修圆角形过渡阶梯对阶梯溢流坝消能特性的影响

Influence of rounded transition step on energy dissipation characteristics of stepped spillway

本文以阿海水电站的阶梯溢流坝为原型,应用水气两相流VOF计算方法以及三维RNG k-ε紊流模型,采用PISO耦合的算法计算速度、压力,利用几何重建格式迭代求解非恒定流,对过渡阶梯段的圆角半径R为0.188m、0.219m、0.250m时的修圆角形过渡阶梯进行数值模拟。主要针对阶梯溢流坝的压力场、紊动动能等水力特性进行研究,分析修圆角形阶梯的圆角半径对阶梯溢流坝面消能的规律。模拟结果表明,修圆角形阶梯的半径越大,在阶梯溢流坝面产生的时均压强越小,紊动动能越大,消能效果越好。圆角半径为0.250m时的修圆角形过渡阶梯在阶梯溢流坝面上的时均压强最小,为112.985kPa,紊动动能最大,为9.090m ^(2)/s ^(2)。

Taking the stepped overflow dam of Ahai Hydropower Station as the prototype,the water-gas two-phase flow VOF calculation method and the three-dimensional RNG k-εturbulence model are used.The PISO coupled algorithm is used to compute velocity and pressure,and the geometric reconstruction format is iteratively solved for the non-constant flow.Numerical simulations are conducted for rounded transition steps with circular corner radii of 0.188m,0.219m,and 0.250m.The focus was on studying hydraulic characteristics such as pressure field and turbulent kinetic energy of the stepped spillway,analyzing the effect of rounded corner radii on energy dissipation on the spillway surface.The simulation results indicate that larger rounded corner radii on the transition steps result in lower average pressure and higher turbulent kinetic energy on the spillway surface,indicating better energy dissipation.The rounded transition step with a radius of 0.250m has the smallest time-averaged pressure on the stepped spillway surface,which is 112.985kPa,and the turbulent kinetic energy is the largest,which is 9.090m ^(2)/s ^(2).