Power plants – Combustion products used as motive fluid – Having mounting or supporting structure
Reexamination Certificate
2002-08-14
2003-12-16
Gartenberg, Ehud (Department: 3746)
Power plants
Combustion products used as motive fluid
Having mounting or supporting structure
C060S800000
Reexamination Certificate
active
06662567
ABSTRACT:
BACKGROUND OF INVENTION
This invention applies to the combustor section of gas turbine engines used in powerplants to generate electricity. More specifically, this invention relates to the structure that transfers hot combustion gases from a can-annular combustor to the inlet of a turbine.
In a typical can-annular gas turbine engine, a plurality of combustors are arranged in an annular array about the engine. The combustors receive pressurized air from the engine's compressor, add fuel to create a fuel/air mixture, and combust that mixture to produce hot gases. The hot gases exiting the combustors are utilized to turn a turbine, which is coupled to a shaft that drives a generator for generating electricity.
The hot gases are transferred from each combustor to the turbine by a transition duct. Due to the position of the combustors relative to the turbine inlet, the transition duct must change cross-sectional shape from a generally cylindrical shape at the combustor exit to a generally rectangular shape at the turbine inlet. In addition the transition duct undergoes a change in radial position, since the combustors are rigidly mounted radially outboard of the turbine.
The combination of complex geometry changes, rigid mounting means, as well as high operating temperatures seen by the transition duct create a harsh operating environment that can lead to premature deterioration, requiring repair and replacement of the transition ducts. To withstand the hot temperatures from the combustor gases, transition ducts are typically cooled, usually by air, either with internal cooling channels or impingement cooling. Severe cracking has occurred with internally air-cooled transition ducts having certain geometries that are rigidly mounted to the turbine inlet and operate in a high temperature environment. This cracking may be attributable to a variety of factors. Specifically, high steady stresses in the region around the aft end of the transition duct exist where sharp geometry changes occur and a rigid mount is located. Such a rigid mount located at the transition duct aft end does not allow for adequate movement due to thermal growth of the transition duct. In addition stress concentrations have been found that can be attributed to sharp corners where cooling holes intersect the internal cooling channels in the transition duct. Further complicating the high stress conditions are extreme temperature differences between portions of the transition duct.
The present invention seeks to overcome the shortfalls described in the prior art by specifically addressing the high steady stresses attributed to the rigid mounting system by providing an improved mounting system for connecting a transition duct to the inlet of a turbine. Typical mounting systems are fixed to the transition duct by a means such as welding and provide holes in the mount for bolting the transition duct to the turbine inlet. Having a fixed mounting system does not provide a means for compensating for changes in duct geometry and positioning due to thermal growth. The present invention overcomes this issue by providing a mounting system containing a plurality of bearings which allow the transition duct to adjust to thermal growth changes at points close in proximity to the turbine mounting points.
REFERENCES:
patent: 4016718 (1977-04-01), Lauck
patent: 4422288 (1983-12-01), Steber
patent: 4719748 (1988-01-01), Davis, Jr. et al.
patent: 4987736 (1991-01-01), Ciokajlo et al.
patent: 5249419 (1993-10-01), Landhuis
patent: 5414999 (1995-05-01), Barnes
patent: 5572863 (1996-11-01), Wrightham et al.
patent: 5706646 (1998-01-01), Wilde et al.
patent: 5761898 (1998-06-01), Barnes et al.
patent: 6345494 (2002-02-01), Coslow
patent: 6442946 (2002-09-01), Kraft et al.
patent: 6568187 (2003-05-01), Jorgensen et al.
Gartenberg Ehud
Power Systems Mfg, LLC
LandOfFree
Transition duct mounting system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Transition duct mounting system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Transition duct mounting system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3134262