Numerical Simulation To The Wastewater's Side Discharges Using Nonlinear K-ε Turbulence Model

The wastewater from the city residences and the industry facilities gets more and more these year because of the city modernization and the industry development. Thus, preventing environment from being polluted by wastewater gets to be a more and more important aspect of environment protection. In order to do this, the problem on one hand, is to study about the efficient ways to treat the wastewater, and on another, is to effectively regulate the amount of wastewater's discharging to environment.In the past, people used to control the discharge of wastewater in the practical ways, for example, measure the water quality of receiving environment, check it with the criterion, and then come back to control the discharging amount. This kind of methods is practical, but it's holding fairly large spending. Nowadays, with the development of computational fluid dynamics, the procedure of wastewater discharge and the concentration distribution of the waste could be easily got by numerical simulation. By this means, a general idea about the diffusion of wastewater in the receiving waters can be got before the actual measurement, which helps to cut down the measurement spending and makes the regulation of wastewater discharge more convenient.As a typical case in the field of numerical simulation to the wastewater discharge, the problem of side discharge into a river is widely studied by researchers. It is a problem of convection mass transfer and could be most probably a problem ofturbulence in real condition, so the turbulence model acts an important role in the numerical simulation. In most cases in current researches, the standard k - ε turbulence model is adopted. Although the standard k-ε turbulence model has been proved to be a model adapting a large range of conditions, it does not fit in with the cases where the normal Reynold stress of fluid is of great importance. As generally known, these cases include at least some cases where recirculation or secondary flow takes place. In order to make the simulation adaptive in a greater degree to the real conditions, in this dissertation a more superior turbulence model known as nonlinear k-ε model is adopted for calculation. The finite volume method is used to transform the controlling differential equations into the algebra ones, and the semi-implicit method for pressure-linked equations (SIMPLE) is used to solve the pressure. A reasonable numerical simulation result is got, and then is compared with the experimental data as well as the result got by using standard k-ε model.