过渡阶梯大小对一体化消能工消能特性的影响研究

摘要

The integrated energy dissipater consisted of flaring gate pier,staircase spillway dams and stilling pool is widely used in modern high-head large unit width hydropower project.Based on Ahai Hydropower Station,the impacts of the connection of WES surface and staircase spillway dams on hydraulic characteristic of energy dissipater are studied.The gas-liquid two-phase flow VOF computing method complemented with 3-D RNG k-ε turbulence model are used to simulate four transition ladder schemes,which include 12 steps with size of 0.5 m ×0.375 m (hight ×width),6 steps with size of 1 m ×0.75 m,3 steps with size of 2 m × 1.5 m and 4 steps with size of 3 m × 2.25 m.The results show that:(a) with the increase of transition ladder size,the maximum turbulent kinetic energy k of dam face is gradually reduced,the maximum turbulent dissipation rate ε is gradually increased and the energy dissipation rate is also gradually increased;and (b) the distribution rules of k and ε in stilling basin are basically same in the bottom and middle of the front end of stilling basin.The transition ladder scheme with two 3 m × 2.25 m steps has best energy dissipation.%由“宽尾墩+阶梯溢流坝+消力池”组成的一体化消能工在现代高水头大单宽泄流量的水利水电工程建设中得到广泛的应用.基于阿海水电站,研究了WES曲面与阶梯溢流坝连接处的连接形式对该消能工水力特性的影响.采用水气两相流VOF计算方法辅以三维RNG k-ε湍流数值模型,对分别由12个0.5 m×0.375 m(高×宽)台阶、6个1 m ×0.75 m(高×宽)台阶、3个2m×1.5m(高×宽)台阶以及2个3 m×2.25 m(高×宽)台阶组成的过渡阶梯进行三维数值模拟.研究结果表明:随着过渡阶梯台阶尺寸的增大,溢流坝面最大湍流动能k逐渐减小,最大湍流耗散率ε逐渐增大,消能率也将逐渐增大;k及ε在消力池内分布规律基本一致,主要分布在消力池前端的底部和中部.由2个3 m×2.25 m(高×宽)台阶组成的过渡阶梯消能效果最好.