Chamber geometry effect on non-evaporating diesel spray evolution

The effect of spray chamber geometry on the penetration and spreading angle of common rail non-reacting diesel sprays at room temperature condition in a constant volume chamber has been investigated. The high pressure cylindrical chamber used has dimensions similar to those used in the literature. Spray chamber internal geometry was modified to yield five different chamber height-to-diameter ratios and two different nozzle stand-off distances. Sprays from a sing-hole nozzle were examined for an injection pressure of 1000bar into a chamber pressure of 50bar, which closely resemble the operating conditions in a number of real engines. A volume illumination method was used to characterise the spray structure that covers tip penetration, tip speed and spray spread angle. For pressure conditions used, little sensitivity to vessel geometry was found for variation in height to diameter ratio from 0.6 to 5.1 and variation in nozzle stand-off distance from 2mm to 54mm. While the spray spread angle was found to be very sensitive to the image intensity threshold value, the spray tip penetration remained very stable over the range of intensity threshold values investigated.