中文摘要：

掺气减蚀段流场为水气两相流,掺气空腔后水气混掺剧烈,数值模拟难度大,尤其是临底掺气浓度,查阅的文献中计算结果普遍偏大。结合泄洪洞掺气设施对掺气水流进行数值模拟研究,通过二维流场模拟对不同的两相流模型和特征参数进行比较,总结出掺气水流的模拟方法。采用Eulerian模型对掺气水流进行三维全域流场模拟,对比分析水面线、通气量、掺气浓度等水力参数,计算结果与实测数据吻合较好,临底掺气浓度分布与实际情况相符,突破了掺气水流的模拟瓶颈,该模拟方法可为实际工程服务。

英文摘要：

Aerated flow downstream the air cavity is a type of two-phase flow where air is strongly mixed with water. Numerical simulation of such flow is very difficult, especially the calculations of air concentration near tunnel bottom are inaccurate as shown in many of the previous studies. This paper presents a study on numerical simulation of the aerated flow downstream a bottom aerator of hydraulic tunnel. Different models of two-phase flow and characteristic parameters in two-dimensional simulations are compared and simulation methods of aerated flow summarized. Then, an Eulerian model is used for simulation of three-dimensional aerated flows. Analysis and comparison of the calculated water surface profiles, aeration rate, and air concentration, shows a good agreement of the present calculations with measurements. Particularly, the concentration distribution near the base slab is reasonable, indicating that the numerical simulation of aerated flow is feasible and the presented simulation method can be applied in design of practical hydraulic projects.