Patent ID: 7934904
Filing Date: 2011-05-03
Classification: F01D,F05D

Abstract:
1. Diffuser and exhaust system ( 1 ) for a turbine having an axial-radial diffuser and an exhaust hood ( 8 ), the diffuser and exhaust system comprising an inner flow guide ( 10 ) and an outer flow guide ( 12 ), each extending from a diffuser inlet at a last turbine blade row ( 4 ) to a diffuser outlet, the inner flow guide ( 10 ) extending from a hub ( 5 ) at the last turbine blade row ( 4 ) and the outer flow guide ( 12 ) extending from a turbine casing ( 7 ) at the last blade row ( 4 ), and the diffuser outlet extending from an end portion of the inner flow guide to an end portion of the outer flow guide ( 12 ), and the exhaust hood ( 8 ) comprising a first portion ( 20 ) including an end wall ( 11 ) and a side wall ( 11 ′) extending around approximately half the circumference of the diffuser outlet and a second portion ( 21 ) extending from the first portion ( 20 ) to an exhaust hood outlet ( 22 ), the exhaust hood ( 8 ) comprising two flow passages ( 24 , 25 ) at transition points from the first portion ( 20 ) to the second portion ( 21 ) of the exhaust hood ( 8 ) and between the diffuser outlet and the exhaust hood side wall ( 11 ′), the outer flow guide ( 12 ) comprising a lip ( 13 ) at the diffuser outlet that is rotationally symmetric over a first segment (C-B) of an outer flow guide circumference and comprising a recess ( 14 ) over a second segment (B-C, α) of the circumference, where an angular extent of the second segment (α) of the circumference includes an angular position of one of the two flow passages ( 24 , 25 ), and the second segment (B-C, α) extends over an angular range (α) of up to 140°.