Buffer system that communicates buffer supply air to one or more portions of a gas turbine engine

Abstract

A gas turbine engine includes a buffer system that can communicate a buffer supply air to a portion of the gas turbine engine. The buffer system includes a first bleed air supply having a first pressure, a second bleed air supply having a second pressure that is greater than the first pressure, and an ejector that selectively augments the first bleed air supply to prepare the buffer supply air for communication to the portion of the gas turbine engine.

1 . A gas turbine engine, comprising:
 a buffer system that communicates a buffer supply air to a portion of the gas turbine engine, wherein said buffer system includes:
 a first bleed air supply having a first pressure; 
 a second bleed air supply having a second pressure that is greater than said first pressure; and 
 an ejector that selectively augments said first bleed air supply to prepare said buffer supply air for communication to said portion of the gas turbine engine. 
   
     
     
         2 . The gas turbine engine as recited in  claim 1 , wherein said ejector is powered by said second bleed air supply. 
     
     
         3 . The gas turbine engine as recited in  claim 1 , wherein said portion includes at least one bearing compartment of the gas turbine engine. 
     
     
         4 . The gas turbine engine as recited in  claim 1 , comprising a controller that selectively commands said ejector to augment said first bleed supply air in response to detecting a power condition of the gas turbine engine. 
     
     
         5 . The gas turbine engine as recited in  claim 4 , comprising a sensor that detects said power condition. 
     
     
         6 . The gas turbine engine as recited in  claim 1 , wherein said first bleed air supply is sourced from a location of the gas turbine engine that is upstream from a source of said second bleed air supply. 
     
     
         7 . The gas turbine engine as recited in  claim 1 , wherein said first bleed air supply is augmented to a higher pressure by said ejector in response to a low power condition of the gas turbine engine and said first bleed air supply is not augmented by said ejector in response to a high power condition of the gas turbine engine. 
     
     
         8 . A gas turbine engine, comprising:
 a compressor section;   a combustor in fluid communication with said compressor section;   a turbine section in fluid communication with said combustor;   at least one shaft that interconnects at least a portion of said compressor section and said turbine section;   a bearing structure that supports said at least one shaft, wherein said bearing structure includes a bearing compartment; and   a buffer system that selectively communicates a buffer supply air to pressurize said bearing compartment, wherein said buffer system includes a first bleed air supply and an ejector that is selectively powered by a second bleed air supply of a greater pressure than said first bleed air supply.   
     
     
         9 . The gas turbine engine as recited in  claim 8 , wherein said ejector augments said first bleed air supply to a higher pressure to prepare said buffer supply air in response to detecting a power condition of the gas turbine engine. 
     
     
         10 . The gas turbine engine as recited in  claim 8 , wherein said ejector augments said first bleed air supply in response to detecting a low power condition of the gas turbine engine. 
     
     
         11 . The gas turbine engine as recited in  claim 8 , wherein the gas turbine engine is a high bypass geared aircraft engine having a bypass ratio of greater than about six (6). 
     
     
         12 . The gas turbine engine as recited in  claim 8 , wherein the gas turbine engine includes a low Fan Pressure Ratio of less than about 1.45. 
     
     
         13 . The gas turbine engine as recited in  claim 8 , comprising a controller that selectively commands said ejector to augment said first bleed supply air in response to detecting a power condition of the gas turbine engine. 
     
     
         14 . The gas turbine engine as recited in  claim 13 , comprising a sensor that detects said power condition. 
     
     
         15 . The gas turbine engine as recited in  claim 8 , wherein said first bleed air supply is sourced from a location of the gas turbine engine that is upstream from a source of said second bleed air supply. 
     
     
         16 . The gas turbine engine as recited in  claim 15 , wherein said first bleed air supply is augmented to a higher pressure by said ejector in response to a low power condition of the gas turbine engine and said first bleed air supply is not augmented by said ejector in response to a high power condition of the gas turbine engine. 
     
     
         17 . A method of cooling a portion of a gas turbine engine, comprising:
 communicating a first bleed air supply and a second bleed air supply to an ejector; and   augmenting the first bleed supply air with the second bleed air supply within the ejector to prepare a buffer supply air for communication to the portion in response to identifying a low power condition of the gas turbine engine.   
     
     
         18 . The method as recited in  claim 17 , comprising the step of:
 communicating the first bleed supply air without augmentation in response to identifying a high power condition of the gas turbine engine.   
     
     
         19 . The method as recited in  claim 17 , comprising the step of:
 identifying a power condition of the gas turbine engine prior to the step of augmenting.   
     
     
         20 . The method as recited in  claim 17 , wherein the low power condition includes one of a ground condition, a ground idle condition and a descent idle condition. 
     
     
         21 . (canceled) 
     
     
         22 . The gas turbine engine as recited in  claim 1 , wherein said first bleed air supply and said second bleed air supply are each sourced from a high pressure compressor of the gas turbine engine. 
     
     
         23 . The gas turbine engine as recited in  claim 1 , wherein said buffer supply air is communicated from said ejector to at least one bearing compartment located upstream from a source of said first bleed air supply and said second bleed air supply. 
     
     
         24 . The method as recited in  claim 17 , comprising the step of:
 communicating a portion of the buffer supply air to a second portion of the gas turbine engine to deice the second portion.   
     
     
         25 . The method as recited in  claim 17 , comprising the step of:
 using a portion of the buffer supply air to ventilate the gas turbine engine.   
     
     
         26 . The method as recited in  claim 17 , comprising the steps of:
 sensing one of the low power condition and a high power condition of the gas turbine engine;   communicating a signal representative of either the low power condition or the high power condition to a controller; and   commanding performance of the augmenting step in response to sensing the low power condition.