Effects of Adiabatic Temperature and Chemical Composition on Soot Formation in Laminar Diffusion Flames

摘要

This paper studies the effects of adiabatic temperature and chemical composition on the formation of nanoparticles in a laminar diffusion flame. Time resolved laser induced fluorescence and laser induced incandescence are employed to study concentration, size and growth of particles. Three axisymmetric coflow laminar diffusion flames are investigated by laser diagnostics. The base flame is a jet of 60% ethylene and 40% nitrogen. Second flame is 60% ethylene and 40% carbon dioxide. Third flame is 60% ethylene and 40% argon. Two categories of particles are selectively excited and their responses are analyzed. Three flames have comparable adiabatic temperatures. Nitrogen and argon diluted flames have quite similar response in all cases. As per results, soot concentration in carbon dioxide diluted flame would be significantly less than that of in other two flames. The size of particles in carbon dioxide diluted flame is less than that of in other two flames. The difference in carbon dioxide diluted flames is due to different chemical reactions involved.