水流交汇对过饱和总溶解气体生成及释放规律的影响研究

Confluence and interaction of flows downstream of high dam, such as entrainment of powerhouse flow by spillway release, and confluence of mainstream and tributary channels are common, which can impact the generation, dissipation and transportation of supersaturated total dissolved gas (TDG) considerably. By employing comprehensive field observation, laboratory experiments and numerical simulation, hydrodynamic-based study about the mechanics of the extra TDG generation through the entrainment of powerhouse flow will be explored. The interaction between the powerhouse flow and the spillway discharge, and also the interaction between the mainstream and tributary flows are to be searched thoroughly and the effects on TDG mass transfer rate will be addressed. The quantitative prediction model for supersaturated TDG affected by the interaction of confluences will also be developed, aiming to simulate the spatial-temporal distribution of supersaturated TDG. The project extends the research about supersaturated TDG from single-flow (spillway discharge) to double-flow(confluence). It is of great importance in improving the prediction of high-dam supersaturated TDG, promoting the research about mitigation measures of supersaturated TDG and developing environment-friendly hydropower projects.

在高坝泄水下游，水流交汇与相互作用(包括泄水与发电尾水的卷吸和汇合以及干支流交汇等)对过饱和总溶解气体（TDG）生成、释放以及输移扩散过程的影响作用显著。本研究将综合运用原型观测、室内实验及数值模拟等技术手段，从水动力学特性的研究入手，揭示泄水卷吸发电尾水增加过饱和TDG生成的机理，探求泄水与发电尾水汇合以及干支流交汇等水流间的相互作用对过饱和TDG传质系数的影响，建立水流交汇作用下过饱和TDG浓度的定量预测理论和方法，研究交汇水流影响下过饱和TDG时空分布变化规律。本项目的研究将以往对单股水流（泄水）过饱和TDG的研究拓展到交汇水流（泄水与发电尾水汇合以及干支流交汇），对于进一步提高高坝工程过饱和TDG研究和预测水平，促进过饱和TDG影响减缓措施的研究，建立环境友好型水利工程具有重要的理论和现实意义。

在高坝泄水下游，水流交汇对过饱和总溶解气体（TDG）生成、释放以及输移扩散过程以及鱼类回避空间的营造具有非常重要的意义。本研究综合运用原型观测、室内实验及数值模拟等技术手段，建立了综合考虑气体承压和滞留时间、水深等因素影响的高坝泄水过饱和TDG水动力学预测模型，揭示了水温、风速、二次流等因素对过饱和TDG释放系数的定量影响，研发了不同泄水建筑物联合运行及非恒定泄水条件下过饱和TDG输移释放预测模型，揭示了水流交汇过饱和TDG输移和释放规律，提出了利用交汇区为鱼类营造过饱和TDG回避空间的技术。本项目的研究对于进一步提高高坝工程过饱和TDG研究和预测水平，促进过饱和TDG影响减缓措施的研究，建立环境友好型水利工程具有重要的理论和现实意义。