Numerical Simulation and Analysis of Artificial Aeration Ecological Purification System Based on CFD (Computational Fluid Dynamics)

Abstract. In recent years, water environment and aquatic ecosystems have been a certain degree of damage. The serious water pollution is one of the difficult problems in our country to realize the sustainable development and utilization of water resources. Therefore, how to effectively control wastewater pollution has become the key problem to be solved. At present, Chinese widely used artificial wetland system processing technology, although the technology has received a large number of test data and empirical parameters, the technology still exists many problems in the actual engineering project, such as easily affected by the hydraulic load and water distribution, producing clogging and saturation, etc. Therefore, this research is aimed at the main problems existing in constructed wetlands, proposing artificial ecological aeration purification system. This research simulating the artificial ecological aeration project in Yizhuang River of Jiaxing Shijiuyang ecological wetland demonstration project based on computational fluid dynamics (CFD), analyzing and coupling the turbulence model of liquid-solid two-phase mixture and activated sludge model 2,establishing a turbulence kinetic model of liquid-solid two-phase in the aeration channel. By modeling for each pollutant, achieving the simulation of water quality concentration distribution in the river, verifying the accuracy of the model based on the actual measurement data, discussing the evolution of the velocity field around the aerator and its multiphase flow Aeration process, considering the influence of dissolved oxygen concentration to the system combined with the velocity vector figure, the gas volume fraction distribution figure and so on, providing the theory basis and technical support for further optimization direction and the better parameter to the system.