Experimental and Numerical Study on the Characteristics of Liquid Phase LPG and Diesel Fuel Sprays

This paper presents a comparison study on the spray characteristics with different fuels and different fuel injection parameters. Both experimental and numerical studies were employed in investigating the macroscopic spray structure and the spray characteristics of liquid-phase LPG or LPG/diesel blended fuel (LDBF) injection from high-pressure injectors. The experimental work was conducted on a high-pressure constant volume vessel with high-speed photography. Experimental results show that the spray tip penetration of LPG is shorter than that of the diesel fuel, and the spray cone angle of the LPG is also smaller than that of the diesel fuel at the same injection conditions because LPG has better evaporation and atomization. Based on the computation of characteristics of LPG and diesel fuel spray using KIVA-3V2 and KH-RT breakup model, it is found that the spray tip penetrations at the initial injection stage agree well between numerical and experimental results. There is a difference between predicted and experimental results at the late injection stage on account of the lower sensitivity of the high-speed photographic instrument. It is also found that the SMR of the LPG spray is smaller than that of the diesel fuel spray.