Interface-tracking method volume of fluid (VOF) was used to simulate the flow process in pressure-swirl injector.The process of liquid phase filling injector was exhibited:pucker appears at first

then distinguishes with the increase of liquid.Velocity and pressure distribution were especially analyzed in different sections of injector.As both liquid and gas phase coexist in the injector

the flow field is highly complex.Total pressure loss lies mostly in the convergent and columned sections

so increasing convergent angle helps to reduce total pressure loss.Setting a divergent angle at injector exit can increase liquid phase velocity and reducing liquid sheet thickness can get better atomization finally.