Patent ID: 7631499

Claim:
An axially staged combustion system for a gas turbine engine comprising: a main body structure having a plurality of first injectors and a plurality of second injectors, compressed air being provided to said first injectors; first structure to provide fuel to each of said first injectors, said fuel provided to said first injectors being adapted to mix with the compressed air provided to said first injectors and ignite to produce a flame such that the flame associated with said first injectors defines a flame front that is axially spaced from a reference surface of said main body structure; each of said second injectors comprising a section extending from said reference surface of said main body structure and positioned such that fuel or a combination of air and fuel exits said second injectors axially downstream from a first axial location where a mixture of compressed air and fuel exits said first injectors, wherein the first axial location is at the reference surface; second structure to provide fuel to each of said second injectors, said fuel passing through said second injectors and exiting each of said second injectors at a second axial location downstream of the first axial location such that said fuel exiting each of said second injectors mixes with air and ignites at a third axial location downstream of the second axial location, wherein said fuel from each of said second injectors is ignited in a common flame chamber defined in said main body structure; wherein said second structure provides fuel to said second injectors at a positive rate such that said fuel mixes with air to create a fuel and air mixture richer than a fuel and air mixture resulting from a positive rate at which fuel is provided to said first injectors by said first structure; and wherein said main body structure comprises a main body unit having a plurality of first passages defining said first injectors and a plurality of second passages, an outer surface of said main body unit defining said reference surface of said main body structure, and a plurality of tubes associated with said second passages, corresponding sets of said tubes and said second passages defining said second injectors.