Detailed experimental and numerical investigation of the spray structure in a GDI high-pressure swirl injector

Results provided detailed information on the spatial velocity distribution and size of droplets close to the nozzle region. Ensemble averaged velocity field of fuel droplets obtained on the vertical plane through the injector axis showed high velocity values up to 100 m/s in the early stage of injection, whereas during the transition to completely developed main spray, droplets travel at lower velocities. The velocity field obtained on the cross section of the spray, at locations close to the nozzle (5 and 10 mm) and in the early stage of injection (up to 0.6 ms), showed a symmetric radial velocity field around the spray axis. Size measurements performed near the nozzle showed a D10 profile constant along the stationary period of injection and not affected by the injection pressure.