Simulation of sub-micron particle formation and growth during combustion processes

Abstract

Sub-micron particle formation and growth during combustion processes is very complex because of its strong uncertainty and randomness. A model to simulate the sub-micron particle formation and growth during the combustion process is developed based on the gas kinetic theory and is expressed by the vapor concentration changes and particle loading changes, which reflects effect characteristics of different mechanism ( nucleation, condensation and coagulation 1 in particle formation processes. The developed characteristic time is used to token the three mechanisms. It is thought that environmental temperature and pressure, vapor temperature and critical pressure are important factors influencing the sub-micron particle formation and growth. The sub-micron particle formation processes under different conditions are studied and the effect characteristics of these mechanisms are analyzed, which show that the nucleation, condensation, and coagulation occur simultaneously during the sub-micron particle formation and growth process. Nucleation contributes to the sub-micron particle formation, while condensation and coagulation is helpful to the growth of the particle size.