Numerical investigation of soot phenomenon in a CI engine

Nowadays, a considerable part of the energy is the result of the combustion of hydrocarbon fuels in combustion systems. Therefore, efforts to improve and modify combustion processes and reduce the undesirable byproducts are of great concern. Among all the efforts made to improve the performance of combustion systems including reduction of pollutants, reduction of soot emissions has received special attention. This is due to the fact that soot emission is one of the major pollutants that have irreparable effects on human health, and affects the quality of life. Since the first step to reduce the soot pollution is to provide a comprehensive overview of its structure, mechanisms and also the effective parameters of its production, in this study, the phenomenon of soot formation and oxidation are investigated using one of the multi-step models presented for the formation and oxidation of soot to identify the behavior and parameters affecting soot formation. Numerical modeling of this phenomenon is carried out using KIVA-3V code. The results of the simulation are validated using the experimental data of pressure and the amount of soot formed in the combustion chamber of a two-stroke diesel engine with a direct injection system. Soot characteristics i.e., mass, volume and volume fraction of soot, species concentration, soot concentration, particle number density, average particle diameter, and the time and place of soot content in the combustion chamber are discussed as outputs of the model. The results show good agreement with the experimental data.