External mixing chamber for a gas turbine engine with cooled turbine cooling air

Abstract

A gas turbine engine comprises a compressor section and a turbine section, the compressor section having a last compressor stage. High pressure cooling air is tapped from a location downstream of the last compressor stage and passed through a heat exchanger. Lower pressure air passes across the heat exchanger to cool the high pressure cooling air. A housing surrounds the compressor section and the turbine section and there being a space radially outwardly of the housing, and a mixing chamber received in the space radially outwardly of the housing, the mixing chamber receiving the high pressure cooling air downstream of the heat exchanger, and further receiving air at a temperature higher than a temperature of the high pressure cooling air downstream of the heat exchanger. Mixed air from the mixing chamber is returned into the housing and utilized to cool at least the turbine section.

1 . A gas turbine engine comprising:
 a propulsor, a compressor section and a turbine section, said compressor section having a last compressor stage;   high pressure cooling air tapped from a location downstream of said last compressor stage and passed through a heat exchanger;   lower pressure air passing across said heat exchanger to cool said high pressure cooling air;   a housing surrounding said compressor section and said turbine section and there being a space radially outwardly of said housing, and a mixing chamber received in said space radially outwardly of said housing, said mixing chamber connected to receive said high pressure cooling air at a location downstream of said heat exchanger, and further connected to receive air at a temperature higher than a temperature of said high pressure cooling air taken downstream of said heat exchanger;   mixed air from said mixing chamber returned into said housing and utilized to cool at least one of said turbine section or said last compressor stage;   wherein said high pressure cooling air is tapped from a diffuser section radially outwardly of a combustor located intermediate said compressor section and said turbine section; and   wherein said mixed air passes through a compressor diffuser downstream of said last compressor stage.   
     
     
         2 . The gas turbine engine as set forth in  claim 1 , wherein said mixing chamber has diverters to cause a change in a flow direction from said higher pressure cooling air and said air at a higher temperature. 
     
     
         3 . The gas turbine engine as set forth in  claim 2 , wherein said diverters cause a change in a flow direction of the high pressure cooling air and a flow direction of said air at a higher temperature. 
     
     
         4 . The gas turbine engine as set forth in  claim 3 , wherein said diverters cause said high pressure cooling air to swirl and said air at a higher temperature to swirl. 
     
     
         5 . The gas turbine engine as set forth in  claim 4 , wherein said compressor section includes a low pressure compressor and a high pressure compressor and said turbine section including at least a high pressure turbine and a propulsor drive turbine, and said propulsor drive turbine driving said propulsor through a gear reduction. 
     
     
         6 . The gas turbine engine as set forth in  claim 5 , wherein said propulsor is a fan rotor. 
     
     
         7 . The gas turbine engine as set forth in  claim 4 , wherein said swirl caused by said diverters provide efficient and thorough mixing of said high pressure cooling air and said air at a higher temperature. 
     
     
         8 . The gas turbine engine as set forth in  claim 3 , wherein said compressor section includes a low pressure compressor and a high pressure compressor and said turbine section including at least a high pressure turbine and a propulsor drive turbine, and said propulsor drive turbine driving said propulsor through a gear reduction. 
     
     
         9 . The gas turbine engine as set forth in  claim 2 , wherein said compressor section includes a low pressure compressor and a high pressure compressor and said turbine section including at least a high pressure turbine and a propulsor drive turbine, and said propulsor drive turbine driving said propulsor through a gear reduction. 
     
     
         10 . A gas turbine engine comprising:
 a propulsor, a compressor section and a turbine section, said compressor section having a last compressor stage;   high pressure cooling air tapped from a location downstream of said last compressor stage and passed through a heat exchanger;   lower pressure air passing across said heat exchanger to cool said high pressure cooling air;   a housing surrounding said compressor section and said turbine section and there being a space radially outwardly of said housing, and a mixing chamber received in said space radially outwardly of said housing, said mixing chamber connected to receive said high pressure cooling air at a location downstream of said heat exchanger, and further connected to receive air at a temperature higher than a temperature of said high pressure cooling air taken downstream of said heat exchanger;   mixed air from said mixing chamber returned into said housing and utilized to cool at least one of said turbine section or said last compressor stage;   wherein said high pressure cooling air is tapped from a diffuser section radially outwardly of a combustor located intermediate said compressor section and said turbine section;   wherein said mixed air passes through a compressor diffuser downstream of said last compressor stage; and   wherein said compressor section includes a low pressure compressor and a high pressure compressor and said turbine section including at least a high pressure turbine and a propulsor drive turbine, and said propulsor drive turbine driving said propulsor through a gear reduction.   
     
     
         11 . The gas turbine engine as set forth in  claim 10 , wherein said propulsor is a fan rotor. 
     
     
         12 . The gas turbine engine as set forth in  claim 11 , wherein the fan rotor has a plurality of fan blades, and a low fan pressure ratio is defined across the fan blades alone, and said low fan pressure ratio being less than or equal 1.45. 
     
     
         13 . The gas turbine engine as set forth in  claim 12 , further comprising a low corrected fan tip speed of less than 1150 ft/second. 
     
     
         14 . The gas turbine engine as set forth in  claim 11 , further comprising a low corrected fan tip speed of less than 1150 ft/second. 
     
     
         15 . The gas turbine engine as set forth in  claim 11 , wherein an outer housing surrounds said fan rotor, and said fan delivering air into a bypass duct defined between said outer housing and an inner core engine, and further delivering air to said compressor section with a bypass ratio defined as the volume of air delivered into the bypass duct compared to the volume of air delivered to said compressor section, and said bypass ratio being greater than or equal to 10.0. 
     
     
         16 . The gas turbine engine as set forth in  claim 10 , wherein said propulsor drive turbine having a pressure ratio defined as a ratio of a pressure measured prior to an inlet to said propulsor drive turbine as related to a pressure aft an outlet of the propulsor drive turbine, prior to an exhaust nozzle, and said pressure ratio being greater than or equal to 5.0. 
     
     
         17 . The gas turbine engine as set forth in  claim 10 , wherein said gear reduction having a gear ratio greater than or equal to 2.3. 
     
     
         18 . The gas turbine engine as set forth in  claim 10 , wherein said mixing chamber has diverters to cause a change in a flow direction from said higher pressure cooling air and said air at a higher temperature. 
     
     
         19 . The gas turbine engine as set forth in  claim 18 , wherein said diverters cause a change in a flow direction of the high pressure cooling air and a flow direction of said air at a higher temperature. 
     
     
         20 . The gas turbine engine as set forth in  claim 19 , wherein said diverters cause said high pressure cooling air to swirl and air at a higher temperature to swirl.