管内水流冲击滞留气团的CFD模拟方法验证

Verification of CFD Simulation on the Filling of Pipeline with Standing Air Mass

在输/排水管道的快速填充过程中常会出现含滞留气团的复杂气—水两相瞬变流,极有可能引发异常的压力波动,从而导致严重的水力过载甚至爆管事故。目前,对于这种特殊瞬变流现象的研究基本采用一维方法或观测视角,无法准确反映气团的动态特性。为此,基于计算流体力学(CFD)模拟方法,采用5种湍流模型对该瞬变流问题进行了二维(2D)数值模拟,并将其瞬态压力、水气耦合分布模拟与试验结果进行比较。结果表明,CFD模拟方法能有效模拟水气分布及压力动态变化;标准κ-ε和标准κ-ω模型计算的最大压力误差较小,RNG模型的压力波动周期吻合度最好,两种κ-ω模型的气团模拟效果欠佳。

During the rapid filling process in the pipelines,complex air-water two-phase transient flow often happened and it is probable to cause abnormal pressure fluctuations,which leads to severe hydraulic overload or pipe explosion accident.At present,the study of this special transient phenomenon is based on one-dimensional method or observation view.So,the air dynamic characteristics cannot be accurately reflected.Based on computational fluid dynamics（CFD）method,five kinds of turbulence models were introduced to simulate two-dimensional transient flow.The simulated transient pressure and air-water interaction were compared with the experimental results.The results show that the CFD method can effectively simulate air-water distribution and dynamic change of the pressure.The maximum air pressures calculated by the standardκ-εand standardκ-ωturbulence models are in better agreement with the experimental data.RNG model is best in simulating the pressure fluctuation cycle.Two kinds ofκ-ωturbulence models are not suitable for the simulation of current rush to air mass.