Spray Characterization of High Pressure Gasoline Fuel Injectors with Swirl and Non-Swirl Nozzels 981935

Experimental results are reported on spray characterization of gasoline pintle injectors A and B; the former with swirl vanes while the latter without swirl vanes upstream the pintle seat. Injection system was common rail with accumulator unit injector and pressure fuel metering. Spray tip penetration length was measured by laser beam attenuation technique. Time-resolved droplet axial and radial velocity components and droplet diameter were measured at many probe positions in both axial and radial directions by a two-component phase Doppler particle analyzer (PDPA). The measurement covered detailed spray structures of both injectors under rail pressures ranged from 8 to 14 MPa and with fuel delivery from 11 to 42 mm³/inj for Injector A and from 4 to 28mm³/inj for Injector B. Correlations of droplet velocity and diameter with arrival time to the PDPA probe volume are discussed. Different conditional Sauter mean diameters (SMD) are determined in the time domain: SMD_e, a ensemble Sauter mean diameter as a function of arrival time; SMD_τ, a ensemble Sauter mean diameter as a function of time after start of injection; SMD_zj, a ensemble Sauter mean diameter as a function of axial. position for a given time after start of injection. For comparison, conventional mean (time independent) diameters and velocities are computed as functions of probe position. The present work helps in understanding of spray structures of gasoline injectors at different spray regions: leading edge, central body and tailing part. All experiments were conducted at ambient pressure and temperature.