Near-Field Velocity Measurement of a Multihole GDI Injector

This work focuses on the experimental measurements of the spray velocity in the near-nozzle field of a commercial GDI injector at two injection pressures: 5 MPa and 10 MPa. Two regions were investigated by means of backlight imaging technique: the jet periphery (dilute region) within 10 orifice diameter; and dense region within 30 orifice diameter. Two cross-correlation algorithms were used: an in-house algorithm, applied to the dilute region, while a standard PIV algorithm was applied to the dense region. It yields that with a careful setting of the parameters, both algorithms were highly precise: less than 1.2% error in the dilute region and 3% in the dense region. Moreover, the consisten…