Content of dissolved oxygen is a key factor in maintenance of ecological environment for rivers, especially for the urban rivers. Spillway dams constructed on rivers not just have function of water storage, but cause a certain amount of air to be entrained into the water through flow turbulences in the discharging process so that the dissolved oxygen content of released flow is significantly increased. To predict flow re-aeration capability of different spillway shapes, this study focuses on two typical types of dams, i.e. lower stepped spillway and dropping hydraulic structure. For stepped spillways, laboratory experiment was conducted to test 34 cases of different combinations of the step height （or width） and flow rate. In each case, dissolved oxygen concentration and water temperature were measured at the dam＇s crest and toe and location of air entrainment inception was observed. From the measurements, a quantitative formula was established for re-aeration coefficients versus discharge per unit width, step height, and spillway slope. For dropping hydraulic structures, totally 32 sets of field measurement data were collected, and by using these data a quantitative formula of re-aeration coefficients versus dropping discharge, dropping height and depth of tail water, was also derived. The two formulas provide quick evaluation of re-aeration capability and the present work would lay a theoretical basis for lower spillway dams design optimized for environmental protection.

关 键 词：环境水力学 复氧能力 预测 阶梯建筑物 跌水建筑物 

分 类 号：TV135.2[水利工程—水力学及河流动力学]