Numerical Simulation Study On Contaminants Transport And Diffusion Law In River

At present, water pollution is worse and worse, which has had a bad affect on the people's daily life and economic development. To harness and administer the contaminative river has become an environmental problem of interest to the people. The research on the quality of the river and migratory principle of contaminants in the river will provide theoretical reference for the prevention of river pollution.River water quality model is an efficient tool to preview the varying rules that water quality varies with time and space. If the nature river is very long and the depth and river width are small relatively, river water quality model can be simplified into one dimension model. This paper builds the basic equation of one dimension permanent current river water quality model based on researching the transport and diffusion of contaminants in the river and its effect factors. By means of an implicit finite differential method, a calculation of this equation is given. We choose biochemical oxygen demand (BOD) as the forecast factor and compare the numerical modeling results with the QUAL2K model soft's simulation results which was developed by the U.S. Environmental protection Agency (EPA) through an example. The results indicate that the river water quality model we build is efficient and convenient to simulate the transport and diffusion rules of contaminants in the permanent current.Water temperature is a basic parameter of integrated evaluation of water environmental quality and also is an important influencing factor of water quality parameters. So building water temperatue model to research and forecast the water temperature variation regularity is an important basis in water environment analysis. This paper introduces the influencing factors of river water temperature change and gives emphasis to expand heat exchange between water surface and atmosphere. Based on these studies, this thesis builds one dimension river water temperature model and uses Eckel-Reuter numerical integration method to solve the model equation. We simulate the variation regularity of longitudinal temperature and the diel temperature of the river end. The present results compare favorably with those obtained by QUAL2K model soft. We also arrive at...