Abstract: A bleed valve that expels a gas from a compressed region includes a valve section and a muffler section coupled to and located downstream from the valve section. The valve section includes a centerbody and a housing. The centerbody supports a plunger that controls opening and closing of the bleed valve. The centerbody is coupled to the housing by at least one strut disposed substantially radially. The at least one strut may have a cross-section that reduces or suppresses flow separation and vortex shedding from the at least one strut. The muffler section may include a baffle plate and a dome plate. A honeycomb may be installed between the baffle plate and the dome plate. The bleed valve may also include a middle plate on a face of the honeycomb and a conical diverter immediately upstream from the baffle plate. Other embodiments are also described.

Abstract: An embodiment of the invention is a technique to suppress noise in a jet engine. A substantially annular fan nozzle of a separate-flow turbofan engine includes a flow boundary surface and an outlet to discharge fan air into atmosphere. At least one vane extends substantially radially from the flow boundary surface to vector at least a portion of the fan air toward a direction where noise suppression is desired. The-vane is situated in proximity of the outlet and has a span substantially greater than a thickness of a local boundary layer of the fan air.

Abstract: A bleed valve that expels a gas from a compressed region includes a valve section and a muffler section coupled to and located downstream from the valve section. The valve section includes a centerbody and a housing. The centerbody supports a plunger that controls opening and closing of the bleed valve. The centerbody is coupled to the housing by at least one strut disposed substantially radially. The at least one strut may have a cross-section that reduces or suppresses flow separation and vortex shedding from the at least one strut. The muffler section may include a baffle plate and a dome plate. A honeycomb may be installed between the baffle plate and the dome plate. The bleed valve may also include a middle plate on a face of the honeycomb and a conical diverter immediately upstream from the baffle plate. Other embodiments are also described.

Abstract: An embodiment of the invention is a technique to suppress noise in a jet engine. A substantially annular fan nozzle of a separate-flow turbofan engine includes a flow boundary surface and an outlet to discharge fan air into atmosphere. At least one vane extends substantially radially from the flow boundary surface to vector at least a portion of the fan air toward a direction where noise suppression is desired. The-vane is situated in proximity of the outlet and has a span substantially greater than a thickness of a local boundary layer of the fan air.

Abstract: An embodiment of the invention is a technique to suppress noise in a jet engine. A substantially annular fan nozzle is attached to a pylon and discharges a fan stream into atmosphere from an aft end thereof. A core nozzle discharges core stream into the atmosphere. The core nozzle has an exterior surface. A stream director is mounted on the pylon to direct the fan stream away from the pylon. At least a portion of the stream director is situated outside the aft end to maintain substantially constant flow area of the fan nozzle.

Abstract: An embodiment of the invention is a technique to suppress noise in a jet engine. A noise suppressor includes an exhaust duct to exhaust a first stream from an air stream taken from an inlet. The exhaust duct has an exit end. The air stream is divided into the first stream and a second stream. The second stream has an axis. A stream director attached to vicinity of the exit end directs the first stream to a direction that is away from or sideward relative to the axis.

Abstract: An embodiment of the invention is a technique to suppress noise in a jet engine. A noise suppressor includes an exhaust duct to exhaust a first stream from an air stream taken from an inlet. The exhaust duct has an exit end. The air stream is divided into the first stream and a second stream. The second stream has an axis. A stream director attached to vicinity of the exit end directs the first stream to a direction that is away from or sideward relative to the axis.

Abstract: An embodiment of the invention is a technique to suppress noise in a jet engine. A noise suppressor includes an exhaust duct to exhaust a first stream from an air stream taken from an inlet. The exhaust duct has an exit end. The air stream is divided into the first stream and a second stream. The second stream has an axis. A stream director attached to vicinity of the exit end directs the first stream to a direction that is away from or sideward relative to the axis.

Abstract: An embodiment of the invention is a technique to suppress noise in a jet engine. A substantially annular fan nozzle is attached to a pylon and discharges a fan stream into atmosphere from an aft end thereof. A core nozzle discharges core stream into the atmosphere. The core nozzle has an exterior surface. A stream director is mounted on the pylon to direct the fan stream away from the pylon. At least a portion of the stream director is situated outside the aft end to maintain substantially constant flow area of the fan nozzle.

Abstract: An embodiment of the invention is a technique to suppress noise in a jet engine. A noise suppressor includes an exhaust duct to exhaust a first stream from an air stream taken from an inlet. The exhaust duct has an exit end. The air stream is divided into the first stream and a second stream. The second stream has an axis. A stream director attached to vicinity of the exit end directs the first stream to a direction that is away from or sideward relative to the axis.

Abstract: A method and an apparatus for enhancing fluid mixing. The method comprises the following: (a) configuring a duct to have an effective outer wall, an effective inner wall, a cross-sectional shape, a first cross-sectional area and an exit area, the first cross-sectional area and the exit area being different in size; (b) generating a first flow at the first cross-sectional area, the first flow having a total pressure and a speed equal to or greater than a local speed of sound; and (c) generating a positive streamwise pressure gradient in a second flow in proximity of the exit area. The second flow results from the first flow. Fluid mixing is enhanced downstream from the duct exit area.

Abstract: A method and an apparatus for enhancing fluid mixing. The method comprises the following: (a) configuring a duct to have an effective outer wall, an effective inner wall, a cross-sectional shape, a first cross-sectional area and an exit area, the first cross-sectional area and the exit area being different in size; (b) generating a first flow at the first cross-sectional area, the first flow having a total pressure and a speed equal to or greater than a local speed of sound; and (c) generating a positive streamwise pressure gradient in a second flow in proximity of the exit area. The second flow results from the first flow. Fluid mixing is enhanced downstream from the duct exit area.

Abstract: A method and device for reducing the amount of noise generated by a supersonic jet engine is provided. The method creates an envelope of air around the supersonic jet exhaust. The temperature and velocity of this envelope is controlled to eliminate or reduce the formation of noise making Mach waves.

Abstract: A method and device for reducing the amount of noise generated by a supersonic jet engine is provided. The method creates an envelope of air around the supersonic jet exhaust. The temperature and velocity of this envelope is controlled to eliminate or reduce the formation of noise making Mach waves.

Abstract: A method and device for reducing the amount of noise generated by a supersonic jet engine is provided. The method creates an envelope of air around the supersonic jet exhaust. The temperature and velocity of this envelope is controlled to eliminate or reduce the formation of noise making Mach waves.