Abstract
This study was performed to clarify the mechanism of diesel fuel spray formation with the greatly magnified photographs and auto-correlation PIV technique by laser-light sheet method of pulsed ruby laser. From the magnified photographs taken at near the nozzle hole exit region, it was found that injected fuel under high ambient pressure condition was broken-up at peripheral area of spray. With PIV technique, local fuel spray particle motion was analyzed and velocity vector and vorticity of the fuel spray were obtained. The vortex number increased and vorticity scale became smaller and its value grew higher with the increase of fuel injection velocity. The mixing of fuel spray in ambient gas seems to be promoted and the turbulence is expected getting higher in those regions.
