低弗劳德数趾墩悬栅联合消能工数值模拟

针对低弗劳德数水流在消力池内极易形成弱水跃且水面大幅波动的问题,在低弗劳德数情况下,利用RNGκ-ε紊流模型,分别对趾墩悬栅联合消能工与单一悬栅消能工所处流场进行数值模拟,系统分析了水深沿程变化及流速分布规律,得到联合消能结构作用下消力池内部水流流态及过栅绕流涡旋分布。结果表明,联合消能工能增大回流区漩涡尺度,加剧水流卷吸掺混强度,大幅提高掺气浓度,迫使跃前断面向下游推移,相对推移比接近26%,淹没度下降约10%左右,从而显著降低陡坡水流脉动;悬栅附近涡群具有更强的漩涡运动,主、回流间紊动混掺加剧,增强了下泄水流能量耗散。研究结果为同类工程中解决消能防冲问题提供了新思路和参考依据。

Numerical Simulation of Joint Energy Dissipation of Diversion Pier and Suspended Grid with Low Froude Number

The low Froude number water flow in the stilling basin is easy to form a weak hydraulic jump and water surface fluctuations.Numerical simulation of flow filed around diversion pier and suspended grid joint energy dissipator and the single suspended grid were analyzed by using RNGκ-εturbulence model.The variation of water depth along the way and the law of velocity distribution were analyzed.And the internal water flow pattern and characteristics of vortex pattern around the suspended grid were obtained under action of joint energy dissipator.The results show that the joint energy dissipator can increase the vortex scale of the recirculation zone,aggravate the mixing intensity of water entrainment,and increase the aeration concentration greatly.In addition,the joint energy dissipator makes the hydraulic jump move toward the downstream close to 26%,and the submergence decreases by 10%,which can significantly reduce the fluctuating intensity of turbulence at the steep slope in stilling basin.The vortices exhibit stronger swirl motion in the vicinity of the suspension grid,which form a highly complex turbulent flow and enhance the effect of energy dissipation.The research results provide new approaches for energy dissipation and erosion control of similar projects.