复杂频繁突变断面输水隧洞水力特性的数值模拟研究

Numerical Simulation of Hydraulic Characteristics of Water Conveyance Tunnel with Complex and Abrupt Sections

为研究断面频繁突变对TBM超长输水隧洞内的水流流态和水头损失造成的影响,结合工程实例,通过OpenFOAM开源软件对隧洞内的水流流态进行三维数值模拟,主要从洞内水面线变化、水头损失及时均流速场等水力要素总结出断面频繁突变对水流流态和水头损失影响的变化规律。研究表明,在设计流量下,该研究区段的断面频繁突变共造成局部水头损失91 mm,平均每个突变约造成5.06 mm的水头损失;且当隧洞断面比大于5.2/5.5时,洞内时均流速波动范围较小,无明显的回流区产生,水流流态良好。

In order to study the impact of abrupt sections on the flow pattern and head loss in the TBM ultra-long water conveyance tunnel,combined with engineering examples,the OpenFOAM open source software was used to numerically simulate the three-dimensional water flow pattern in the tunnel.It mainly summarized the law of abrupt sections on the flow pattern and water head loss from the changes of the water surface line in the tunnel,the head loss,and the time-averaged velocity field.The study shows that under the design flow,frequent abrupt sections cause a total of 97 mm local head loss,and an average each sudden change causes a head loss of about 5.38 mm;When the cross-sectional ratio is greater than 5.2/5.5 inside the cave,the fluctuation range of the flow velocity is small,and the flow pattern is good.