Abstract: In the arbitrary curvilinear coordinates,three-dimensional two-phase reaction flow fields in the rectangular combustor with double axial swirler and the reverse-flow annular combustor with swirl cup were numerically investigated.Renormalization group(RNG) k-ε,second order moment-eddy break up model(SOM-EBU) and six-flux model were used to consider the influences of turbulence viscosity,reaction rate and radiative heat transfer,respectively.Semi-implicit method for pressure linked equation(SIMPLE) algorithm was used to solve the flow field,and particle source in cell method was adopted to consider the coupling between gas-phase and liquid-phase.The fuel steady stepwise method was proposed to predict the lean blowouts of combustors.Predictions are in agreement with corresponding experimental data,showing that this method for predicting lean blowout is reliable and can be used for engineering applications.