Experimental Study of Effects of nozzle Hole Shape on Cavitating Flow

In this paper, the influence of nozzle hole shape on internal flow and near-nozzle spray behavior was studied.A flow visualization experimental system with a transparent scaled-up injector was setup.Three nozzles with the same hole outlet diameter but different hole shapes were used.Detailed comparisons of the cavitation and spray characteristics of the three nozzles were conducted under different fuel injection pressures.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.