水泵水轮机叶道涡的串级及耗散特性分析

采用大涡模拟方法，对某水泵水轮机模型额定工况进行了全流道三维非定常湍流涡结构的串级特性分析，得到了涡结构在叶道中的串级分布特性，捕捉到了叶道涡的时空演化，探寻了不同尺度涡的存活率及串级形成的能量耗散通道。结果表明：即便在额定水轮机工况运行时，由于存在微小进口冲角，在叶片背面靠近上冠的区域形成的小量脱流，也将会演化形成叶道涡。叶道中“大尺度”涡的存活率相对较低，而“小尺度”涡的存活率则很高，相邻尺度涡量增大倍数在1.2 ~ 1.6之间。在叶道的一定区域内，叶道涡在串级过程中会逐步汇聚，相互干扰，涡湍黏性随之快速增加，导致湍动能沿叶道剧增，形成能量耗散的通道。

Vortex cascade and dissipation features of turbulent flow in hydro-turbine blade passage

This paper presents a large eddy simulation (LES) study of turbulent flow structures in a hydro-turbine operating in the rated condition, including the details of the well captured structures and an analysis on the features of vortex cascade and turbulent energy dissipation in blade passages. And survival rates of vortices in different scales and the corresponding energy dissipation are examined. Results show that the survival rates vary significantly over a blade passage and the volume ratio of vortices in two adjacent scales is about 1.2-1.6. The large scale structures in a blade passage feature low survival rates, while the small scale structures have quite high survival rates and dominate along the flow in the passage. Along the flow, turbulent kinetic energy and eddy viscosity are increasing rapidly and the small scale structures keep growing, implying how an energy dissipation channel is formed in the blade passage.