摘要
为寻找尾水管压力脉动与转轮出口流态的关系,揭示影响尾水管内不稳定流动的主要因素,采用了SIMPLEC方法和RNGk-ε模型,计算了混流式转轮在各种稳定工况下的流场,重点分析典型工况下的出口流态;针对这些典型工况进行不稳定流动计算。分析表明,尾水管内部涡带的形成不仅与转轮出口圆周速度有关,而且转轮出口有无回流和回流区的大小与涡带形成和涡带特征密切相关。
The relationship between draft tube surges and the runner outlet flow patterns were investigated to identify the main factors causing the surges. The steady flow field in the runner was calculated numerically for different operating conditions using the SIMPLEC method and the RNG kε turbulence model. The unsteady outlet fields were then simulated for the different outlet flow patterns. The analyses show that the draft tube vortex rope is not only related to the tangential velocity distribution, but also to the axial velocity profile at the runner outlet. The axial velocity gradient is large at the interface between the reverse flow and the normal flow when the flow reverses at the center of the outlet, so a vortex tends to form if the tangential velocity is also large at the runner outlet.
出处
《清华大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2002年第12期1670-1673,共4页
Journal of Tsinghua University(Science and Technology)
基金
三峡工程基金和清华大学"九八五"研究基金资助
