河流交汇区污染物扩散数值模拟研究  

Numerical Simulation Research on Pollutant Diffusion in the Confluence Area of Rivers

作　　者：杨志山[1] 米潭 姚建 张弢 YANG Zhishan;MI Tan;YAO Jian;ZHANG Tao(College of Architecture and Environment,Sichuan University,Chengdu 610065,China;Chengdu Research and Monitoring Institute of ecological environment,Chengdu 610072,China)

机构地区：[1]四川大学建筑与环境学院,四川成都610065 [2]成都市生态环境科研监测所,四川成都610072

出　　处：《华北水利水电大学学报（自然科学版）》2021年第6期86-92,共7页Journal of North China University of Water Resources and Electric Power：Natural Science Edition

基　　金：国家重点研发计划重点专项(2018YFC1900103)。

摘　　要：为分析自然河流交汇区不同汇流比下污染物的扩散特征,通过建立平面二维自由表面流MIKE 21 FM模型,对中国西南中小河流石亭江与其支流鸭子江的河流交汇区不同汇流比情况进行COD和氨氮扩散情况的数值模拟研究。当汇流比分别为0.50、0.67时,COD形成的污染带面积较汇流比为0.33时分别增加30.0%、93.8%,COD纵向质量浓度梯度分别降低1.8%、3.2%,横向质量浓度梯度分别增加1.1%、2.3%,交汇后未出现明显的COD均匀混合位置;氨氮污染带面积较汇流比为0.33时分别增加4.4%、10.6%,氨氮纵向质量浓度梯度分别降低1.9%、3.3%,横向质量浓度梯度分别增加2.3%、3.3%,在汇流比为0.33、0.50、0.67时分别于1820、1960、2050 m处均匀混合。研究明确了交汇区不同汇流比情况下的污染物扩散特征,可为流域水环境精细化管理提供支持,同时,MIKE 21 FM模型能较好地反映自然河流交汇区污染物浓度场分布,可应用于自然河流交汇区污染物扩散研究。In order to analyze the diffusion characteristics of pollutants under different confluence ratios in the confluence area of natural rivers,a plane two-dimensional free surface flow MIKE 21 FM model was established to simulate the diffu-sion of COD and ammonia nitrogen in the confluence area of Shi Ting River and Ya Zi River,a small and medium-sized River in Southwest China.When the confluence ratio is 0.50 and 0.67,the pollution zone area formed by COD increases by 30.0%and 93.8%respectively compared with that when the confluence ratio is 0.33.The longitudinal mass concentra-tion gradient of COD decreased by 1.8%and 3.2%respectively,and the transverse mass concentration gradient increased by 1.1%and 2.3%respectively.There is no obvious cod uniform mixing position after intersection.Compared with the concentration ratio of 0.33,the area of ammonia nitrogen pollution zone increased by 4.4%and 10.6%respectively,and the longitudinal mass concentration gradient of ammonia nitrogen decreased by 1.9%and 3.3%respectively.The trans-verse mass concentration gradient increased by 2.3%and 3.3%respectively.When the confluence ratio was 0.33,0.50 and 0.67,it was evenly mixed at 1820,1960 and 2050 m respectively.The study defines the pollutant diffusion character-istics under different concentration ratios in the intersection area,which can provide support for the fine management of wa-ter environment in the basin.At the same time,Mike 21 FM model can better reflect the distribution of pollutant concentra-tion field in the intersection area of natural rivers,and can be applied to the study of pollutant diffusion in the confluence area of natural rivers.

关 键 词：河流交汇区 MIKE 21 FM模型 污染物扩散 数值模拟 

分 类 号：X143[环境科学与工程—环境科学]