Three stream, variable area fixed aperture nozzle with pneumatic actuation

A variable internal exhaust area nozzle for a gas turbine engine, comprising:

• a plurality of flap trains extending around a periphery of the gas turbine engine, with each flap train including a convergent flap pivotally attached to an engine body and a divergent flap pivotally attached to the engine body downstream of the convergent flap;
• a fluid circuit in communication with the convergent and divergent flaps and configured to pivot the convergent and divergent flaps between a radially inward position and a radially outward position;
• and
• a plurality of side walls that separate the plurality of flap trains adjacent to each other in a circumferential direction, the plurality of side walls extending from one axial end of the nozzle to at least a region between the convergent flap and the divergent flap;
• wherein the nozzle is configured to provide a fixed exit aperture.

A variable internal exhaust area nozzle for a gas turbine engine, comprising:

• a plurality of flap trains extending around a periphery of the gas turbine engine, with each flap train including a convergent flap pivotally attached to an engine body and a divergent flap pivotally attached to the engine body downstream of the convergent flap;
• and
• a fluid circuit in communication with the convergent and divergent flaps and configured to pivot the convergent and divergent flaps between a radially inward position and a radially outward position;
• wherein the convergent flap has a closing pressure chamber selectively communicating with a closing portion of the fluid circuit, and the convergent flap is configured to move radially outward in response to the closing pressure chamber receiving a working fluid from the closing portion of the fluid circuit;
• wherein the divergent flap has a closing pressure chamber selectively communicating with a closing portion of the fluid circuit, and the divergent flap is configured to move radially outward in response to the closing pressure chamber receiving a working fluid from the closing portion of the fluid circuit;
• wherein the nozzle defines a throat configured to pass a primary stream;
• wherein the nozzle further defines a series of variable area passages spaced apart from each other along a periphery of the throat;
• wherein the nozzle further defines a series of fixed area passages spaced apart from each other along the periphery of the throat, such that the nozzle is configured to bifurcate a third stream flow;
• and
• wherein the fluid circuit is one of a pneumatic circuit and a hydraulic circuit.