中文摘要：

基于弹射凝聚模型构建碳烟颗粒间碰撞的物理模型，采用蒙特卡洛方法构建碳烟颗粒凝聚和表面生长的数学模型并进行数值模拟。引入分形维数、包容半径和凝聚体体积来描述凝聚体分形生长特征，分析表面生长过程对这些参量的影响。对比了不同环境压力和温度对碰撞频率、粒径增长率和分形维数的影响。最后通过枝接过程的模拟，获得了链状凝聚体的形貌特征，并与真实的碳烟照片进行对比，结果表明，枝接过程模拟出的碳烟结构更接近于尾气中真实的链状碳烟形貌。

英文摘要：

The physical model for the collision between soot particles is established based on ballistic aggre- gation model, and Monte Carlo method is used to build the mathematical model for soot particle aggregation and sur- face growth, with numerical simulation conducted. Fractal dimension, enclosing radius and aggregate volume are in- troduced to describe the fractal growth characteristics of aggregates, and the effects of surface growth process on these parameters are analyzed. The effects of different ambient pressures and temperatures on the collision frequen- cy, the growth rate of particle size, and fractal dimension are compared. Finally through a simulation on coalescence process, the morphological feature of chain-like aggregates is obtained and compared with real soot photos. The re- sults show that the soot structure simulated by coalescence process is closer to real morphology of chain-like soot particles in exhaust gas.