Variable area exhaust mixer for a gas turbine engine

Abstract

A variable area exhaust mixer is provided for a gas turbine engine. The variable area exhaust mixer includes an outer wall with a multiple of doors. Each of the multiple of doors is operable to control a passage entrance into at least one of a multiple of circumferentially arrayed vanes with a respective strut flow passage which essentially alters its bypass ratio during flight to match requirements.

What is claimed is: 
     
         1 . A variable cycle gas turbine engine, comprising:
 a variable area exhaust mixer between a third stream fan flow path and a core flow path;   the variable area exhaust mixer operable to control flow from the third stream fan flow path to the core flow path through a multiple of circumferentially arrayed vanes.   
     
     
         2 . The variable cycle gas turbine engine of  claim 1 , further comprising a second stream fan flow path radially inboard of the third stream fan flow path and radially outboard of the core flow path. 
     
     
         3 . The variable cycle gas turbine engine of  claim 2 , wherein the second stream fan flow path and the third stream fan flow path is downstream of a fan section. 
     
     
         4 . The variable cycle gas turbine engine of  claim 1 , wherein
 the variable area exhaust mixer includes a multiple of doors; and   each of the multiple of doors is operable to control a passage entrance into at least one of the multiple of circumferentially arrayed vanes with a respective strut flow passage.   
     
     
         5 . The variable cycle gas turbine engine of  claim 1 , wherein each of the multiple of doors hinge about an axis generally parallel to a longitudinal engine axis of a gas turbine engine. 
     
     
         6 . The variable cycle gas turbine engine of  claim 5 , wherein each of the multiple of circumferentially arrayed vanes includes a respective trailing edge flap operable to control a passage exhaust from the respective strut flow passage. 
     
     
         7 . The variable cycle gas turbine engine of  claim 6 , wherein each of the trailing edge flaps hinge about an axis generally transverse to a longitudinal engine axis of the gas turbine engine. 
     
     
         8 . The variable cycle gas turbine engine of  claim 1 , wherein at least one of the multiple of circumferentially arrayed vanes includes one or more spray bars from a fuel manifold to direct fuel through the multiple of circumferentially arrayed vanes to selectively inject fuel to provide thrust augmentation. 
     
     
         9 . The variable cycle gas turbine engine of  claim 1 , further comprising a tail cone radially inboard of the multiple of circumferentially arrayed vanes. 
     
     
         10 . A method of operating a gas turbine engine comprising selectively changing an area-ratio between a fan flow in a third stream bypass flow path and a core flow through a core flow path downstream of a turbine section. 
     
     
         11 . The method of  claim 10 , further comprising selectively changing the area-ratio by about 20%-50%.