Exhaust gas diffuser for a gas turbine

Abstract

An exhaust gas diffuser for a gas turbine generally includes an inner wall that extends along an axial centerline of the exhaust gas diffuser. An outer wall is coaxially aligned with the inner wall. The outer wall is radially separated from the inner wall so as to define a flow passage therebetween. An airfoil shaped strut is disposed in the flow passage. The strut extends between the inner and the outer walls. The strut includes a leading edge and a trailing edge positioned relative to a direction of flow through the flow passage. The leading edge and the trailing edge are tapered from the inner wall to the outer wall in the direction of flow through the passage.

What is claimed is: 
     
         1 . An exhaust gas diffuser for a gas turbine, comprising:
 a. an inner wall extending along an axial centerline of the exhaust gas diffuser;   b. an outer wall coaxially aligned with the inner wall, the outer wall being radially separated from the inner wall to define a flow passage therebetween; and   c. an airfoil shaped strut disposed in the flow passage, the strut extending between the inner and the outer walls, the strut having a leading edge and a trailing edge positioned relative to a direction of flow through the flow passage, the leading edge and the trailing edge being tapered from the inner wall towards the outer wall in the direction of flow.   
     
     
         2 . The exhaust gas diffuser as in  claim 1 , wherein the leading edge and the trialing edge of the strut are parallel. 
     
     
         3 . The exhaust gas diffuser as in  claim 1 , wherein the leading edge and the trailing edge of the strut are non-parallel. 
     
     
         4 . The exhaust gas diffuser as in  claim 1 , further comprising a plurality of the airfoil shaped struts spaced circumferentially around the inner wall. 
     
     
         5 . The exhaust gas diffuser as in  claim 1 , wherein the airfoil shaped strut has a chord length defined along the axial centerline of the exhaust gas diffuser between the leading edge and the trialing edge of the strut, the chord length being constant between the inner and the outer walls. 
     
     
         6 . The exhaust gas diffuser as in  claim 1 , wherein the airfoil shaped strut includes a root portion connected to the inner wall and a tip portion connected to the outer wall, the leading and the trailing edges extending between the root portion and the tip portion. 
     
     
         7 . The exhaust gas diffuser as in  claim 6 , wherein the leading edge at the root portion is disposed upstream from the leading edge at the tip portion and the trailing edge at the root portion is disposed upstream from the trailing edge at the tip portion. 
     
     
         8 . An exhaust gas diffuser, comprising:
 a. an inner wall extending along an axial centerline of the exhaust gas diffuser;   b. an outer wall having a first segment upstream from a second segment, the first and second segments being coaxially aligned with the inner wall, the first and second segments being radially separated from the inner wall to define a flow passage through the exhaust gas diffuser; and   c. an airfoil shaped strut disposed in the flow passage, the strut extending between the inner wall and the first and second segments of the outer wall, the strut having a leading edge and a trailing edge positioned relative to a direction of flow through the flow passage, the leading and trailing edges being tapered in the direction of flow through the passage, the leading edge being tapered from the inner wall towards the first segment of the outer wall and the trailing edge being tapered from the inner wall towards the second segment of the outer wall.   
     
     
         9 . The exhaust gas diffuser as in  claim 8 , wherein the leading edge and the trialing edge of the strut are parallel. 
     
     
         10 . The exhaust gas diffuser as in  claim 8 , wherein the leading edge and the trailing edge of the strut are non-parallel. 
     
     
         11 . The exhaust gas diffuser as in  claim 8 , further comprising a plurality of the airfoil shaped struts spaced circumferentially around the inner wall. 
     
     
         12 . The exhaust gas diffuser as in  claim 8 , wherein the airfoil shaped strut has a chord length defined along the axial centerline of the exhaust gas diffuser between the leading edge and the trialing edge of the strut, the chord length being constant between the inner and the outer walls. 
     
     
         13 . The exhaust gas diffuser as in  claim 8 , wherein the airfoil shaped strut includes a root portion and a tip portion, the root portion being connected to the inner wall and the tip portion being connected to the first segment of the outer wall at the leading edge of the strut and to the second segment of the outer wall at the trailing edge of the strut. 
     
     
         14 . The exhaust gas diffuser as in  claim 13 , wherein the leading edge at the root portion is disposed upstream from the leading edge at the tip portion and the trailing edge at the root portion is disposed upstream from the trailing edge at the tip portion. 
     
     
         15 . A gas turbine comprising:
 a. a compressor section at a forward end of the gas turbine;   b. a combustor downstream from the compressor section;   c. a turbine section downstream from the combustor; and   d. an exhaust gas diffuser downstream from the turbine section, comprising:
 i. an inner wall extending along an axial centerline of the exhaust gas diffuser; 
 ii. an outer wall coaxially aligned with the inner wall, the outer wall being radially separated from the inner wall to define a flow passage therebetween; and 
 iii. an airfoil shaped strut disposed in the flow passage, the strut extending between the inner and the outer walls, the strut having a leading edge and a trailing edge positioned relative to a direction of flow through the flow passage, the leading edge and the trailing edge being tapered from the inner wall towards the outer wall in the direction of flow. 
   
     
     
         16 . The gas turbine as in  claim 15 , wherein the leading edge and the trialing edge of the exhaust gas diffuser airfoil shaped strut are parallel. 
     
     
         17 . The gas turbine as in  claim 15 , wherein the leading edge and the trialing edge of the exhaust gas diffuser airfoil shaped strut non-parallel. 
     
     
         18 . The gas turbine as in  claim 15 , wherein the exhaust gas diffuser further comprises a plurality of the airfoil shaped struts spaced circumferentially around the inner wall. 
     
     
         19 . The gas turbine as in  claim 15 , wherein the airfoil shaped strut has a chord length defined along the axial centerline of the exhaust gas diffuser between the leading edge and the trialing edge of the strut, the chord length being constant between the inner and the outer walls. 
     
     
         20 . The exhaust gas diffuser as in  claim 15 , wherein the airfoil shaped strut includes a root portion connected to the inner wall and a tip portion connected to the outer wall, the leading edge at the root portion being disposed upstream from the leading edge at the tip portion and the trailing edge at the root portion being disposed upstream from the trailing edge at the tip portion.