基于分形理论的柴油机排放颗粒物生长过程研究

项目名称： 基于分形理论的柴油机排放颗粒物生长过程研究

项目编号： No.51276132

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 能源与动力工程

项目作者： 魏明锐

作者单位： 武汉理工大学

项目金额： 70万元

中文摘要： 碳烟颗粒物是柴油机排放的主要污染物，目前对其形成机理的认识尚且不足，本项目基于现代分形理论对此进行深入研究，主要涉及：1.基于均相饱和理论构建颗粒物初始胚核的成核模型，获得初始胚核的成核速率、临界成核直径和时空分布；2.利用分形理论对成核后颗粒物的运动碰撞、凝聚、表面沉积、聚集体断裂等动力学演变过程建立物理数学模型，确立颗粒物的分形特征与其生长环境如环境温度、压力、组分浓度、输运参数和流态等因素之间的关系。据此研究燃烧系统的结构、工况、燃料、火焰结构对颗粒物生长的影响，获得颗粒物形貌结构、聚集状态等信息，探讨其分形结构的形成机制；3.在实验台架上对柴油机颗粒物进行抽样和电镜分析，结合图像分析技术，确定颗粒的分形结构特征。 将分形理论应用于柴油机颗粒物生长过程的研究，研究成果可为改善燃烧和研发先进的颗粒物排放控制技术提供理论依据，对降低燃烧源颗粒物排放、解决环境污染问题具有重要的科学意义。

中文关键词： 柴油机；碳烟颗粒；分形维数；成核；燃料添加

英文摘要： Particle Matter（PM）is the main pollutants in the exhaust of diesel engine. However, the understanding of the PM formation is still not enough now. The present research investigates deeply the PM formation process based on modern fractal theory, the main contents are as follows: 1. The model of primary particles nucleation is established based on the homogeneous saturated theory, by which the rate of nucleation, the critical diameter of nucleation and the distribution in spatial-temporal of primary particles are obtained. 2. The physical and mathematical model is established by using fractal theory on the dynamic evolution process of particles after the nucleation, including particles collision, coagulation, surface deposition, aggregates fragmentation etc. and the relationship between the fractal structure characteristics of particles and their growth environment such as ambient temperature, pressure, the concentration of fuel components, and fluid transport parameters and flowing state are analyzed .Based on the above, the effects of the combustion systems structure, operating conditions, fuel and the flame structure on the growth of particles are studied, by which the morphology and aggregation state of the particles are obtained. Simultaneously, the formation mechanism of the fractal structure are explored. 3

英文关键词： diesel engine；soot particles；fractal dimension；nucleation；fuel additive