Numerical simulations of liquid film primary breakup in a pintle injector: a parametric study

In the present study, numerical simulations have been conducted to investigate the primary breakup of the liquid film in the gas-liquid pintle injector, using the volume of fluid (VOF) method with the adaptive mesh refinement to capture the gas-liquid interface. The film breakup and atomization characteristics in the pintle injector are studied by changing the structure parameters and the momentum ratio. The results show that increasing the radial liquid flow rate to raise the momentum ratio promotes the atomization performance while decreasing the axial gas flow rate deteriorates the atomization performance. The two methods of altering the momentum ratio both cause the spray angle to increase with the momentum ratio, but the first routine leads to a slower increase. With the increase of opening distance, the velocity of the liquid flow decreases, and the thickness of the liquid film increases significantly, making the film hard to break up. The skip distance negatively influences the film breakup and atomization when the skip distance exceeds one. Moreover, the hollow region of the spray is decreased with a longer skip distance, which is detrimental to fuel combustion.