Exhaust assembly for a high speed civil transport aircraft engine

An exhaust assembly for an aircraft gas turbine engine including a core engine having an outlet for discharging exhaust gases comprising:

• a casing having an inlet for receiving said exhaust gases from said core engine outlet;
• a variable area converging-diverging CD nozzle attached to said casing and including a first throat having a flow area A.sub.8 and an outlet having a flow area A.sub.9 for channeling said exhaust gases said CD nozzle further including:
• a plurality of spaced apart primary flaps defining therebetween a converging channel, each of said primary flaps having a downstream end, and an upstream and pivotally connected to said casing;
• a plurality of spaced apart secondary flaps defining therebetween a diverging channel, each of said secondary flaps having an upstream end pivotally connected to a respective one of said primary flap donwstream ends to define said first throat, and a downstream end pivotally and slidably connected to said casing, said diverging channel extending downstream from said first throat to said nozzle outlet;
• a plurality of spaced apart retractable chutes disposed upstream of said nozzle outlet in a flowpath surface and positionable in a deployed position inclined in a downstream direction radially away from said flowpath surface for forming a converging nozzle in fluid communication with said casing inlet including a second throat having a flow area A.sub.8 " less than said first throat area A.sub.8, and positionable in a retracted position generally coextensive with said flowpath surface;
• means for channeling air along aft facing surfaces of said chutes into said CD nozzle for mixing with said exhaust gases when said chutes are disposed in said deployed position;
• and
• wherein each of said chutes has a generally U-shaped trailing edge including first and second transversely spaced apart legs, a base extending between said legs at radially inner ends thereof, and a top opening extending between said legs at radially outer ends thereof, said trailing edge being positioned in said exhaust gases when said chute is in said deployed position to define a shear perimeter wherein air provided by said channeling means along said trailing edge contacts said exhaust gases for mixing therewith, and said trailing edge being removed from said exhaust gases when said chute is in said retracted position;
• and
• said primary and secondary flaps being positionable in:
• a first position wherein said first throat area A.sub.8 has a maximum value and said chutes are disposed in said deployed position;
• a second position wherein said chutes are disposed in said retracted position and said first throat area A.sub.8 has a value less than said maximum value of said first throat area A.sub.8 ;
• and
• a third position wherein said chutes are disposed in said retracted position, said first throat area A.sub.8 has a value less than said maximum value of said first throat area A.sub.8, and said nozzle outlet area A.sub.9 has a maximum value.