X型和Y型宽尾墩水力特性对比研究

Comparison on hydraulic characteristics of X-shape and Y-shape flaring gate piers

为了探求X型宽尾墩与常规Y型宽尾墩水力特性的差别,采用RNGk-ε双方程紊流模型对两种型式的宽尾墩的三维流场特性进行数值计算,模拟结果与试验数据吻合良好,说明模型选用及网格划分合理。比较分析两种墩型水流流动特征、宽尾墩体和下游溢流坝面的压力分布以及闸室出口流速分布发现X型宽尾墩不但具有常规Y型宽尾墩分散水流、增加掺气量和提高消能效率等优点,而且在小流量时可增大泄流能力,特别是在与台阶式坝面联合运行时,还可改善坝面压力分布;其缺点是X型宽尾墩出口处局部出现负压,设计时应给予注意。

In order to investigate the differences of hydraulic characteristics between X-shape flaring gate piers （FGP） and Y-shape flaring gate piers, the RNG k-ε turbulent model was applied to numerically simulate the 3D flows in stepped spillways with flaring gate piers. The good agreement of data measured in model with those computed verifies the validity of the model and rationality of mesh dividing. It is found that the X-shape flaring gate piers not only can disperse the overflow, entrain air and improve the energy dissipation efficiency as Y-shape flaring gate piers, but also have larger discharge capacity than Y -shape flaring gate piers, especially in lower reservoir water level. Moreover, the surface pressure distribution of the stepped spillways with X-shape flaring gate piers is closer to uniform. It must be pointed out that local negative pressure exists at the floor of the notched surface of X-shape flaring gate piers, which may lead to cavitation damage.