Gas turbine exhaust nozzle for controlled temperature flow across

Abstract

An exhaust nozzle for exhausting the effluent of a turbofan gas turbine engine across a portion of the upper surface of an aircraft wing wherein the exhaust nozzle is arranged to establish a temperature profile within the exhausted gases that prevents overheating the wing surface. The nozzle includes a contoured outer housing that longitudinally transists from a circular entrance opening, arranged for interconnection with the rear face of a gas turbine engine, to a semi-elliptical outlet opening located on the upper surface of the aircraft wing. A generally tubular mixer section, of the daisy type, is mounted within the outer housing and coaxially surrounds an engine tail plug. Exhaust gases flowing from the engine fan stage flow through an annular flow duct formed between the inner surface of the forward portion of the outer housing and the outer surface of the mixer section and the high temperature gases flowing from the engine turbine stages flow through an annular duct formed between the tail plug and the inner surface of the mixer section. As the turbine exhaust gases and the fan air flow past the mixer section exit plane, the two fluid streams mix with one another to increase engine thrust and decrease engine noise level. To establish a temperature profile in which the exhaust gases flowing along the aircraft wing do not overheat the wing structure, the outer housing is contoured to have a generally elliptical cross-sectional geometry at the exit plane of the mixer section and the mixer section lobes are of unequal radial dimension such that the mixer section has an asymmetric cross-sectional shape.