Effect of Injection Pressure on Droplet Behavior Inside Diesel Fuel Sprays

Measurements of temporal and spatial changes in the velocity and size of droplets of diesel fuel sprays under two injection pressures were conducted near the nozzle orifice by a laser 2-focus velocimeter (L2F). The result showed that the size of droplets under higher rail pressure was larger than that under lower rail pressure at the spray center and was smaller than that under lower rail pressure at the spray periphery. It was found that the size of droplets deceased in the downstream direction of the spray and the decrease rate increased with the rail pressure. The cross-sectional average velocity increased and the cross-sectional average size decreased with the rail pressure in the spray near the nozzle exit.