Wang Z.-Y.,North University of China |
Du X.-J.,North University of China |
Chen L.,National Automobile Quality Supervision Test Center Xiangyang
Xitong Fangzhen Xuebao / Journal of System Simulation | Year: 2012
In order to study the diffusion characteristics of automotive emission NO x under conditions of the factors, such as wind velocity, ambient temperature, automotive exhaust thermal driving, ground thermal radiation and vehicle drag effect, affecting the dispersion of automotive emissions, the CFD simulation models of automobile emission NO x dispersion in real atmospheric environment were built. The numerical simulation of three-dimensional unsteady turbulent flow was achieved and the diffusion characteristics of automotive emission NO x with which affected by the every environmental factor were obtained. The results show that the numerical result accords relatively with the measured concentration by means of comparing with each other, and the dispersion characteristic of the pollutant can be well simulated with the models. The volume concentration of NO x shows approximately decreasing characteristics of exponential function with the increase of vertical height above the emission source. With the increase of the wind speed, NO x is easy to spread to the down-stream along the wind direction. Meanwhile, with the increase of atmospheric environment temperature, ground surface temperature, exhaust gas temperature and vehicle velocity, NO x is easy to spread to the sky. The correlation of factors affecting the automotive exhaust pollutant diffusion was analyzed with the grey correlation theory and the correlation sequence is atmospheric wind speed > vehicle velocity > ground surface temperature > atmospheric environment temperature > exhaust gas temperature, which can provide theoretical basis for the moving and dispersion of the automotive exhaust pollutants and modifying the coefficient of the theoretical models of atmospheric pollutants dispersion.