溢流堰表孔弧形闸门开启过程非恒定流水力特性

Analysis of hydraulic characteristics of unsteady flow during opening of radial gate located on overflow weir

采用RNGκ-ε紊流模型结合动网格技术对某水利工程Y型宽尾墩泄洪表孔弧形闸门开启过程进行了三维动态数值模拟研究。为了解闸门开启过程中各相对开度的水力要素特性,采用6种不同的开启总时间,给出各开启总时间对应的闸后流速、压强等水力要素对闸门开启速度的依赖关系,并定义了反弧及消力池3个压强分布区域。研究表明,闸门开启总时间较小时,闸后水流的滞后效应明显,各对应相对开度时闸后水面线偏低;开启过程中溢流堰反弧处最大流速、冲击区最大压强等都会远大于恒定情况时的对应值。冲击区最大压强及其与调节区平均压强的差值随开启速度的增大迅速增加,且需经过较长时间才逐渐回到正常值。开启速度较小时,各水力要素增加较为平缓。将闸后水面线等计算结果与试验结果进行对比,吻合良好,验证了数值方法的可靠性,可为类似水工闸门运行提供借鉴。

The RNG κ-ε turbulent model and dynamic mesh technology were applied to simulation of the unsteady flow of the flaring gate pier and the stilling basin during the radial gate opening. Six different total opening times were used to achieve the detailed hydraulic properties of different opening velocities. The opening velocities of the radial gate were homogeneous of every total opening time. The relationships between the opening velocities and pressures,flow velocities and other hydraulic characteristics were obtained by using six corresponding total opening times. Hysteresis effect was apparent while the total opening time was relatively small,and a water surface profile corresponding to different relative openings was also lower than those of other total opening times. The maximum flow velocity appeared at the ogee section of the overflow weir at the opening process no matter which total opening time was. The maximum velocity and the pressure on the impact region were much larger than the corresponding value at a constant situation. The slab of the ogee section and stilling basin was divided into three regions according to the distribution of pressurs; the relationships between the maximum pressure and the opening velocity was obtained. The velocities and the maximum pressure on the impact region in the stilling basin were much higher than those corresponding to the constant conditions while the opening velocities were relatively lower. The maximum pressure and differences between the maximum pressure on the impact region and an average pressure of the adjusting region increased with the increasing of the opening velocities,and fell to a normal value after long time. A gentle increase in pressures and other hydraulic characteristics would appear under the lower opening velocities.The water surface profile and other results of numerical simulation were in good agreement with the model test data,which shows that the numerical method is reliable. The analysis results can provide an important basis for operation of the similar radial gate located on the hydroproject.