汽车排气尾流中微粒分布及其变化特性的研究

根据微粒核化、凝并及凝结模型对汽车排气尾流中微粒分布的变化特性进行了分析.结果表明,微粒的核化增加了排气尾流中超细微粒的数量;微粒的凝并和凝结将改变排气尾流中的微粒分布.在核化、凝并及凝结过程同时存在时,核化对微粒分布的影响相对较小,微粒分布的变化主要受凝并和凝结的作用.在排气管出口处,微粒的核化、凝并及凝结过程比较剧烈,微粒分布变化较大;随着距排气管出口距离的增加,微粒演变逐渐减弱.研究工作可以为汽车排放控制策略的确定以及汽车微粒对人体健康影响的研究提供依据.

Study on the Evolution Characteristics of the Particle Distribution in the Vehicle Exhaust Plume

The evolution characteristics of particle distribution in the vehicle exhaust plume have been investigated based on the models of nucleation, coagulation and condensation of particles. The simulated results showed that nucleation created a large number of new nano-particles, and coagulation and condensation changed the distribution of particles in the vehicle exhaust plume. The effect of nucleation on the distribution of exhaust particles was weaker, and the distribution of exhaust particles was affected mainly by the effect of coagulation and condensation. The process of nucleation, coagulation and condensation was intense near the exit of the tailpipe and the variation of the particle distribution with time was strong. With the increase of the distance from the exit of the tailpipe, the evolution of exhaust particles got weaker. This work can provide much more information necessary for the establishment of vehicle emission control strategies and the study of the effect of vehicle particles on the human health.