The presence of cavitation and turbulence in a diesel injector nozzle has significant effects on the subsequent spray characteristics.In this paper,the influence of nozzle hole shape on internal flow and near-nozzle spray behavior at stationary conditions was studied.A flow visualization experimental system with a transparent scaled-up injector nozzles was setup.Three min-sac nozzles with the same hole outlet diameter but different hole shapes(cylindrical,convergent and divergent)were used for the investigations.Detailed comparisons of the cavitation and spray characteristics of the three nozzles were conducted under a variety of fuel injection parameters.Results show that cavitation collapsed inside the hole lead to an increment of flow turbulence but have limited effects on spray cone angle.However,when cavitation extends to the hole outlet,the spray cone angle increased sharply.Furthermore,the hydraulic flip phenomenon which causes a spray abnormality and flow rate discontinuity was also investigated.