Analytic modeling of soot nucleation under fuel rich conditions

The objective of the present research is to construct a soot nucleation model according to a proposed chemical kinetic scheme to delineate quantitatively the nucleation mechanism in the soot formation process. Instead of following the traditional views which generally associate sooting with the homogeneous nucleation process in phase transformation or polymerization, we choose a chemical kinetic approach. In our proposed scheme the number of carbon atoms in the intermediate species between the fuel molecule and soot nuclei is continuously increased by radical additions. The number of hydrogen atoms in the intermediate species on the other hand is steadily decreased by radical dehydrogenation. When the number of carbon atoms in each of the intermediate molecules has exceeded a certain limit and the number of hydrogen atoms has fallen below a certain level, they may coagulate with one and another to form a larger molecule which is regarded as the initial soot nuclei in the present theory. Further coagulation and surface growth of the nuclei will lead to observable soot particles.