含沙量对过饱和总溶解气体释放过程影响分析.docVIP

 n 含沙量对过饱和总溶解气体释放过程影响 分析# 冯镜洁1，李然1，唐春燕2，雍晓东1** 5 10 15 20 25 30 35 （1. 四川大学水力学与山区河流开发保护国家重点实验室，成都 610065； 2. 广西水利电力勘测设计研究院，南宁 530023） 摘要：高坝泄水产生的过饱和总溶解气体（TDG）一般不会快速释放，而是随流输移至下游 相当长的距离，由此可能导致鱼类患气泡病甚至死亡。由于高坝泄水常为高含沙水流，因此 含沙水体过饱和 TDG 释放规律的研究具有重要的理论和现实意义。为探讨泥沙含量以及紊 动强度等特性对过饱和 TDG 释放过程的影响，本文设计了静置水柱、搅拌诱发紊动以及明 渠水流 3 种实验条件，通过对不同含沙量工况下过饱和 TDG 释放过程的观测研究，分别计 算得到各工况下的释放系数。结果表明，泥沙含量和紊动强度均对过饱和 TDG 的释放起着 促进作用，而且随着含沙量和紊动强度的增大，释放系数逐渐增大。本研究对于过饱和 TDG 数值模拟研究中释放系数的取值具有指导意义，同时也可为过饱和 TDG 影响的减缓措施研 究提供基础数据和参考依据。 关键词：总溶解气体；过饱和；含沙量；紊动强度；释放 中图分类号：TV131.2 Effect of sediment on the releasing process of supersaturated total dissolved gas FENG Jingjie1, LI Ran1, TANG Chunyan2, Yong Xiaodong1 (1. State key laboratory of hydraulics and mountain river engineering, Sichuan University, Chengdu 610065; 2. Guangxi water and power design institute, Nanning 530023) Abstract: Supersaturated total dissolved gas (TDG), generated by high-dam discharges, generally will not dissipate rapidly in downstream rivers. During its transportation over long distances, supersaturated TDG may lead to gas bubble disease or even heightened fish mortality. Because the sediment concentration is always high in spill flow in China, studying the releasing law of supersaturated TDG in sandy water is of great theoretical and practical value. In the experiment described in this paper, we designed three kinds of experimental conditions, including a static water column, stir-induced turbulent water and open channel flow. For each experimental condition, the TDG release processes were monitored both in clean water and sandy water. The release coefficients were calculated and compared under different sedimentation levels. The results indicate that both sediment and turbulence intensity can increase the release speed of TDG. The higher the sediment concentration level and turbulence intensity are, the bigger the release coefficients are. The study can provide important guidance for determining release coefficients in a TDG simulatio