General Electric Company

The United States of America As Represented by the United States

Donald Patrick McHugh

John W Vdoviak

Rollin G Giffin, Iii

Ivan Elmer Woltmann

Tom Foster

Donald W Speir

Ralph Harold Brown

Donald F Cook

Dan Joseph Rundell

An afterburning, gas turbine aircraft engine with an annular duct for carrying bypass airflow is provided with a sliding valve type of rear Variable Area Bypass Injector (VABI) system. This rear VABI varies the direction and volume of the flow of bypass air into separate regions at an afterburning section of the engine. The system includes a sliding valve mounted in the bypass duct that is translated axially to open and close slots leading to core engine exhaust flow in the afterburning section. The unique structure of the injector system enables the axial translation of this sliding valve to simultaneously control bypass airflow into: first, a mixer just upstream of the afterburning section; second, a plurality of slots leading to the afterburning section; and third, an exhaust nozzle cooling liner that is cooled with the remaining portion of the bypass air. The system is actuated with a mechanical design that uses both rotation and translation to simplify the actuation motion so that one actuator can translate the valve. Because the system employs a valve that translates over a plurality of slots, it is commonly referred to as a variable slot bypass injector.

Variable slot bypass injector system

A plurality of circumferentially displaced hollow members are positioned between an outer bypass duct and the center body of the core engine. Each of the hollow members is open at the radially outward end thereof for receiving relatively cool gas from the bypass duct. Each hollow member is formed with an opening in the side thereof extending substantially the full length of the hollow member near the trailing edge thereof for discharging bypass gas from the bypass duct in a direction facilitating thorough mixing of the bypass gas and core gases. A pivoted vane is provided in this opening of each of the hollow members and these vanes are controlled to vary the airflow through the aforementioned openings. Radially extending spraybars or fuel rods are provided within each hollow member adjacent opposite sides thereof so as to be cooled by the bypass air flowing through the hollow member. The spraybars are provided with a plurality of openings adjacent the sidewalls of the hollow members and corresponding openings are provided in these walls so that fuel, during augmentor operation, is directed into the area between adjacent hollow members. The aft end of each hollow member is formed as a relatively wide flat surface which acts as a flameholder for the fuel supplied from the spraybars and burned in the augmentor. The forward end of each hollow member is curved to an angle corresponding generally to the swirl angle of core gases exhausted from the core engine so as to effect a deswirling of this gas.

Gas turbine engine with augmentor and variable area bypass injector

A design technique, method and apparatus for controlling the bypass gas stream pressure and varying the bypass ratio of a mixed flow gas turbine engine in order to achieve improved performance. The disclosed preferred embodiments each include a unique mixing device for combining the core and bypass gas streams which includes means for varying the area at which the bypass stream is injected into the core stream. The variable area mixing device permits the static pressures of the core and bypass streams to be balanced prior to mixing at widely varying bypass stream dynamic pressure levels. The ability to balance the core and bypass stream static pressures at widely varying bypass stream dynamic pressures permits the mixed flow gas turbine engine of this invention to operate efficiently over a wide range of bypass ratios and further permits the dynamic pressure of the bypass stream to be maintained at a level which will keep the engine inlet airflow matched to an optimum design level throughout a wide range of engine thrust settings. To further assist in maintaining a static pressure balance between the core and bypass streams prior to mixing, the variable area mixing device may be provided with means to accelerate the bypass stream to supersonic velocities immediately prior to mixing combined with means to control the degree of expansion of the bypass stream after it has been accelerated to supersonic and before it is mixed with the core stream. To increase the flexibility in adjusting the dynamic pressure of the bypass stream and provide the potential for a relatively high thrust level without the use of an afterburner, the system may be modified by the use of a split fan section in conjunction with two concentric bypass ducts.

Variable mixer propulsion cycle

A gas turbine engine actuation system for simultaneously controlling the flow areas defined by two generally coannular ducts, each duct terminating in a nozzle of the variable flap variety. A bell crank pivotable about an axis on the outer (secondary) nozzle is link-connected to the inner (primary) nozzle and also to a translatable actuation ring. The geometry of the flaps, link and bell crank is such that when the secondary nozzle is positioned by the ring and bell crank, the movement thereof is transferred to the primary nozzle to modulate the throat areas defined thereby. Where the secondary (supersonic) nozzle is of the divergent variety extending downstream of the primary nozzle so as to provide a common expansion surface and exit area, a link connection between one of the secondary nozzle flaps and the actuation ring causes simultaneous exit area and throat area modulation in a predetermined relationship. A method is provided for actuating the nozzles between the augmented and unaugmented thrust operating modes.

Actuation system for a gas turbine engine exhaust device

A propulsion nozzle having a substantially axial nozzle shroud and an articulated plug mounted in spacial relation therewith to form a motive fluid flow path having a throat therebetween. The plug is articulative to permit the throat of the nozzle to be disposed, as required, in a position at the downstream end of the shroud or at a position upstream of the downstream end without translating either the shroud or the plug.

Growing community of inventors

Cincinnati, OH, United States of America

Donald Patrick McHugh