Exhaust plenum for radial diffuser

Abstract

An exhaust gas diffuser for a turbomachine includes a diffuser supported on a turbine rotor, aligned with an axis of said turbine rotor. The diffuser is configured to re-direct turbine exhaust gas substantially ninety degrees from a first direction of flow along the rotor axis. A plenum chamber is in fluid communication with and surrounds an outlet end of the diffuser. The plenum chamber is in fluid communication with a transition duct adapted to supply the exhaust gas to another turbomachine. The plenum chamber expands in volume between the diffuser and the transition duct.

What is claimed is: 
     
         1 . An exhaust gas diffuser for a turbomachine comprising:
 a diffuser supported in a turbine rotor, aligned with an axis of said turbine rotor, said diffuser configured to re-direct turbine exhaust gas substantially ninety degrees from a first direction of flow along said axis; a plenum chamber in fluid communication with and surrounding an outlet end of said diffuser, said plenum chamber in fluid communication with a transition duct adapted to supply the exhaust gas to another turbomachine; wherein said plenum chamber expands in volume in a direction toward said transition duct.   
     
     
         2 . The exhaust gas diffuser of  claim 1  wherein said plenum chamber is comprised in part of a pair of non-parallel side walls and a peripheral edge wall connecting said pair of non-parallel side walls. 
     
     
         3 . The exhaust gas diffuser of  claim 2  wherein one of said pair of non-parallel side walls is substantially perpendicular to said axis. 
     
     
         4 . The exhaust gas diffuser of  claim 3  wherein the other of said pair of non-parallel side walls extends at an angle of 20-50° relative to said one of said non-parallel side walls. 
     
     
         5 . The exhaust gas diffuser of  claim 3  wherein the other of said pair of non-parallel side walls extends at an angle of 35-45° relative to said one of said non-parallel side walls. 
     
     
         6 . The exhaust gas diffuser of  claim 2  wherein said peripheral edge wall comprises a radiused end portion connecting to a pair of straight, substantially parallel top and bottom wall portions. 
     
     
         7 . The exhaust gas diffuser of  claim 6  wherein said radiused end portion lies on one side of said axis and said pair of straight, substantially parallel top and bottom wall portions cross said axis, connecting to said transition duct on an opposite side of said axis. 
     
     
         8 . The exhaust gas diffuser of  claim 7  wherein the other of said pair of non-parallel side walls extends at an angle of 20-50° relative to said one of said non-parallel side walls. 
     
     
         9 . The exhaust gas diffuser of  claim 7  wherein the other of said pair of non-parallel side walls extends at an angle of 35-45° relative to said one of said non-parallel side walls. 
     
     
         10 . A turbomachine comprising:
 a gas turbine section including a turbine rotor;   a radial diffuser disposed along a first axis of said turbine rotor;   an exhaust plenum comprising an inlet receiving a portion of the radial diffuser, said exhaust plenum extending along a second axis substantially perpendicular to said first axis, said plenum chamber expanding in volume along said second axis.   
     
     
         11 . The turbomachine of  claim 1  wherein said plenum chamber is comprised in part of a pair of non-parallel side walls an a peripheral edge wall connecting said pair of non-parallel side walls. 
     
     
         12 . The turbomachine of  claim 11  wherein one of said pair of non-parallel side walls is substantially perpendicular to said axis. 
     
     
         13 . The turbomachine of  claim 12  wherein the other of said pair of non-parallel side walls extends at an angle of 20-50° relative to said one of said non-parallel side walls. 
     
     
         14 . The turbomachine of  claim 12  wherein the other of said pair of non-parallel side walls extends at an angle of 35-45° relative to said one of said non-parallel side walls. 
     
     
         15 . The turbomachine of  claim 11  wherein said peripheral edge wall comprises a radiused end portion connecting to a pair of straight, substantially parallel top and bottom wall portions. 
     
     
         16 . The turbomachine of  claim 15  wherein said radiused end portion lies on one side of said axis and said pair of straight, substantially parallel top and bottom wall portions cross said axis, connecting to said transition duct on an opposite side of said axis. 
     
     
         17 . A combined cycle system comprising: a gas turbine including a turbine rotor extending along a first axis; a heat recovery steam generator; a steam turbine adapted to receive steam from said heat recovery steam generator; a radial diffuser disposed along said first axis; and
 an exhaust plenum comprising an inlet receiving a portion of the radial diffuser, said exhaust plenum extending along a second axis substantially perpendicular to said first axis, said plenum chamber expanding in volume along said second axis and communicating with said heat recovery steam generator.   
     
     
         18 . A combined cycle system of  claim 17  wherein said plenum chamber is comprised in part of a pair of non-parallel side walls an a peripheral edge wall connecting said pair of non-parallel side walls and wherein one of said pair of non-parallel side walls is substantially perpendicular to said axis. 
     
     
         19 . A combined cycle system of  claim 18  wherein the other of said pair of non-parallel side walls extends at an angle of 20-50° relative to said one of said non-parallel side walls. 
     
     
         20 . A combined cycle system of  claim 18  wherein the other of said pair of non-parallel side walls extends at an angle of 35-45° relative to said one of said non-parallel side walls.