EXHAUST BRANCH PIPE OF STEAM TURBINE LOW-PRESSURE PART Russian patent published in 2006 - IPC F01D25/30 

FIELD: power engineering; steam turbines.

SUBSTANCE: invention can be used at designing and modification of exhaust branch pipes of steam turbines. Proposed exhaust branch pipe of steam turbine low-pressure part includes diffuser formed by peripheral and root fairings installed with overlapping relative to working blades of last stage and separating part of its area in peripheral and root zones from inlet section of branch pipe. Inlet edges of peripheral and root fairings are arranged at angles to axis of turbine equal to meridional angle of flow in places of their installation and are arranged at a distance from trailing edges of working blades equal to z=C^.δ where C=5-10 is coefficient of action onto working blades; δ is thickness of inlet edges of fairings. Overlapping of peripheral and root fairings relative to working blades is found by formula ▵π=-(A^.L-z^.tgγ_p) ▵k=(B^.L+ztgγ_r) where L is height of working blades; z is distance from fairings to trailing edges of working blades; γ_p, γ_r are meridional angles of flow in places of installation of peripheral and root fairings; A=0.05-0.10 is coefficient of fraction of height of blade in peripheral zone; B=0.10-0.15 is coefficient of fraction of height of blades in root zone.

EFFECT: aerodynamic characteristics of exhaust branch pipe owing to correct arrangement of peripheral and root fairings in steam space, increased economy of turbine, reduced dynamic loads on working blades of last stage and improved reliability of turbine.

2 cl, 4 dwg