阶梯凸起数量对一体化消能工水力特性的影响

Effect of number of raised ladder on the hydraulic characteristics of integrated energy dissipator

基于阿海水电站5孔溢流表孔,在掺气坎高度1m、角度10°的条件下,对Y型宽尾墩+阶梯溢流坝+消力池一体化消能工进行阶梯凸起数量分别为0,1,2,3的4种过渡阶梯进行水工模型试验,分别从水流流态、消力池水面线、近底流速、负压、时均压强以及消能率等多个水力特性进行研究.研究结果表明,近底流速随着可掺气空腔体积的增大而减小,随着阶梯凸起数量的减少而增大,在二者相互作用下,各方案流速在消力池末端达到最小,其中方案2流速最小,为22.23m/s;由于可掺气空腔体积和凸起型阶梯的数量的共同影响,方案2的负压最小,达-33.66kPa;方案1,2,3,4的消能率依次为59.56%,61.06%,60.37%,59.99%.方案2的消能率最高.

The transitional ladder has a certain influence on the integrated energy dissipation mode of flaring gate piers,stepped spillways and stilling basins,and raised ladder is particularly important for this effect.In order to explore this effect,a numerical simulation on the 5-hole transitional ladder design for the spillway of Ahai hydropower station was presented.With an aerator height of 1m at an angle of 10°,for the flaring gate piers combined with stepped spillway and stilling basin,the hydraulic model test was carried out for the four kinds of transition steps with the number of raised ladder 0,1,2 and 3,respectively.Various hydraulic characteristics such as the surface line of the stilling pool,the near-bottom flow velocity,the negative pressure,the time-averaged pressure and the energy dissipation rate were studied.The results show near-bottom flow velocity decreases with the increase of the volume of the aerated cavity,and increases with the decrease of the number of stepped protrusions.Under the intera-ction of the above two conditions,the flow velocity of each solution reaches the minimum at the end of the stilling pool,the flow velocity of model 2 is the smallest,reaching 22.23 m/s.Owing to the collective effect between the volume of the aerated cavity with the number of raised ladder,the negative pressure of model 2 is the smallest,reaching-33.66 kPa.The energy dissipation rates of models 1,2,3 and 4 are in turn 59.56%,61.06%,60.37%and 59.99%,respectively.The energy dissipation rate of model 2 is the highest.