Effects of Ambient O ₂ Concentration and Pressure on Combustion Characteristics of Diesel Spray

Effect of the ambient O₂ concentration and pressure on the spray combustion characteristics of diesel fuel was experimentally examined using a high-temperature, high-pressure combustion vessel. The sequential images were captured by using a high-speed color video camera and were analyzed using the two color method to quantify the temporal variation of the soot temperature and KL factor. Based on a series of systematic experiments, it is confirmed that O₂ concentration is the dominant factor affecting both the ignition delay and combustion period. The volumetric fraction of O₂ in ambient air has great effect on flame temperature and NOx emission, however ambient pressure has little effect on both values. On the contrary both of the volumetric fraction of O₂ in ambient air and the ambient pressure have large effect on soot production.