Patent ID: 6705547
Filing Date: 2004-03-16
Classification: B64D,F02K,Y02T

Abstract:
An active exhaust nozzle for a gas turbine engine comprisinga primary exhaust nozzle having a central axis and an exit end; the exit end having two sectors, a first noise reducing sector and a second noise transmission sector; the noise reducing sector being formed by a hinged section which allows a lip of the section, located at the exit end, to oscillate towards and away from the central axis; an active noise reduction means for actuating the hinged section of the first noise reducing sector to make the exhaust shear layer irregular and turbulent, thus scattering parts of the sound from sources inside the gas turbine engine and spreading the sound to a range of directions corresponding to the noise transmission sector, over a wide range of frequencies; and, a controller for actuating the active noise reduction means during operation when reduced noise is required in the direction defined by the noise reducing section.