Study of the soot quantification for two-stage injection of hydrogenated catalytic biodiesel in a constant-volume combustion chamber

Abstract

[EN] The effect of two-stage injection strategies on the soot formation of 0# fossil diesel were investigated experimentally using a constant volume combustion chamber. The ambient conditions was kept constant as injection pressure 150 MPa, ambient gas temperature 900 K, ambient gas pressure 45 bar. A high-speed diffused back-illumination extinction imaging technique was employed to make quantitative measurement on temporal soot evolution and reacting spray liquid length and a direct high-speed camera was used to measure the ignition delay. Two-stage injection strategies were varied with different pilot and main injection time, including a sweep of dwell time in pilotmain injection and pilot injection duration. The results show that the ignition delay decreases with the increasing dwell time. It may result from the entrained surrounding gas enhance the spray combustion process. In the reacting condition, the liquid-phase penetration is slightly longer with the shorter dwell time. However, the pilot injection duration shows slighter impact. The longer dwell time contributes to more total soot mass while the different pilot injection duration barely affect the total soot mass of the main injection.