US5165845A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Controlling stall margin in a gas turbine engine during acceleration
Assignee: RTX Corp
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Filing: 1991-11-08
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Granted: 1992-11-24
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Expires: 2011-11-08
Abstract
Abstract Stall margin in a gas turbine compressor is controlled during acceleration by synthesizing the thermal enlargement of critical compressor stages to synthesize the temporary increase in blade-case clearance during acceleration. The change in clearance is used to produce an augmenting stator vane deflection signal which is summed with a steady state vane deflection signal to increase deflection during acceleration until the clearance returns to a nominal level when the expansion of the compressor parts stabilize.
Inventors
- 👤 Syed J. Khalid
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:41
CPC Classifications
F; F02; F02C; F02C9/00; F02C9/16; F02C9/18; F01; F01D; F01D11/00; F01D11/08; F01D11/14; F01D11/20; F04; F04D; F04D27/00; F04D27/02; F04D27/0246; F05; F05D; F05D2200/00; F05D2200/10; F05D2200/11
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
300 words
A control for a gas turbine engine having a compressor comprising a case, disk and rim with compressor blades at a clearance from the case, and stator vanes and a stator vane control to adjust stall margin in the compressor, characterized by: signal processing means comprising: means for providing a first signal with a magnitude that indicates a commanded increase in engine power; means for providing a second signal in response to said first signal, the magnitude of said second signal increasing with time according to expected thermal radical expansion of the engine case; means for providing a third signal in response to said first signal, the magnitude of said third signal increasing with time according to expected thermal radial expansion of the disk; means for providing a fourth signal in response to said first signal, the magnitude of said fourth signal increasing with time according to expected thermal radial expansion of the rim and blades; means for subtracting said third and fourth signals from said second signal to produce a fifth signal, the magnitude of said fifth signal representing the increase in clearance between the blade and the case; means for providing a sixth signal the magnitude of the sixth signal representing an increase, which is a function of the fifth signal, in vane defection; means for providing a seventh signal, the magnitude of which determines a first deflection of the vanes to produce a first engine stall margin; and means for summing said sixth signal with the seventh signal to produce an eighth signal supplied to the stator control to control the deflection of the vanes as a function of the magnitude of the eighth signal and produce a second stall margin greater than said first stall margin as a function of the magnitude of the sixth signal.
Claim 2
Dependent Claim
300 words
A control for a gas turbine engine having a compressor comprising a case, disk and rim with compressor blades at a clearance from the case, and stator vanes and a stator vane control to adjust stall margin in the compressor, characterized by: signal processing means comprising: means for providing a first signal with a magnitude that indicates a commanded increase in engine power; means for providing a second signal in response to said first signal, the magnitude of said second signal increasing with time according to expected thermal radical expansion of the engine case; means for providing a third signal in response to said first signal, the magnitude of said third signal increasing with time according to expected thermal radial expansion of the disk; means for providing a fourth signal in response to said first signal, the magnitude of said fourth signal increasing with time according to expected thermal radial expansion of the rim and blades; means for subtracting said third and fourth signals from said second signal to produce a fifth signal, the magnitude of said fifth signal representing the increase in clearance between the blade and the case; means for providing a sixth signal the magnitude of the sixth signal representing an increase, which is a function of the fifth signal, in vane defection; means for providing a seventh signal, the magnitude of which determines a first deflection of the vanes to produce a first engine stall margin; and means for summing said sixth signal with the seventh signal to produce an eighth signal supplied to the stator control to control the deflection of the vanes as a function of the magnitude of the eighth signal and produce a second stall margin greater than said first stall margin as a function of the magnitude of the sixth signal.
Claim 3
Dependent Claim
48 words
A control according to claim 1, further characterized by: means for multiplying the case, rim, and disk thermal time constants of the second, third, and fourth signals with a ninth signal which is a function of compressor pressure to accurately represent the thermal expansion for all operating conditions.
Claim 4
Dependent Claim
35 words
A control according to claims 1 or 2, further characterized in that: the magnitude of the first signal is calculated from compressor burner pressure, engine inlet total pressure and temperature and a measured engine temperature.
Claim 5
Independent Claim
285 words
A method for controlling stall margin in a gas turbine engine having a compressor comprising a case, disk and rim with compressor blades at a clearance from the case, and stator vanes and a stator vane control to adjust stall margin in the compressor, characterized by the steps: providing a first signal with magnitude that indicates a commanded increase in engine power; providing a second signal in response to said first signal, the magnitude of said second signal increasing with time according to expected thermal radial expansion of the engine case; providing a third signal in response to said first signal, the magnitude of said second signal increasing with time according to expected thermal radial expansion of the disk; providing a fourt signal in response to said first signal, the magnitude of said fourth signal increasing with time according to expected thermal radial expansion of the rim and blades; subtracting said third and fourth signals from said second signal to produce a fifth signal, the magnitude of said fifth signal representing the increase in clearance between the blade and the case; providing a sixth signal, the magnitude of the sixth signal representing an increase, which is a function of the fifth signal, in van deflection; providing a seventh signal, the magnitude of which determines a first deflection of the vanes to produce a first engine stall margin; and summing said sixth signal with the seventh signal to produce an eighth signal supplied to the stator control to control the deflection of the vanes as a function of the magnitude of the eighth signal and produce a second stall margin greater than said first stall margin as a function of the magnitude of the sixth signal.
Claim 6
Independent Claim
285 words
A method for controlling stall margin in a gas turbine engine having a compressor comprising a case, disk and rim with compressor blades at a clearance from the case, and stator vanes and a stator vane control to adjust stall margin in the compressor, characterized by the steps: providing a first signal with magnitude that indicates a commanded increase in engine power; providing a second signal in response to said first signal, the magnitude of said second signal increasing with time according to expected thermal radial expansion of the engine case; providing a third signal in response to said first signal, the magnitude of said second signal increasing with time according to expected thermal radial expansion of the disk; providing a fourt signal in response to said first signal, the magnitude of said fourth signal increasing with time according to expected thermal radial expansion of the rim and blades; subtracting said third and fourth signals from said second signal to produce a fifth signal, the magnitude of said fifth signal representing the increase in clearance between the blade and the case; providing a sixth signal, the magnitude of the sixth signal representing an increase, which is a function of the fifth signal, in van deflection; providing a seventh signal, the magnitude of which determines a first deflection of the vanes to produce a first engine stall margin; and summing said sixth signal with the seventh signal to produce an eighth signal supplied to the stator control to control the deflection of the vanes as a function of the magnitude of the eighth signal and produce a second stall margin greater than said first stall margin as a function of the magnitude of the sixth signal.
Claim 7
Dependent Claim
48 words
A method according to claim 4, further characterized by the steps: multiplying the case, rim, and disk thermal time constants of the second, third, and fourth signals with a ninth signal which is a function of compressor pressure to accurately represent the thermal expansion for all operating conditions.
Claim 8
Independent Claim
34 words
A method according to claims 4 or 5, further characterized by the step: calculating magnitude of the first signal from compressor burner pressure, engine inlet total pressure and temperature and a measured engine temperature.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-11-24 | 1996-05-25 | 1996-11-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-11-24 | 2000-05-25 | 2000-11-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-11-24 | 2004-05-25 | 2004-11-24 | $7700.00 | Window Closed / Lapsed |