US4117669A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and method for reducing thermal stress in a turbine rotor
Assignee: National Aeronautics and Space Administration
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Filing: 1977-03-04
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Granted: 1978-10-03
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Expires: 1997-03-04
Abstract
Abstract A gas turbine is provided wherein the thermal stresses in the turbine rotor are reduced. The rotor includes a central disc with a peripheral rim, and a plurality of blades extending radially outwardly from the rim, and to reduce thermal stresses, a duct arrangement is provided which selectively directs hot gases from the turbine combustor to the rim during the turbine start-up. The hot gases from the combustor serve to heat the rim, and thus decease the start-up period necessary to bring the temperature profile of the rotor into the operating temperature range. After the start-up period, the duct arrangement is then used to direct cool gases from the turbine compressor to the rim of the rotor in order to maintain a lower rotor equilibrium temperature.
Inventors
- 👤 Jack A. Heller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:21
CPC Classifications
F; F02; F02C; F02C7/00; F02C7/26
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
82 words
In a turbine comprising a combustor, a rotor having a central disc with a peripheral rim, a plurality of blades extending radially outwardly from said rim, and a flow path for a main flow of hot gases from the combustor to the turbine rotor, the improvement comprising: a duct arrangement bypassing said flow path and in fluid communication with said combustor for directing hot gases from said combustor to the under side of the rim of the rotor during turbine start up.
Claim 2
Dependent Claim
82 words
In a turbine comprising a combustor, a rotor having a central disc with a peripheral rim, a plurality of blades extending radially outwardly from said rim, and a flow path for a main flow of hot gases from the combustor to the turbine rotor, the improvement comprising: a duct arrangement bypassing said flow path and in fluid communication with said combustor for directing hot gases from said combustor to the under side of the rim of the rotor during turbine start up.
Claim 3
Dependent Claim
26 words
A turbine in accordance with claim 1 wherein said duct arrangement includes a flow control valve for regulating the flow of hot gases from the combustor.
Claim 4
Dependent Claim
18 words
A turbine in accordance with claim 2 and including temperature responsive means for actuating said flow control valve.
Claim 5
Dependent Claim
16 words
A turbine in accordance with claim 3 wherein said flow control valve includes a bimetallic member.
Claim 6
Dependent Claim
53 words
A turbine in accordance with claim 1 wherein a peripheral portion of each side of said central disc adjacent said peripheral rim is recessed to expose forward and aft undersides of said rim, and wherein said duct arrangement includes a plurality of injectors for directing hot gases toward said undersides of said rim.
Claim 7
Dependent Claim
66 words
A turbine in accordance with claim 1 wherein said central disc is tapered along radii extending from the center of said central disc, said peripheral rim extending orthogonally outwardly from the radii of said central disc and said peripheral rim having a forward underside and an aft underside, said duct arrangement including a plurality of injectors for directing hot gases toward said undersides of said rim.
Claim 8
Dependent Claim
63 words
A turbine in accordance with claim 2 wherein said duct arrangement includes a flow splitter located downstream from, and in fluid communication with, said flow control valve for dividing the flow of hot gases from said control valve into a first duct directed at the forward underside of said rim and into a second duct directed at the aft underside of said rim.
Claim 9
Dependent Claim
73 words
A turbine in accordance with claim 2 further including a shroud and a structure for supporting said rotor, said shroud being spaced apart from said supporting structure by a plurality of hollow stator blades, said shroud and said supporting structure defining therebetween an annular passageway adapted to receive a main flow of hot gases from said combustor, a portion of the duct arrangement extending through the hollow portion of said hollow stator blades.
Claim 10
Dependent Claim
42 words
A turbine in accordance with claim 2 further including a compressor, said duct arrangement including a further flow control valve, in fluid communication with said compressor, for controlling bleeding of cooling gases from said compressor to cool the underside of said rim.
Claim 11
Independent Claim
97 words
A method for reducing the thermal stress in a rotor of a turbine, said rotor comprising a central disc with a peripheral rim and a plurality of blades extending radially outwardly from said rim, the turbine further including a combustor and a flow path for a main flow of hot gases from the combustor to the turbine rotor, said method comprising the steps of: bleeding hot gases from the combustor of the turbine in bypass relation to said flow path, and directing the hot gases at the underside of the rim of said rotor during turbine start-up.
Claim 12
Independent Claim
97 words
A method for reducing the thermal stress in a rotor of a turbine, said rotor comprising a central disc with a peripheral rim and a plurality of blades extending radially outwardly from said rim, the turbine further including a combustor and a flow path for a main flow of hot gases from the combustor to the turbine rotor, said method comprising the steps of: bleeding hot gases from the combustor of the turbine in bypass relation to said flow path, and directing the hot gases at the underside of the rim of said rotor during turbine start-up.
Claim 13
Dependent Claim
29 words
A method in accordance with claim 10 wherein the flow of hot gases from the combustor is terminated after the rim of the rotor has reached a steady-state temperature.
Claim 14
Dependent Claim
50 words
A method in accordance with claim 11 wherein said turbine further includes a compressor, and the method further comprises the step of bleeding cooling gases from the compressor and directing the cooling gases at the rim of the rotor after the flow of hot gases from the combustor is terminated.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-10-02 | 1982-04-03 | 1982-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-10-02 | 1986-04-03 | 1986-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-10-02 | 1990-04-03 | 1990-10-03 | $7700.00 | Window Closed / Lapsed |