Power plants – Combustion products used as motive fluid – Combustion products generator
Reexamination Certificate
1998-09-14
2001-04-24
Kim, Ted (Department: 3746)
Power plants
Combustion products used as motive fluid
Combustion products generator
C060S039230, C137S625470
Reexamination Certificate
active
06220035
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to a combustion system for a gas turbine engine or other heat devices. More particularly, the present invention relates to a system and method for stabilizing the flame in a low NO
x
producing combustor.
BACKGROUND OF THE INVENTION
Gas turbine engines of the type used for industrial applications may employ combustor systems designed to minimize nitrogen oxide emissions. One class of such combustor systems are referred to as lean-premix-prevaporization (LPP) combustors. LPP systems operate by reducing excess air into the combustion zone to control nitrogen oxide levels. This lowers the overall flame temperature, because part of the energy released will be utilized to raise the excess air temperature to reaction temperature. The air and fuel are premixed prior to entering the combustion zone to allow uniform flame temperature. One example of an LPP systems is disclosed in U.S. Pat. No. 5,481,866, entitled Single Stage Premixed Constant Fuel/Air Ratio Combustor, issued to Mowill on Jan. 9, 1996, which is hereby incorporated by reference. Another example of an LPP systems is disclosed in U.S. Pat. No. 6,070,406, entitled “Combustor Dilution Bypass System” and which is assigned to the assignee of this application.
Because LPP systems operate with very lean fuel-to-air ratios, they are always on the edge of blowing out. That is losing the flame in the combustor. As a result, it is not uncommon for these combustors to have bundles of unburnt gas circulating within the combustion chamber. When these bundles finally ignite, they burn fast and create a pressure pulse or wave. These pressure waves may be canceled or reinforced by the reflection of these waves off the combustion chamber liner. If reinforced, a pressure oscillation is created which can damage hardware, cause unacceptable vibration levels, and which may even be audible.
Accordingly, a need exists for stabilizing the flame and thereby eliminate these pressure oscillations in LPP combustor systems.
SUMMARY OF THE INVENTION
In view of the above, it is an object for this invention to provide a LPP combustor system designed for low nitrous oxide emissions having a flame stabilizer that reduces or eliminates pressure oscillations caused by bundles of unburnt gas.
The present invention achieves these objects by providing a lean-premix-prevaporization combustion system that has a combustion chamber and a premixed injector that injects a hot gas, formed from the ignition of a lean mixture of air and fuel, into the combustion chamber. A pilot injector is mounted to the wall of the combustion chamber and injects fuel into the combustion chamber. Upon entering the combustion chamber this fuel ignites to form a fuel rich zone which stabilizes the flame in the combustor.
These and other objects, features and advantages of the present invention are specifically set forth in or will become apparent from the following detailed description of a preferred embodiment of the invention when read in conjunction with the accompanying drawings.
REFERENCES:
patent: 2384783 (1945-09-01), Longenecker
patent: 4255927 (1981-03-01), Johnson et al.
patent: 5230314 (1993-07-01), Kawahara et al.
patent: 5351474 (1994-10-01), Slocum et al.
patent: 5572862 (1996-11-01), Mowill
patent: 5638674 (1997-06-01), Mowill
patent: 5826423 (1998-10-01), Lockyer et al.
patent: 5924276 (1999-07-01), Mowill
Lenertz James E.
Samuel Philip
Allied-Signal Inc.
Desmond, Esq. Robert
Kim Ted
LandOfFree
Annular combustor tangential injection flame stabilizer does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Annular combustor tangential injection flame stabilizer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Annular combustor tangential injection flame stabilizer will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2478833