齿墩式内消能工的水力特性数值模拟研究

Numerical Simulation of Hydraulic Characteristic of Tooth-block Inner Energy Dissipaters

为了进一步研究齿墩式内消能工的水力特性,采用数值模拟方法,利用Gambit软件建立齿墩式内消能工的计算网格,借助Fluent软件中RNGκ-ε双方程紊流模型对水流流动进行数值模拟,物理模型试验结果与数值模拟结果吻合较好,并在此基础上利用数值模拟方法分析了齿墩式内消能工的压强、流速、消能率及过流能力等水力特性。结果表明,在齿墩入口处管道中心附近的压强明显小于管壁的压强,进入齿墩段,压强骤降形成低压区;在齿墩下游0.1 D(D为管道直径)处压强降到最低,之后开始恢复,并逐渐趋于平稳,压强恢复区长度约为3 D;在齿墩末端正后方形成漩涡回流区,漩涡长度约为1.2 D,之后流速分布趋于均匀;与相同面积收缩比的洞塞式内消能工相比,虽然消能率相应降低,但其流量系数的增幅大于消能率的减幅,有利于缓解过流能力与消能效果的矛盾。

In order to further study on the hydraulic characteristics of tooth pier inner dissipator,based on the numerical simulation,the Gambit software was used to build computational grid.Then RNGκ-εturbulence model in Fluent software was adopted to simulate the water flow filed.Compared with the results of physical model,good agreement had been achieved.On this basis,the mathematical model was used to calculate and analyze the pressure,flow rate,energy dissipation rate and conveyance capacity of tooth pier inner dissipater.The results show that the pressure at the center of the pipe was significantly less than the pressure near the wall in the tooth pie entrance.After entering the segment of tooth pier,pressure declined sharply at the inlet and formed a low pressure area.The minimum pressure appeared at 0.1times diameter away from outlet of the tooth block;then the pressure rose gradually and recovered stably at 3times diameter.The vortex reflux area formed at the posterior epidural space of the end of tooth pier and the length was approximate1.2times diameter;then the velocity distribution tended to be uniform.Compared with the same area of the contraction ratio of the plug energy dissipator,the rate of energy dissipation reduced accordingly.But the increase of the flow coefficient was greater than the damping of energy dissipation rate,which is in favor of relieving the contradiction between flow capacity and energy dissipation effect.