大型泵站前池扩散角对进水流态的影响

The influence of forebay diffusion angle on inflow pattern in large pumping station

为研究前池扩散角对大型低扬程泵站进水流态的影响,依托某大型低扬程泵站基本设计参数,基于Navier-Stokes方程和RNGk-ε湍流模型对不同前池扩散角和不同开机组合工况下的泵站进水流态进行三维湍流流动数值模拟,分析不同前池扩散角下的进水流态、流速分布均匀度和横向流速的变化情况,并通过物理模型试验进行验证。结果表明:大型泵站机组不对称运行时,前池内存在漩涡区,进水流道进口前存在较大的横向流速;随着前池扩散角减小,机组不对称运行时,前池内漩涡区范围减小,水流偏流情况改善,前池内流态逐渐变好,进水流道进口前横向流速大幅减小,流道进口处流速分布均匀度提高,进水流道的进水条件改善;不同前池扩散角下的进水流态数值模拟结果与模型试验结果一致。研究成果对大型低扬程泵站的前池设计有一定的参考价值。

Based on the basic design parameters of a large low-head pumping station and the Navier-Stokes equations as well as RNG k-εturbulence models,three-dimensional turbulent flow numerical simulations are carried out to study the influence of forebay diffusion angle on the inlet flow pattern of the large low-head pumping station.Under different forebay diffusion angles and different start-up combination conditions,the changes of inlet flow regime,velocity distribution uniformity,and and lateral velocity are analyzed and verified by physical model tests.The research results indicate that the vortex zone is existed in the forebay,and a large transverse flow velocity is existed in front of the inlet channel during asymmetric operation of large pumping station.As the diffusion angle of the forebay decreases,the range of vortice decreases and the flow deviation situation improves during asymmetric operation of the pump.The flow pattern in the forebay gradually improves,and the transverse velocity in front of the inlet channel decreases significantly,the velocity distribution uniformity at the inlet channel increases,and the inlet condition of the inlet channel improves.The numerical simulation results of the inlet flow regime under different diffusion angles in the forebay are consistent with the model test results.The research results have a certain reference value for the design of the forebay of large low-lift pumping stations.