Experimental research on the effect of reflected shock waves on the evolution of a high-pressure diesel spray

Abstract

The shock wave has become a common phenomenon in modern diesel engines with the continuous increase in the fuel injection pressure. The shock wave reflects in the cylinder and affects the macroscopic structure of the spray and the mixing effect between the spray and surrounding air. In this study, the effects of the reflected shock wave on the evolution characteristics and the mixing characteristics of a high-pressure diesel spray were investigated using the Schlieren imaging method. The results show that the reflected shock wave significantly suppresses the development of the spray in the radial direction. However, the reflected shock wave has little effect on the development of the spray tip penetration. The volume and the average equivalence ratio of the spray under the reflected shock wave are also lower than those without the reflected shock wave. In addition, the evolution of the spray under different fuel injection angles was also analyzed. The results show that the different fuel injection angle affects the development of the spray width in the radial direction, which in turn has a significant influence on the spray cone angle.