泵闸工程闸下双底坎整流的水力特性

Study on hydraulic characteristics of double-sill rectification downstream a sluice-pump station

针对泵闸工程中出闸水流出现的不良流态,提出在其下游河道设置双底坎的整流措施,利用VOF法的RNG k-ε湍流模型,探索其整流效果和水力特性,并对计算结果进行了物理模型验证。结果表明:底坎通过迫使出闸水流沿坎横向运动和形成漩涡,对偏流、回流和斜向水跃具有显著改善作用;双底坎的设置能有效减小坎后水面波动,进一步降低回流区范围,提高流速均匀程度;流速不均匀系数随下游出口Fr增大而减小,随二坎的相对坎高h 2/b、相对间距d 2/b的增大先减小后增大;数学和物理模拟的水面线和流速分布吻合度较高,湍流模型计算结果可靠。

Aiming at the undesirable flow patterns in the discharging flow of a sluice-pump station,double sills were applied in the downstream for rectification.The rectification effects and the hydraulic characteristics were explored based on RNG k-εturbulence model and VOF method.The calculation results were verified by a physical model experiment.The results show that the sill forces the discharge flow to move laterally along the sill and form a vortex which can significantly improve the flow bias,backflow and oblique jump.The double sills can effectively reduce the wave motion,the recirculation zone,and improve the uniformity of velocity.The velocity non-uniformity coefficient decreases with the increase of the Fr number at the downstream outlets,and decreases first and then increases with the increase of the relative height h 2/b and relative spacing d 2/b of the second sill.By qualitatively and quantitatively comparing the mathematical and physical model results,it is found that the water surface curve and the velocity distribution are well consistent with each other,indicating that the numerical simulation of the turbulence model applied is reliable.