A method and system of effervescent atomization of liquid fuel for a rotating detonation combustor (RDC) for a propulsion system is provided. The method includes flowing liquid fuel through a fuel injection port of a nozzle assembly of the RDC system; flowing a gas through the fuel injection port of the nozzle assembly volumetrically proportional to the liquid fuel; producing a gas-liquid fuel mixture at the fuel injection port by mixing the flow of gas and the flow of liquid fuel; flowing an oxidizer through a nozzle flowpath of the RDC system; producing an oxidizer-gas-liquid fuel mixture by mixing the gas-liquid fuel mixture and the flow of oxidizer within the nozzle flowpath; and igniting the oxidizer-gas-liquid fuel mixture within a combustion chamber of the RDC system.