Abstract：Based on the finite element liquid continuous phase turbulent flow simulation model, the internal oil flows of diesel engine equal diameter nozzle were studied. The effect of inlet pressure on the gas phase volume fraction, turbulent kinetic energy and symmetric axis linear velocity were analyzed. Results show that the pressure drop apparently occurs at the entrance of nozzle, the turbulence occurs at the entrance of nozzle and near the location of hole shows the biggest. The oil axial movement is inversely proportional to the speed and under pressure. The gas phase volume fraction has a monotone increasing trend with the increase of inlet pressure. When the inlet pressure increases to 120 MPa the gas phase volume fraction steadys at 100%. The location of the turbulent kinetic energy maximizes by the beginning of the nozzle entry central axis then gradually transfers to the nozzle inlet on the wall and the relationship between inlet pressure and flow rate has a linear change rule. Comprehensive analysis to determine the inlet pressure to guarantee in 100~120 MPa pressure type fuel atomization diameter nozzle efficiency is more beneficial.

Keywords: diesel engine; nozzle; flow characteristics; inlet pressure