Abstract: Single-element shear-coaxial GH₂/GO₂ injectors were simulated with non-chemical N-Sequations for cold flow conditions and chemical N-Sequations for combustion conditions.The chemical reaction was modeled with Arrhenius formulation.Detailed 9-step chemical dynamic model was used to describe the reaction of hydrogen and oxygen.The simulated results of typical cold flow fields and combustion fields were compared,showing that the mix ratio of combustion is much smaller than that of cold flow.The influences of velocity-ratio,recess-length and injector-flux for the cold flow condition are consistent with those for the combustion condition,while the influences of injection-velocity are contrary to each other.