Soot formation and evolution in RP-3 kerosene inverse diffusion flames: Effects of flow rates and dimethyl carbonate additions

RP-3 kerosene fuel is the dominant hydrocarbon fuel used in civilian aeroplanes in China. In this study, the effects of fuel flow rates and dimethyl carbonate additions on the formation and evolution of young soot particle collected from RP-3 kerosene in inverse diffusion flames were studied comprehensively by several methods. Physical properties (nanostructures) of soot particles were evaluated by low-resolution transmission electron (TEM) microscopy, high resolution transmission electron microscopy (HRTEM), X-ray Diffraction (XRD) spectroscopy, and Raman spectroscopy. Chemical properties (oxidation reactivity and surface oxygen contents) of soot particles were studied over thermogravimetric analyzer (TGA) and X-ray photoelectron spectroscopy (XPS). When the fuel flow rate increased and dimethyl carbonate addition ratio decreased, the soot particles and aggregates were found to form a lot and grow faster with bigger primary particle diameter. The HRTEM, XRD, and Raman analyses have shown that the disorder and turbostratic structure with shorter fringe length and longer tortuosity were increased, which indicated higher oxidation reactivity rates, as the fuel flow rate and dimethyl carbonate addition ratio increased. The surface oxygen contents were found to decrease as the fuel flow rate increased, while were shown to increase as the dimethyl carbonate addition ratio increased.