某水库阶梯溢洪道水力特性研究

Study on Hydraulic Characteristics of the Stepped Spillway of a Reservoir

采用标准k-ε双方程紊流模型,结合VOF法,对某水库阶梯溢洪道的水面线、流速、底板压强等水力特性进行了数值模拟,部分计算结果与1∶30比尺水工模型试验的结果进行了对比验证。结果表明:单宽流量较大时阶梯段水流为滑移水流流态,阶梯段水面较稳定;消力池内为淹没水跃,水面波动剧烈。台阶水平面外缘的压强明显大于内侧,各个台阶的压强分布规律一致,阶梯加消力池联合消能的效果显著,可供类似工程参考。相关水力参数的数值计算值和试验结果吻合良好,三维紊流数值计算可以获得流场的详细信息,表明采用上述紊流模型来计算阶梯溢洪道的流场是可行的。

The hydraulic characteristics of a stepped spillway, such as the water surface profile, velocity and bottom pressure, were carried out by means of the model of standard k-ε double-equations turbulence model combined with the volume of the fluid （VOF） model. Partial simulation results were compared and analyzed with the resuhs from the hydraulic model on a scale of 1 ： 30 conducted experimentally. The flow in steps is slip flow while unit width discharge is large. And the water surface profile on stepped section is stable, however, the submerged hydraulic jump presents in the stilling basin and the water fluctuates. The outer edge pressure in horizontal plane on the step is bigger than the pressure inside significantly, and the distribution of pressure of each step is similar with each other. The joint energy dissipation of step spillway and the stilling basin behaves well and it can be a reference for the similar projects. The related hydraulic parameters from the numerical simulation agree well with the results of the experiment, and the detailed information of the flow field can be obtained from the three-dimensional turbulence numerical simulation, which suggests it is reliable for adopting the above mentioned turbulence model to compute the flow field of the stepped spillway.