US4581888A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Compressor rotating stall detection and warning system
Assignee: RTX Corp
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Filing: 1983-12-27
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Granted: 1986-04-15
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Expires: 2003-12-27
Abstract
Abstract Nonrecoverable compressor rotating stall in a gas turbine engine is detected virtually at its onset by continuously calculating corrected engine speed and measuring the compressor pressure ratio. Associated with each corrected engine speed is a predetermined, empirically calculated critical pressure ratio. When the actual pressure ratio equals or falls below the critical pressure ratio a nonrecoverable stall has been detected and an output signal is generated which warns the pilot or automatically causes corrective action to be taken.
Inventors
- 👤 Charles W. Schmitzer
- 👤 James B. Kelly
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:48
CPC Classifications
G; G08; G08B; G08B21/00; F; F04; F04D; F04D27/00; F04D27/001
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
190 words
Stall detection apparatus for detecting nonrecoverable rotating stall in a gas turbine engine having a compressor, the apparatus comprising: means for detecting the speed of the compressor and for generating a signal N indicative thereof; means for detecting engine inlet temperature T and for generating a signal indicative thereof; means for receiving said compressor speed signal N and said temperature signal T and for generating a signal therefrom indicative of corrected compressor speed NC; means for detecting the actual pressure ratio P R across the compressor and generating a signal indicative thereof; comparator means for receiving the pressure ratio signal and corrected compressor speed signal and for producing an output signal when P R is less than or equal to a predetermined value P c , which is the pressure ratio at the onset of a rotating stall and which varies with corrected speed NC; and timer means for receiving the output signal from said comparator means and for generating an output signal indicative of the existence of a nonrecoverable rotating stall in the compressor if said comparator means output signal is received continuously for a predetermined period of time.
Claim 2
Dependent Claim
190 words
Stall detection apparatus for detecting nonrecoverable rotating stall in a gas turbine engine having a compressor, the apparatus comprising: means for detecting the speed of the compressor and for generating a signal N indicative thereof; means for detecting engine inlet temperature T and for generating a signal indicative thereof; means for receiving said compressor speed signal N and said temperature signal T and for generating a signal therefrom indicative of corrected compressor speed NC; means for detecting the actual pressure ratio P R across the compressor and generating a signal indicative thereof; comparator means for receiving the pressure ratio signal and corrected compressor speed signal and for producing an output signal when P R is less than or equal to a predetermined value P c , which is the pressure ratio at the onset of a rotating stall and which varies with corrected speed NC; and timer means for receiving the output signal from said comparator means and for generating an output signal indicative of the existence of a nonrecoverable rotating stall in the compressor if said comparator means output signal is received continuously for a predetermined period of time.
Claim 3
Dependent Claim
96 words
The stall detection apparatus according to claim 1, wherein the gas turbine engine is a twin spool engine, having a high and low compressor, said high compressor having an inlet and outlet, and said compressor speed N is the high compressor speed and said means for detecting pressure ratio includes means for measuring the pressure ratio from a point at or upstream of the high compressor inlet to a point at or just downstream of the high compressor outlet, whereby the said pressure ratio P R at least encompasses the pressure ratio across the high compressor.
Claim 4
Dependent Claim
39 words
The stall detection apparatus according to claim 1 wherein said comparator means includes a critical pressure ratio generator for receiving said corrected speed signal and for generating therefrom a signal indicative of the critical pressure ratio P c .
Claim 5
Dependent Claim
75 words
The stall detection apparatus according to claim 1 wherein P c varies approximately directly with NC, and wherein said comparator means includes means for receiving said corrected speed signal and actual pressure ratio signal and for calculating the value NC/P R therefrom, and for producing an output signal when NC/P R exceeds or equals a predetermined constant value K which is the slope of a line representing the direct relationship between P c and NC.
Claim 6
Independent Claim
108 words
A method for detecting nonrecoverable compressor rotating stall in a gas turbine engine having a compressor, comprising the steps of: detecting compressor speed N; detecting engine inlet temperature T; calculating corrected compressor speed NC from N and T; detecting a pressure ratio P R across the compressor; and producing an output signal when P R becomes and remains less than or equal to a predetermined value P c for a predetermined length of time, wherein P c is the pressure ratio at the onset of a rotating stall and varies with corrected engine speed, said output signal being indicative of the existence of nonrecoverable stall in the compressor.
Claim 7
Independent Claim
108 words
A method for detecting nonrecoverable compressor rotating stall in a gas turbine engine having a compressor, comprising the steps of: detecting compressor speed N; detecting engine inlet temperature T; calculating corrected compressor speed NC from N and T; detecting a pressure ratio P R across the compressor; and producing an output signal when P R becomes and remains less than or equal to a predetermined value P c for a predetermined length of time, wherein P c is the pressure ratio at the onset of a rotating stall and varies with corrected engine speed, said output signal being indicative of the existence of nonrecoverable stall in the compressor.
Claim 8
Dependent Claim
40 words
The method according to claim 5 wherein the engine is a twin spool engine, N is the speed of the high spool, and P R is a compressor pressure ratio encompassing at least the pressure ratio across the high spool.
Claim 9
Dependent Claim
17 words
The method according to claim 5 wherein NC/P c is a constant for all corrected compressor speeds.
Claim 10
Independent Claim
94 words
A method for detecting nonrecoverable compressor rotating stall in a gas turbine engine having a compressor, comprising the steps of: detecting compressor speed N; detecting engine inlet temperature T; calculating corrected compressor speed NC from N and T and generating a predetermined critical pressure ratio value P c based thereon which represents the pressure ratio at the onset of a rotating stall; detecting a pressure ratio P R across the compressor; producing a stall signal when P R is equal to or less than P c continuously for a predetermined short period of time.
Claim 11
Independent Claim
94 words
A method for detecting nonrecoverable compressor rotating stall in a gas turbine engine having a compressor, comprising the steps of: detecting compressor speed N; detecting engine inlet temperature T; calculating corrected compressor speed NC from N and T and generating a predetermined critical pressure ratio value P c based thereon which represents the pressure ratio at the onset of a rotating stall; detecting a pressure ratio P R across the compressor; producing a stall signal when P R is equal to or less than P c continuously for a predetermined short period of time.
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) | 1989-04-14 | 1989-10-14 | 1990-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-14 | 1993-10-14 | 1994-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-14 | 1997-10-14 | 1998-04-15 | $7700.00 | Window Closed / Lapsed |