G070012 Effect of Ambient Gas Density on Entrainment / Capturing Processes of Ambient Gas into Diesel Spray

Abstract

An experimental study was made of the characteristics of ambient gas entrainment into a non-evaporating fuel spray injected by a Diesel common rail injection system into a high-pressure constant volume vessel. The gas flow field around the spray was measured using a particle image velocitmetry coupled with a laser induced fluorescence (LIF-PIV) technique. The mass flow rate of the ambinet gas into the spray through the spray boundary was calculated by using the ambient gas velocity data. The spray-ambient gas interactions along the spray boundary were categorized into three sections, that is, (1) the entraiment section from nozzle exit to the middle of the spray, (2) the capturing section at the spray tip, and (3) the recirculation section between (1) and (2) where relatively large-scale vortexes appear along the spray boundary. The ambient gas flow rate into the spray through the section (2) is more dominant rether than that through the section (1). The total flow rate of the ambient gas into the spray increases as the ambient gas density increases.