Diffuser and exhaust system for turbine
AssigneeALSTOM Technology Ltd
InventorsLale DEMIRAYDIN, Ralf Greim
Life of this patent
Estimating the term…
Abstract
A diffuser and exhaust system is provided for a turbine having an axial-radial diffuser and an exhaust hood including diffuser inner and outer flow guides that extend from an inlet to an outlet. The exhaust hood includes two throats or flow passages between the diffuser outlet and an exhaust hood side wall. The outer flow guide includes a recess, at one of the said two flow passages. The flow passage is positioned in relation to a point in the exhaust hood in the direction of the tangential flow velocity vector, where the point in the exhaust hood is farthest away from the exhaust hood outlet. The recess prevents a re-acceleration of the flow within the exhaust hood and affects an increase in the performance of the diffuser and exhaust hood system.
Claims11
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°.
Dependencies are inferred from the claim text.