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为了更加全面分析混流式水轮机飞逸退出过程的水力特性,以水轮机的全流道为计算控制域,运用RNG k-湍流模型、动网格和滑移网格技术,对筒阀60和26 s两种动水关闭方式进行了三维非定常流动数值模拟,对比分析了两种动水关闭方式下阀体周边的压力、速度等流场的流态分布状况,以及筒阀附近包括蜗壳、导叶、转轮等在内的过流部件的流场特征。计算结果表明,与60 s动水关闭方式相比26s动水关闭方式明显缩短了飞逸时间,有利于操作的稳定性,可以更好地降低飞逸现象对水轮机组造成的破坏。同时,对于研究更为合理的筒阀运动方式、水轮机的水力设计与优化都具有一定的参考价值。
In order to fully analyze the hydraulic characteristics of the Francis turbine during the runaway process, the full runner of the turbine is used as the control domain. By using RNG k-turbulence model, moving grid and sliding grid technology, Two kinds of water shut-off methods were used to simulate three-dimensional unsteady flow. The flow distribution of pressure field, velocity and other flow fields around the valve body were compared and analyzed. Leaves, runners, etc. Flow components of the flow field characteristics. The results show that compared with the 60 s dynamic water shut-off, the 26 s shut-off mode significantly shortens the fly-off time and helps to stabilize the operation, which can further reduce the damage caused by runaway to the turbine. At the same time, it is of certain reference value for the research on the more reasonable cylinder valve movement mode and hydraulic design and optimization of hydraulic turbine.