A gas turbine engine system includes a compressor, a combustor, and a turbine. The combustor is coupled to the compressor and disposed downstream of the compressor. The combustor includes a secondary combustor section coupled to a primary combustor section and disposed downstream of the primary combustor section. The combustor also includes a transition nozzle coupled to the secondary combustor section and disposed downstream of the secondary combustor section. The combustor further includes an injector coupled to the secondary combustor section, for injecting an air-fuel mixture to the secondary combustor section. The turbine is coupled to the combustor and disposed downstream of the transition nozzle; wherein the transition nozzle is oriented substantially tangential to the turbine.