System and method for providing vibration detection in turbomachinery

• US 7,509,862 B2
• Filed: 01/24/2007
• Issued: 03/31/2009
• Est. Priority Date: 01/24/2007
• Status: Expired due to Fees

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Paduano, James D., Cohen, Eric D.
• Primary Examiner(s): Kwok; Helen C.
• Application Number:
  US11/657,216
• Publication Number:
  US 20080177485A1
• Time in Patent Office: 797 Days
• Field of Search: 735/93, 735/83, 73659-660, 702/183, 702/115
• US Class Current: 73/660
• CPC Class Codes: F01D 21/003 Arrangements for testing or measuring for measuring vibrations G01H
• CPC Class Codes: F05D 2260/80 Diagnostics
• CPC Class Codes: F05D 2260/96 Preventing, counteracting or reducing vibration or noise
• CPC Class Codes: F05D 2270/304 Spool rotational speed
• CPC Class Codes: G01H 1/006 of the rotor of turbo machines
• CPC Class Codes: G01M 13/028 Acoustic or vibration analysis
• CPC Class Codes: G01P 3/481 of pulse signals

Abstract

A system and method for providing blade vibration analysis of a turbine is provided. Generally, the system contains a non-contacting sensor capable of determining a distance or velocity of a blade, of the series of blades, in relationship to the sensor. The system also contains a tachometer capable of determining a speed of a shaft of the turbine, and a computer comprising a memory and a processor. The processor is configured by the memory to perform the steps of: processing calibration data of the turbine resulting in a processed calibration signal; processing actual condition data of the turbine, resulting in a processed actual condition signal; calculating a time dilation ratio between a calibration data tachometer window and an actual condition data tachometer window; time dilating either a calibration sensor signal or an actual condition sensor signal using the time dilation ratio, resulting in a time dilated sensor signal; rewindowing the time dilated sensor signal around a zero-crossing point of the time dilated sensor signal, resulting in a derived calibration or actual condition sensor signal; and subtracting the derived calibration or actual condition sensor signal from the processed calibration or actual condition sensor signal.

Claims

1. A system for providing blade vibration analysis of a turbine, wherein the turbine contains a series of blades, a rotor, and a shaft, the system comprising:

a non-contacting sensor capable of determining a distance or velocity of a blade, of said series of blades, in relationship to said sensor, wherein said non-contacting sensor provides a non-contacting sensor signal;

a tachometer capable of determining a speed of said shaft; and

a computer comprising a memory and a processor, said processor configured by said memory to perform the steps of;

processing calibration data of said turbine resulting in a processed calibration signal;

processing actual condition data of said turbine, resulting in a processed actual condition signal;

calculating a time dilation ratio between a calibration data tachometer window and an actual condition data tachometer window;

time dilating either a calibration sensor signal or an actual condition sensor signal using said time dilation ratio, resulting in a time dilated sensor signal;

rewindowing said time dilated sensor signal around a zero-crossing point of said time dilated sensor signal, resulting in a derived calibration or actual condition sensor signal; and

subtracting said derived calibration or actual condition sensor signal from said processed calibration or actual condition signal.

2. The system of claim 1, wherein said processor is further configured by said memory to perform the step of resampling said time dilated sensor signal after said step of time dilating, so that a zero-crossing sample of said time dilated sensor signal resides precisely on zero.

3. The system of claim 1, wherein said non-contacting sensor signal is an eddy current signal and wherein said non-contacting sensor is an eddy current sensor.

4. The system of claim 1, wherein said sensor is a variable reluctance sensor.

5. The system of claim 1, further comprising a series of non-contacting sensors.

6. The system of claim 1, further comprising an amplifier/driver for amplifying/driving said non-contacting sensor.

7. The system of claim 1, wherein said step of processing calibration data, and said step of processing actual condition data further comprise the steps of:

filtering a signal from said tachometer and determining zero-crossing points of said shaft for one revolution of said shaft;

windowing sensor signals located between a desired pair of tachometer zero-crossing points;

selecting a sensor signal of said windowed sensor signals and finding a zero-crossing point of said selected sensor signal;

windowing said selected sensor signal around a zero-crossing point of said selected sensor signal; and

upsampling and sinc interpolating said windowed sensor signal and said selected sensor signal.

8. The system of claim 7, wherein said step of processing calibration data, and said step of processing actual condition data, further comprise the step of recomputing zero crossings of said tachometer signal and said non-contacting sensor signal.

9. The system of claim 7, wherein said step of processing calibration data, and said step of processing actual condition data, further comprise the step of correcting for phase shift error after said step of windowing sensor signals located between a desired pair of tachometer zero-crossing points.

10. The system of claim 8, wherein said step of processing calibration data, and said step of processing actual condition data, further comprise the step of resampling said non-contacting sensor signal, resulting in a zero-crossing sample of said non-contacting sensor signal residing precisely at zero.

11. A method of providing blade vibration analysis of a turbine, wherein the turbine contains a series of blades, a rotor, and a shaft, the method comprising the steps of:

processing calibration data of said turbine resulting in a processed calibration signal;

processing actual condition data of said turbine, resulting in a processed actual condition signal;

calculating a time dilation ratio between a calibration data tachometer window and an actual condition data tachometer window;

time dilating either a calibration sensor signal or an actual condition sensor signal using said time dilation ratio, resulting in a time dilated sensor signal;

rewindowing said time dilated sensor signal around a zero-crossing point of said time dilated sensor signal, resulting in a derived calibration or actual condition sensor signal; and

subtracting said derived calibration or actual condition sensor signal from said processed calibration or actual condition signal.

12. The method of claim 11, further comprising the step of resampling said time dilated sensor signal after said step of time dilating, so that a zero-crossing sample of said dilated sensor signal resides precisely on zero.

13. The method of claim 11, wherein said step of processing calibration data, and said step of processing actual condition data, further comprise the steps of:

filtering a signal from a tachometer and determining zero-crossing points of said shaft for one revolution of said shaft;

windowing sensor signals located between a desired pair of tachometer zero-crossing points;

selecting a sensor signal of said windowed sensor signals and finding a zero-crossing point of said selected sensor signal;

windowing said selected sensor signal around a zero-crossing point of said selected sensor signal; and

upsampling and sine interpolating said windowed sensor signal and said selected sensor signal.

14. The method of claim 13, wherein said step of processing calibration data, and said step of processing actual condition data, further comprise the step of recomputing zero crossings of said tachometer signal and a non-contacting sensor signal of a non-contacting sensor that is capable of determining a distance or velocity of a blade, of said series of blades, in relationship to said non-contacting sensor.

15. The method of claim 13, wherein said step of processing calibration data, and said step of processing actual condition data, further comprise the step of correcting for phase shift error after said step of windowing sensor signals located between a desired pair of tachometer zero-crossing points.

16. The method of claim 14, wherein said step of processing calibration data, and said step of processing actual condition data, further comprise the step of resampling a non-contacting sensor signal of a non-contacting sensor that is capable of determining a distance or velocity of a blade, of said series of blades, in relationship to said non-contacting sensor, resulting in a zero-crossing sample of said non-contacting sensor signal residing precisely at zero.

17. A system for providing blade vibration analysis of a turbine, wherein the turbine contains a series of blades, a rotor, and a shaft, the system comprising:

a non-contacting sensor capable of determining a distance or velocity of a blade, of said series of blades, in relationship to said sensor;

a tachometer capable of determining a speed of said shaft;

logic configured to process calibration data of said turbine resulting in a processed calibration signal;

logic configured to process actual condition data of said turbine, resulting in a processed actual condition signal;

logic configured to calculate a time dilation ratio between a calibration data tachometer window and an actual condition data tachometer window;

logic configured to time dilate either a calibration sensor signal or an actual condition sensor signal using said time dilation ratio, resulting in a time dilated sensor signal;

logic configured to rewindow said time dilated sensor signal around a zero-crossing point of said time dilated sensor signal, resulting in a derived calibration or actual condition sensor signal; and

logic configured to subtract said derived calibration or actual condition sensor signal from said processed calibration or actual condition signal.

18. The system of claim 17, further comprising logic configured to resample said time dilated sensor signal, so that a zero-crossing sample of said time dilated sensor signal resides precisely on zero.