四大家鱼幼鱼响应模拟水轮机流道压力变化试验研究

大坝的建设阻隔了鱼类的洄游通道,鱼类通过水电站水轮机下行或误入水轮机流道有可能被流道内复杂的结构及水动力特性损伤,甚至致死。为优化水轮机流道结构及水动力特性,降低流道内鱼类的损伤概率,需明确鱼类对水轮机流道内水动力特性的响应关系,特别是河道内主要鱼种对反击式水轮机流道内压力突变的响应关系。本文以长江半洄游性鱼类四大家鱼幼鱼为研究对象,采用透明高压舱及真空泵组成的实验装置模拟轴流式水轮机流道压力变化过程对四种家鱼幼鱼的影响。实验得出,生活于河流中表层的鲢鱼和鳙鱼较生活于河流中底层青鱼和草鱼的对负压及压力梯度具有较强的敏感性；四种家鱼幼鱼均受损伤的低压阈值为20kPa；压力最低值及压力变化梯度是决定家鱼幼鱼是否受到损伤及损伤程度的关键因子。结果可以为我国长江流域上水电站水轮机的结构优化和生态运行提供技术支撑。

Effect of Sudden Pressure Change in Turbine Passages on Juveniles of the Four Major Chinese Carps

The construction of the dam blocks fish migration. The complex flow passage construction and the hydrodynamic characteristics in a turbine may cause the entrained fish damage or even death. In order to optimize the flow passage of hydraulic turbine and reduce the damage probability of the entrained fish, it is important to investigate the relationship between the hydrodynamic characteristics of turbine passage and fish adaptability, for example, the major fish species response to the pressure variation in reaction turbine passage. The four major Chinese carps as the research objects, the experiments of the fish response to pressure variation in turbine passage were done on the facility which compose of hyperbaric cabin and vacuum pump etc. The results suggest that bighead carp and silver carp are more sensitive than black carp and grass carp to negative pressure and pressure gradient, the minimum pressure value which is security to four major Chinese carps is 20kPa, the minimum pressure value and change gradient are key factors which hurt Chinese carps in turbine passage. This results improve the optimization of structure and ecological operation of turbine which are installed on Yangtze River