混流式水轮机转轮诱发鱼类损伤的量化评估机制及抑制技术研究

Francis turbine in hydraulic engineering can cause serious damage to the fish in watershed during the operation. In order to alleviate the impact of hydraulic engineering on the ecological environment of fish in watershed, the following researches are planned to be carried out in this project. Firstly, based on the biological research achievement of salmon species damage and combined with the simulation method of internal flow of Francis runner, the analysis process of fish casualty rate caused by different damage mechanisms was established. Then, on the premise of revealing the time sequence law of various damage mechanism effects, fish casualty assessment mechanism of Francis runner is established by integrating various analysis processes. Secondary, bases on the membership degree theory, the key geometric parameters of Francis runner, which significantly affect the fish casualty rate and hydraulic performance, are identified. And the response relationship between the key geometric parameters and the fish casualty rate and hydraulic performance of Francis runner is established. Thirdly, after taking the fish casualty rate and the hydraulic performance of runner as objective functions and introducing the immune genetic algorithm and the response relationship established in the above research, the optimization system of Francis runner that considering the fish casualty rate and hydraulic performance is constructed. Thus, the fish casualty rate caused by Francis runner can be restrained in the design stage.

混流式水轮机在运转过程中会对流域内的鱼类群体造成严重伤害，为了缓解水利工程对流域内鱼类生态环境的影响，本项目拟开展以下研究：（1）以鲑鱼类鱼种损伤的生物学研究成果为基础，结合混流式转轮内部流场的解析方法，建立不同损伤机理作用下的鱼类通过伤亡率分析流程，然后在揭示各类损伤机理作用的时序规律前提下，综合各分析流程形成混流式转轮的鱼类通过伤亡率评估机制；（2）以混流式转轮的几何参数为对象，基于隶属度理论甄别其中显著影响鱼类通过伤亡率和水力性能的关键几何参数，并构建上述关键几何参数与转轮的鱼类通过伤亡率及水力性能间的响应关系；（3）以转轮的鱼类通过伤亡率及水力性能作为目标函数，引入免疫遗传算法并集成转轮关键几何参数与目标函数间的响应关系，最终形成兼顾鱼类伤亡率和水力性能的混流式转轮优化系统，从而在混流式转轮的设计阶段抑制其诱发的鱼类伤亡。

混流式水轮机是水轮机的主要机型之一，在国内的各大流域中均有应用。混流式水轮机在运转过程中，不可避免的会对流域内的鱼类群体形成严重伤害。为了缓解混流式水轮机对流域内鱼类及生态环境的影响，本项目对鱼类通过伤亡率的定量评估机制、转轮的鱼类友好性优化设计以及鱼类过机的动力学状态模拟开展了研究。主要研究成果如下：.(1) 建立了混流式转轮内压力和剪切应力造成鱼类损伤的概率计算方法，明确了撞击损伤和高压强梯度损伤是鱼类通过混流式转轮时的主要致损因素，阐明了转轮内易发生压力损伤和剪切应力损伤的位置。.(2) 项目中提出了减少叶片数、调整叶片各流面上安放角分布的鱼类友好型混流式转轮优化方法，并采用该方法对某中高水头段混流式转轮进行了鱼类友好型优化。优化结果表明，减少叶片数可显著降低混流式转轮诱导的鱼类撞击伤亡率和鱼类低压压强伤亡率，但混流式水轮机的效率在小流量工况下也有所降低。.(3) 基于IB-LBM理论，本项目建立了鱼类通过水轮机的运动状态模拟方法，获得了鱼类通过水轮机时的运动轨迹、表面压力和压强梯度的变化情况。同时还揭示了鱼类在通过水轮机时的姿态变化，为鱼类过机时的动力学状态研究提供了方法论。.(4) 基于IB-LBM方法研究了鱼类以不同初始位置进入贯流式水轮机时的过机轨迹及伤亡率变化情况，阐述了鱼群进入水轮机时的各条鱼受损伤概率的区别及造成损伤差异的机理。. 本项目的研究成果为混流式水轮机的鱼类友好性能定量评估提供依据，同时也为鱼类通过水轮机时的动力学状态研究奠定了基础。