| Exhaust pollution is one of the most important factors to decide the diesel engine development in the future, especially the particle matter(PM). So it is significantly to research the harm of PM and control by research formation mechanism and physical characteristic. However, the formation mechanism is not really clearly now. So a deeply study on formation mechanism of PM is more necessary for the application and theory research of diesel engine.Based on the formation process of PM undergo, a review of an array of studies on PM formation mechanism is presented, based on which the gas phase reaction kinetics and solid particle kinetics characteristics are concluded. The SEM micrographs of PM obvious show its fractal structure.The dynamic Monte Carlo method to simulate the formation of diesel particle matter is discussed. The growth processes such as collision trajectory, surface growth, surface oxidation, coalescence are built in the model. The methods of Monte Carlo to calculate structure parameters such as fractal dimension, volume and surface are depict. Also the total collision time and the amount of time between to collision are calculated.The dynamic Monte Carlo method is solved numerically. The modality of PM, formed by aggregation and coalescence, is displayed. And the comparison with the chained-like PM from the exhaust of diesel engine. The influence of pressure and temperature on PM growing process is analyzed, by which the relationship between the fractal dimension of PM and the influence factors is obtained. Modified the model by the shape gene, calculated and compared the coalescence and aggregation, respectively.At last, several methods are introduced to calculate the fractal dimension. In this dissertation, the fractal dimension of coalescence and aggregator are calculated by box counting algorithm, respectively.
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