SONIC MEANS FOR DETECTING COMPRESSOR STALL

• US 3,872,292 A
• Filed: 07/26/1973
• Issued: 03/18/1975
• Est. Priority Date: 07/26/1973
• Status: Expired due to Term

• Current Assignee: William H. Dawson Jr
• Original Assignee: William H. Dawson Jr
• Inventors: Dawson, William H. Jr.
• Primary Examiner(s): Morrison, Malcolm A.
• Assistant Examiner(s): Smith, Jerry
• Application Number:
  US05/382,806
• Time in Patent Office: 600 Days
• Field of Search: 235/150.2,151.3 340/27SS 73/116,117.1,117.2,117.3,69 137/15.2 60/239,368
• US Class Current: 700/79
• CPC Class Codes: F04D 27/02 Surge control surge detection F04D27/001
• CPC Class Codes: G06G 7/64 for non-electric machines, e.g. turbine

Abstract

A system for providing a warning signal when certain sensed turbine engine operating conditions, specifically certain measured noise levels, indicate a compressor stall is about to occur. A sensing system includes two microphones placed at separate locations on the engine and a tachometer. A computer includes two function generating units, the first unit providing a measured sonic parameter from the microphone signals and the second unit producing a computed sonic parameter from stored empirical engine data as a function of the engine rotational speed. The two sonic parameters thus obtained are fed into a comparator, which provides a stall warning signal when the two signals are equal, indicating incipient compressor stall.

Claims

1. A condition detection system for rotating machinery comprising:

first and second sonic detectors located at discrete and separate locations on the machinery for generating respective first and second signals;

a speed detector for generating a third signal indicative of the rotational speed of the machinery; and

computer means connected to receive said first, second and third signals for producing an output signal indicative of the condition.

2. A system according to claim 1 wherein said computer means further comprises:

first function generator means receiving said fiRst and second signals for producing a fourth signal indicative of an actual machinery operating condition;

second function generator means receiving said third signal for producing a fifth signal as a function of said third signal and indicative of a predetermined limit of the machinery condition; and

comparator means receiving said fourth and fifth signals for producing an output signal indicative of the difference therebetween.

3. A system according to claim 2 wherein said first function generator means further comprises:

a differentiator connected to receive said first signal for producing an output signal indicative of the rate of change thereof;

divider means connected to receive said first signal and said differentiator output signal for producing output signals indicative of the respective reciprocals of the received signals;

a filter connected to receive said second signal for producing an output signal indicative of discrete frequencies thereof; and

a multiplier connected to receive said divider means output signals and said filter output signal for producing said fourth signal.

4. A system according to claim 3 wherein said fifth signal is generated from empirical data indicative of the condition limit and corresponds with said fourth signal.

5. A system for detecting impending compressor stall in a turbine engine comprising:

first and second sonic detectors located at discrete and separate locations on the engine for generating respective first and second signals;

a speed detector for generating a third signal indicative of the engine rotational speed; and

computer means connected to receive said first, second and third signals for producing an output signal indicative of impending compressor stall.

6. A system according to claim 5 wherein said first sonic detector is juxtapositioned from a mid-compressor stage.

7. A system according to claim 6 wherein said second sonic detector is juxtapositioned from a first compressor stage.

8. A system according to claim 7 wherein said computer means further comprises:

first function generator means receiving said first and second signals for producing a fourth signal indicative of an actual turbine engine operating condition;

second function generator means receiving said third signal for producing a fifth signal indicative of a predetermined limit of impending compressor stall as a function of said third signal;

comparator means receiving said fourth and fifth signals for producing an output signal indicative of the difference therebetween.

9. A system according to claim 8 wherein said first function generator means further comprises:

a differentiator connected to receive said first signal for producing an output signal indicative of the rate of change thereof;

divider means connected to receive said first signal and said differentiator output signal for producing output signals indicative of the respective reciprocals of the received signals;

a filter connected to receive said second signal for producing an output signal indicative of discrete frequencies thereof; and

a multiplier connected to receive said divider means output signals and said filter output signal for producing said fourth signal.

10. A system according to claim 8 wherein said fifth signal is generated from empirical data indicative of a compressor stall limit and corresponds with said fourth signal.

11. A computer for detecting a rotating machinery condition comprising:

first function generator means for receiving first and second sonic signals and producing an output signal indicative of an actual machinery operating condition;

second function generator means for receiving a signal indicative of the rotational speed of the machinery and producing an output signal as a function of the received signal and indicative of a predetermined limit of the machinery condition; and

comparator means receiving said first and said second function generator Means output signals for producing an output signal indicative of the difference therebetween.

12. A computer according to claim 11 wherein said first function generator means further comprises:

a differentiator receiving the first sonic signal for producing an output signal indicative of the rate of change thereof;

divider means connected to receive the first sonic signal and said differentiator output signal for producing output signals indicative of the respective reciprocals of the received signals;

a filter connected to receive the second sonic signal for producing an output signal indicative of discrete frequencies thereof; and

a multiplier connected to receive said divider means output signals and said filter output signal for producing said first function generator means output signal.

13. A computer according to claim 12 wherein said second function generator means output signal is generated from empirical data indicative of the condition limit and corresponds with said first function generator means output signal.

14. A condition detection system for rotating machinery comprising:

first and second sonic detectors located at discrete and separate locations on the machinery for respectively generating a first signal MB and a second signal CB;

a speed detector for generating a third signal indicative of the rotational speed of the machinery; and

computer means including first function generator means connected to receive said first and second signals for producing an output signal according to the formula, CB/MBMB where;

CB Compressor broadband sonic signal MB Turbine engine broadband sonic signal MB Rate of change of MB, second function generator means connected to receive said third signal for producing an output signal as a function of said third signal generated from empirical data according to the formula, CB/MBMB, and comparator means receiving said respective first and second function generator means output signals for producing an output signal indicative of the difference therebetween.