The effect of cavitation on atomization in non-evaporating diesel sprays

The determination of the distribution of the local liquid volume fraction (LVF) in non-evaporating diesel sprays was achieved using Laser Induced Fluorescence (LIF). The LVF distribution developing during the primary and secondary atomisation was investigated as a function of rail pressure, physical properties and needle lift. Samples of conventional diesel and light kerosene were injected through an optically accessible mini-sac type injector, employing a custom diesel fuel injection system. The optical arrangement facilitated the acquisition of images with an image resolution of 28μm/pixel using a high speed camera operating at 10 kHz. The analysis is focused on images obtained at different injection stages (1.8ms, 3.7ms, 5.6ms after start of injection (SoI)). The results revealed that the diesel spray developed an asymmetric structure, especially at the intermediate and later stages of the injection. The LVF decreases with increasing axial distance and the primary atomisation occurs immediately after the spray enters the surrounding gas. Lastly, the findings of the phenomenological analysis suggests that conventional diesel shows a later primary and secondary atomisation than light kerosene, due to their difference in the physical properties