大坝泄流水体溶解气体饱和度预测方法初探

Prediction method of dissolved gas concentration downstream of high dams

大型水电工程对水生态环境的影响一直是国内外广泛关注的问题。当水库闸坝泄流时,可能会使下游水体溶解气体浓度超饱和,导致鱼类等水生动物患气泡病,威胁它们的生存和繁殖。如何准确而快速地计算或预测高坝泄洪水体溶解气体的浓度迫在眉睫。本文根据泄水建筑物实测数据,计算出泄流水体气体传质速率,并发现在水力条件一定时,闸坝泄水建筑物气体传质速率不变的特性,在此基础上,结合有效饱和浓度、有效水深以及上游溶解气体饱和度等参数,建立了对闸坝下游水体溶解气体饱和度进行预测的方法。预测结果表明,该方法具有计算简便且应用广泛的特点。

The eco-environmental effects of large-scale hydropower project attract a great concern for long.Dissolved gas could be supersaturated downstream of a spillway and may cause fish gas bubble disease and eventually a certain mortality.It is very important to search for an accurate and quick method to predict the dissolved gas concentration.In this paper,the dissolved gas transfer efficiencies are calculated by using the measured data of a spillway.The results show that under a given flow condition the transfer efficiency is a constant value independent of the upstream concentration or the tail water depth.By this observation,this paper develops a method to predict the dissolved gas concentration downstream of a spillway with the given conditions of transfer efficiency,upstream dissolved gas concentration and tail water depth.This method is simple and easy to apply to a practical project.