Coupled simulation of internal flow and primary breakup for liquid sheet of pressure-swirl atomizer

In order to predict the injection characteristics more accurately and reveal the influence of atomizer structure on atomization process, the VOF multiphase flow model and large eddy simulation turbulent model were used to carry out the coupled CFD simulation of both internal flow and liquid sheet breakup process of the pressure-swirl atomizer of aeroengine. The clear air/liquid phase interface, instable wave of liquid sheet and primary breakup phenomenon were obtained. The simulation results show that with increasing the supplied fuel flow rate, the breakup pattern of liquid sheet undergoes a change from sinuous wave breakup and rim breakup to perforating breakup. And the change in breakup pattern is mainly due to the larger effect of circumferential disturbance caused by the atomizer structure on the breakup process of liquid sheet, which shortens the breakup length of liquid sheet. The numerically calculated spray cone angle and the breakup length of liquid sheet agree well with both measured values and calculated values by semi-empirical formulas.