Altering a natural frequency of a gas turbine transition duct
AssigneeALSTOM Technology Ltd
InventorsHany Rizkalla, Stephen W. Jorgensen, Peter Stuttaford
Life of this patent
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Abstract
A transition duct having a thermally free aft frame and being capable of adjusting the natural frequency is disclosed. The aft frame is capable of permitting movement due to thermal gradients with the transition duct. The transition duct utilizes a spring plate located adjacent to an aft mounting bracket, where the spring plate, based on its thickness can either increase or decrease a frequency of the transition duct. Such an arrangement ensures that the transition duct natural frequency does not coincide with or cross other critical engine and/or combustor frequencies.
Claims14
A transition duct comprising:
- a first panel assembly;
- a generally rectangular aft frame fixed to an exit end of the first panel assembly;
- an inner and outer bulkhead assembly comprising:
- a first inner and first outer, generally arc-shaped bulkhead having a plurality of first through holes;
- a second inner and second outer, generally arc-shaped bulkhead having a plurality of second through holes;
- a plurality of bushings;
- means for fastening the bulkheads and bushings to the aft frame;
- a spring plate capable of being received between attachment portions of the second outer bulkhead, the spring plate having a flat portion extending from a top edge to a bottom edge and merging into parallel curved portions that are perpendicular to the flat portion and immediately adjacent to the attachment portions of the second outer bulkhead;
- an aft mounting bracket for mounting the transition duct to a portion of a turbine frame, the aft mounting bracket coupled to at least the spring plate;
- wherein the aft frame, the inner and outer bulkhead assemblies, the spring plate, and the aft mounting bracket are secured in a manner so as to allow for thermal expansion of the aft frame in at least a circumferential direction while permitting a natural frequency of the transition duct to be altered.
A mounting system for a transition duct capable of altering a natural frequency of the transition duct, the mounting system comprising:
- an outer bulkhead assembly having a first outer bulkhead and a second outer bulkhead, the second outer bulkhead having attachment portions that extend radially outward and generally perpendicular to the second outer bulkhead;
- a spring plate capable of being received by the second outer bulkhead, the spring plate having a flat portion extending from a top edge to a bottom edge and merging into parallel curved portions that are perpendicular to the flat portion and extend so as to be immediately adjacent to the attachment portions of the second outer bulkhead;
- and,
- an aft mounting bracket for mounting the transition duct to a portion of a turbine frame;
- wherein the outer bulkhead assembly, the spring plate, and the aft mounting bracket are secured in a manner so as to alter the natural frequency of the transition duct.
Dependencies are inferred from the claim text.