多层多股跌扩型底流消能的数值模拟研究

基于RNG k-ε紊流模型和VOF自由表面追踪法,采用非均匀结构网格技术,建立了三维紊流数学模型,对跌扩型底流消能工进行高精度数值计算。讨论了不同泄流方案下游消力池内水力特性的变化,得出如下结论:(1)不同工况下,下游消力池内水流紊动剧烈,其临底流速较大值相对集中在消力池前段;(2)当高低坎联合泄流时,可形成多层多股射流,流速梯度改变差异较大,各股主流掺混合并速度更快;(3)就消能率而言,高低坎联合泄流紊动能消逝比单独泄流更迅速,消能效果明显。

Numerical simulation on bottom-flow energy dissipation by multi-strand and multi-level submerged jets with vertical drop and sudden enlargement

Based on RNG k-ε turbulent model and VOF method，a high-precision numerical calculation is made herein on the bottom-flow energy dissipator by multi-strand and multi-level submerged jets with vertical drop and sudden enlargement by the technology of non-uniform structural grid. The changes of the hydraulic characteristics in the downstream plunge pool under various energy dissipation schemes are discussed and the following conclusion is obtained：（1）under different operation conditions，the flow is strongly turbulent within the downstream plunge pool，the velocity of the near-bottom flow with higher value is always concentrated in the fore-section of the pool；（2）multi-strand and multi-level submerged jets are to be formed during the joint-discharge with both the higher and the lower sills along with larger changing differences among the flow velocity gradients and higher mixing speeds of all the main jet-flows；（3）So far as the energy dissipation ratio is concerned，the dissipation of turbulent energy during the joint-discharge is more faster than that during the single discharge with an obvious energy dissipation effect.