초록 ▼

A double bypass, variable cycle gas turbofan engine is provided with a variable area bypass injector which varies the area through which the inner bypass stream is injected into the outer bypass stream. The bypass injector comprises an upstream variable area, double bypass selector valve, the positi

A double bypass, variable cycle gas turbofan engine is provided with a variable area bypass injector which varies the area through which the inner bypass stream is injected into the outer bypass stream. The bypass injector comprises an upstream variable area, double bypass selector valve, the position of which determines whether the engine will operate in the single or double bypass mode, and a downstream static pressure valve which defines an optimum flow path for injecting the inner bypass stream into the outer bypass stream. The ability to vary the area through which the inner bypass stream is injected into the outer bypass stream permits the static pressure valve to operate as an ejector and permits control of the two bypass air streams through creation of a static pressure balance at the exit of the variable area bypass injector. The ability to control the bypass operating mode and the static pressure balance at the confluence of the two bypass streams eliminates the necessity for one exhaust duct and one exhaust nozzle, thereby reducing complexity and weight, and improves the engine-aircraft integration by reducing engine and nozzle diameters.

대표청구항 ▼

An improved gas turbofan engine of the type having a core engine, a front fan section for pressurizing a flow of air, an outer bypass duct for bypassing a stream of pressurized air around the core engine, an aft fan section for further pressurizing the air discharged from the front fan section and a

An improved gas turbofan engine of the type having a core engine, a front fan section for pressurizing a flow of air, an outer bypass duct for bypassing a stream of pressurized air around the core engine, an aft fan section for further pressurizing the air discharged from the front fan section and an inner bypass duct for bypassing an airstream from the aft fan section into the outer bypass duct and around the core engine, wherein the improvement comprises: a common bypass duct for receiving confluent streams from the inner and outer bypass ducts and bypassing the confluent flow around the core engine; and a variable area bypass injector for selectively modulating and separating the airstreams through the inner and outer bypass ducts including static pressure valve means for varying the area through which the inner bypass duct airstream is injected into the common bypass duct at the point of confluence of the inner and outer bypass ducts, and a bypass selector valve associated with the outer bypass duct and which is operable between two positions, one at which flow through the outer bypass duct is prohibited and another at which flow through the outer bypass duct is permitted.