基于非恒定流的底泥污染物释放的数值模拟

Numerical Simulation of Pollutant Release from Sediment Based on Unsteady Flow

当外源污染受到控制后,河流与湖泊底泥中的污染物可能会引起上覆水的再次污染。天然河流和湖泊中的水流,由于各种因素的影响,流速等参数常常是随时间变化的。本文在上覆水流动不致底泥起动悬浮的条件下,数值模拟研究单向非恒定流中污染物通过底泥-上覆水界面的释放规律。采用k-ε湍流模型计算上覆水的流动;采用Darcy定律描述多孔介质中的渗流,耦合计算上覆水和底泥中孔隙水的非恒定流动,在此基础上,计算了污染物溶质在上覆水体和底泥孔隙水中输运过程。数值研究结果表明,与恒定流相比较,非恒定流中上覆水中污染物浓度峰值较大,从而影响上覆水体的水质。

When external pollution is controlled, pollutants in sediments of rivers and lakes may cause re-contamination of overlying water. Flows in natural rivers and lakes, due to various factors, flow rate and other parameters often change over time. In this paper, under the condition that the overlying water flow does not initiate the suspension of the sediment, the release of contaminants through the sediment-overlying water interface in one-way unsteady flow is numerically simulated. The turbulence model was used to calculate the flow of overlying water. The Darcy＇s law was used to describe the seepage flow in porous media and the coupled calculation of the unsteady flow of water in the overlying water and the pore water in the sediment. On this basis, the pollutant solute in the overlying water and the bottom was calculated. Mud pore water transport process. The numerical results show that, compared with the constant flow, the concentration of pollutants in the overlying water in the unsteady flow has a peak value, which affects the water quality of the overlying water.