G0700506 Study on Characteristics of a Diesel Spray under Small-Quantity Injection Condition

Abstract

This study aims to investigate the spray development process of diesel spray under small-quantity injection condition. The effects of injection pressure and injection quantity on spray tip penetrations were analyzed using a rapid compression and expansion machine, and the effects of injection-rate pattern on spray development process were simulated using a one-dimensional spray model. The results show that the spray tip penetration is dependent on time with exponent more than one just after injection start, and the exponent turns to one and one half as time elapses. With small-quantity spray the exponent is one forth after the end of injection. The simulation results show that the penetration dependence on time to the power of more than one during beginning of injection is caused by increasing momentum flux by rising injection rate, and the penetration rapidly decelerates as reducing momentum flux at the spray tip by decline of injection rate.