In order to avoid cavitation damage on surfaces of the first few steps of a stairway spillway, an aerated hurdle was added to the design of stairway spillway to form a pre-mixed culvert spillway. The transition step shape with improved hydraulic characteristics was sought in terms of cavity length, water line, negative pressure, time-averaged pressure on stilling bottom, energy dissipation and so on by changing reservoir flow through experiments on a series of hydraulic models. In these experiments, the first step in the transition step was fell by 0, 5?, 10? and 15?, and the pre-aeration angle has 8?, 10? two values, the joint energy dissipators with Y-shaped flaring gate piers, stepped spillway and stilling pool were built based on eight combinations of these parameters respectively. The results show that the aerated cavity increases with increasing pre-aerator and first stage angle, the higher the water jet, the larger the space separating from the dam surface and the longer the cavity length. The length of cavity in working condition 2 is longer than in working condition 1; the absolute value of the maximum negative pressure decreases with increasing aerator and first step slope. The pressure and water line are not changed much, and the energy dissipation rate increases. Thus, the fifth case with 10? pre-aerator angle and 0? first stage step slope is the best combination in eight experimental combinations.
ZHANG Qin,YANG Ju-Rui-*,TANG Jian-Qing et al. Effect of combination of aerated hurdle and first stage step on stepped spillway surface[J]. Journal of Drainage and Irrigation Machinery Engin, 2019, 37(3): 216-223.
WANG Qiang, YANG Jurui, WU Zhenzhong, et al. Impact of transition ladder with different number of steps on dam surface pressure and energy dissipation of stepped spillway[J]. Journal of hydroelectric engineering, 2016,35(5):84-93.(in Chinese)
WANG Qiang, YANG Jurui, JIANG Yu, et al. The influence of energy dissipation characteristics of transition steps combined by different size of steps of flaring gate pier + step overflow dam + stilling basin[J]. Journal of Tongren University, 2017,19(9):40-47.(in Chinese)
ZHANG Qin, YANG Jurui. Study on the effect of first stage angle on the aeration of stepped spillway under different pre-aerator angles[J]. Chinese journal of hydrodynamics, 2018,33(2):245-253.(in Chinese)
ZHANG Qin, YANG Jurui, YE Xiaosheng, et al. Impact of the first step table-board angle on hydraulic characteristics of combined dissipater[J]. Journal of drainage and irrigation machinery engineering, 2018,36(4):313-319.(in Chinese)
ZHANG Luo, HOU Xiaoxia, YANG Jurui. Study on impact of flaring gate pier shape on hydraulic characteristics of flow in sidewall region[J]. Journal of hydroelectric engineering, 2015,34(1):85-92.(in Chinese)