This paper presents some results on the numerical simulation of the two-phase flow in a dump combustor, under realistic conditions. This study has been performed with a two-phase flow code, which simulates the main physical phenomena occurring in a ramjet combustion chamber. Those models were validated on basic configurations. Interactions between the gas and liquid phases, called two-way coupling, are particularly studied in this paper. Two methods have been used to include two-way coupling in the simulations. First one is based on a global iterative scheme, the second one on an unsteady approach. The results obtained by the two methods are in a quite good agreement. The discrepancy appearing in the flow fields may be created by the aerodynamic flow field calculation, which may be erroneous in the outlet nozzle, due to problems to get the the exit nozzle flow chocked. However, the significant interactions between the two phases, particularly near the walls, induce great computation times for the first method. Both methods will be used on other configurations, and a combustion model will be added to the numerical code, in order to compute combustion efficiency in such configurations.