CFD Modelling of the Transport of Soluble Pollutants from Sewer Networks to Surface Flows during Urban Flood Events
CFD Modelling of the Transport of Soluble Pollutants from Sewer Networks to Surface Flows during Urban Flood Events
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DOI：
10.3390/w12092514
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发表时间：
2020-09
期刊：
影响因子：
3.4
通讯作者：
M. Beg;M. Rubinato;R. Carvalho;J. Shucksmith
中科院分区：
文献类型：
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作者：
M. Beg;M. Rubinato;R. Carvalho;J. Shucksmith
城市排水系统超负荷是洪水致病污染的潜在来源。虽然以前的一些研究调查了洪水期间净下水道到地表通过沙井和沟渠的水力流量，但目前还缺乏对污染物如何从下水道网络转移到地表洪水的了解。本文提出了一种三维CFD模型，用于定量计算具有复杂相互作用的管流和面流的水工建筑物中的水流和溶质质量交换。将该模型与一个大型物理模型的实验数据集进行了比较，该模型旨在研究洪水模拟过程中管道/表面的相互作用。结果表明，CFD模型较准确地描述了实验装置中管道与地面的流动分配和溶质在沙井中的运移过程。经过验证，该模型被用来阐明描述从管网进入地表流动的质量流量的关键时间尺度。数值实验表明，在充分混合的溶质到达交换结构后，溶质交换到表面的质量逐渐增长到相当于流动分配比的值，并伴随着相关的时间尺度，是流动条件和沙井内扩散传输的函数。
Surcharging urban drainage systems are a potential source of pathogenic contamination of floodwater. While a number of previous studies have investigated net sewer to surface hydraulic flow rates through manholes and gullies during flood events, an understanding of how pollutants move from sewer networks to surface flood water is currently lacking. This paper presents a 3D CFD model to quantify flow and solute mass exchange through hydraulic structures featuring complex interacting pipe and surface flows commonly associated with urban flood events. The model is compared against experimental datasets from a large-scale physical model designed to study pipe/surface interactions during flood simulations. Results show that the CFD model accurately describes pipe to surface flow partition and solute transport processes through the manhole in the experimental setup. After validation, the model is used to elucidate key timescales which describe mass flow rates entering surface flows from pipe networks. Numerical experiments show that following arrival of a well-mixed solute at the exchange structure, solute mass exchange to the surface grows asymptotically to a value equivalent to the ratio of flow partition, with associated timescales a function of the flow conditions and diffusive transport inside the manhole.