An apparatus and method for injectors for use in combustion systems employing multiple non-solid or gas streams such as supercritical CO2 systems. The apparatus and method allow for reactants to be injected into a combustion chamber in such a way that combustion is locally inhibited. Injectors employing an inner and outer tube are designed to minimize mixing between the non-solid gas streams and allow for swirling and stratification of the non-solid or gas streams.