A system, comprising: a gas turbine combustor configured to combust a fuel and an oxidant and comprising a combustor casing; the system further comprising an aerodynamic peg, and a manifold, wherein, housed within the manifold, provided are a first fluid manifold and a second fluid manifold, the aerodynamic peg being disposed in the gas turbine combustor and comprising an airfoil-shaped cross section, wherein the aerodynamic peg comprises exactly two passages (114, 116), namely a first passage configured to convey a first fluid into the gas turbine combustor and a second passage configured to convey a second fluid into the gas turbine combustor, wherein the first passage connects the first fluid manifold to first fluid orifices, so as to convey the first fluid into the gas turbine combustor and the second passage connects the second fluid manifold to second fluid orifices so as to convey the second fluid into the gas turbine combustor, wherein the first and second fluids are different from one another, wherein the first fluid comprises a non-oxidant and non-fuel fluid and the second fluid comprises fuel, wherein the first fluid orifices and second fluid orifices open out onto an outer surface of the aerodynamic peg, and wherein the first passage is disposed upstream of the second passage relative to a direction of airflow flowing past the aerodynamic peg, and the first fluid orifices open out onto the surface of the aerodynamic peg upstream of the second fluid orifices relative to a direction of airflow flowing past the aerodynamic peg, such that the first fluid conveyed by the first fluid orifices creates a non-combustible shield to protect components upstream of the second fluid conveyed by the second fluid orifices, and wherein the aerodynamic peg is disposed in a casing location of the gas turbine combustor or in a fuel nozzle location of the gas turbine combustor. a gas turbine combustor configured to combust a fuel and an oxidant and comprising a combustor casing; the system further comprising an aerodynamic peg, and a manifold, wherein, housed within the manifold, provided are a first fluid manifold and a second fluid manifold, the aerodynamic peg being disposed in the gas turbine combustor and comprising an airfoil-shaped cross section, wherein the aerodynamic peg comprises exactly two passages (114, 116), namely a first passage configured to convey a first fluid into the gas turbine combustor and a second passage configured to convey a second fluid into the gas turbine combustor, wherein the first passage connects the first fluid manifold to first fluid orifices, so as to convey the first fluid into the gas turbine combustor and the second passage connects the second fluid manifold to second fluid orifices so as to convey the second fluid into the gas turbine combustor, wherein the first and second fluids are different from one another, wherein the first fluid comprises a non-oxidant and non-fuel fluid and the second fluid comprises fuel, wherein the first fluid orifices and second fluid orifices open out onto an outer surface of the aerodynamic peg, and wherein the first passage is disposed upstream of the second passage relative to a direction of airflow flowing past the aerodynamic peg, and the first fluid orifices open out onto the surface of the aerodynamic peg upstream of the second fluid orifices relative to a direction of airflow flowing past the aerodynamic peg, such that the first fluid conveyed by the first fluid orifices creates a non-combustible shield to protect components upstream of the second fluid conveyed by the second fluid orifices, and wherein the aerodynamic peg is disposed in a casing location of the gas turbine combustor or in a fuel nozzle location of the gas turbine combustor.