Turbofan engine with reduced noise

A noise-reduced turbofan engine comprising:

• a) a core engine having axial flow fans, multistage compressors and multistage reaction turbines, and a thrust of at least about 18,000 lbs at sea level, the fans being at an upstream end of the core engine for generating axial fan air flow;
• b) bypass ducts for receiving at least portion of the axial fan air flow from the fans, the ducts terminating at a common nozzle located at the outlet for exhaust gas from the engine, the common nozzle having a mixing plane area for each of the fan air flow and for the exhaust gas in a range between 700 and 800 square inches;
• c) a mixer in the common nozzle disposed axially to receive and exhaust the exhaust gas and fan air, said mixer having an upstream end and an annular mixer wall axially extending downstream therefrom, the wall being formed into a plurality of circumferentially alternating radially inward and radially outward lobes, the radially inward lobes defining cold chutes for radially inwardly diverting fan air and outward lobes defining hot chutes for permitting radially outward expansion of exhaust gas;
• and
• d) a thrust reverser movable into a first position for converting axial flow of exhaust gas and fan air from the tail pipe assembly into reverse thrust, or into a second stowed position wherein reverser doors act as aerodynamic fairings for the nacelle afterbody.

A noise reduced turbofan engine comprising:

• a) a core engine having axial flow fans, multistage compressors and multistage reaction turbines, and a thrust of at least about 18,000 lbs at sea level, the fans being at an upstream end of the core engine for generating axial fan air flow;
• b) bypass ducts for receiving at least portion of the axial fan air flow from the fans, the ducts terminating at a common nozzle located at the outlet for exhaust gas from the engine, the common nozzle having a mixing plane area for each of the fan air flow and for the exhaust gas in a range between 700 and 800 square inches;
• c) a mixer in the common nozzle disposed axially to receive and exhaust the exhaust gas and fan air, said mixer having an upstream end and an annular mixer wall axially extending downstream therefrom, the wall being formed into a plurality of circumferentially alternating radially inward and radially outward lobes, the radially inward lobes defining cold chutes for radially inwardly diverting fan air and outward lobes defining hot chutes for permitting radially outward expansion of exhaust gas;
• d) a thrust reverser movable into a first position for converting axial flow of exhaust gas and fan air from the tail pipe assembly into reverse thrust, or into a second stowed position wherein reverser doors act as aerodynamic fairings for a nacelle afterbody;
• e) a bleed air valve selectively operational to bleed air from the core engine when the valve is open, and a duct for directing bleed air to the common nozzle.