SECONDARY NOZZLE FOR JET ENGINE

摘要

A third stream duct producing a third air stream at reduced pressure that is exhausted through a separate nozzle that is concentric with the main or primary engine nozzle. The third stream exhaust air from the separate concentric nozzle is exhausted to a location at which pressure is ambient or sub-ambient. The location at which the third stream air is exhausted contributes to the thrust of the aircraft. The airstream from the third air duct is exhausted through an exhaust nozzle of the third duct that is positioned at the interface between the aft of the airframe and the leading edge of the engine outer flaps. This location is a low pressure region that has a recirculation zone. The exhaust of third stream air to this low pressure region substantially reduces or eliminates this recirculation zone and associated boat tail drag, thereby improving the efficiency of the engine.

主权项

1. An aircraft turbofan engine having a fan portion providing three streams of air flow to the engine, comprising:
a primary nozzle, wherein combustion fluid is exhausted after core air flow from the fan portion is combined with fuel and combusted to form the combustion fluid, the nozzle including a plurality of outer flaps and seals; a bypass duct wherein bypass air flow is exhausted through the primary nozzle; and a third duct, wherein third stream air flow is exhausted through a secondary nozzle that is concentric with the primary nozzle, the secondary nozzle exhausting the third stream air to a location having a pressure that is lower than a pressure of the third stream air in the secondary nozzle.