Combined amplitude and frequency measurements for non-contacting turbomachinery blade vibration

• US 8,606,541 B2
• Filed: 06/07/2010
• Issued: 12/10/2013
• Est. Priority Date: 06/12/2009
• Status: Active Grant

• Current Assignee: Mechanical Solutions, Inc.
• Original Assignee: Mechanical Solutions, Inc.
• Inventors: Platt, Michael J., Jagodnik, John J.
• Primary Examiner(s): Kundu, Sujoy
• Assistant Examiner(s): HWANG, TIMOTHY
• Application Number:
  US12/795,124
• Publication Number:
  US 20110098948A1
• Time in Patent Office: 1,282 Days
• Field of Search: 702/56, 736/61
• US Class Current: 702/170
• CPC Class Codes: G01H 1/006 of the rotor of turbo machines

Abstract

A method and apparatus for measuring the vibration of rotating blades, such as turbines, compressors, fans, or pumps, including sensing the return signal from projected energy and/or field changes from a plurality of sensors mounted on the machine housing. One or more of the sensors has a narrow field of measurement and the data is processed to provide the referenced time of arrival of each blade, and therefore the blade tip deflection due to vibration. One or more of the sensors has a wide field of measurement, providing a time history of the approaching and receding blades, and the data is processed to provide frequency content and relative magnitudes of the active mode(s) of blade vibration. By combining the overall tip deflection magnitude with the relative magnitudes of the active modes, the total vibratory stress state of the blade can be determined.

Claims

1. A method of measuring the vibration of a blade comprising:

a) associating at least one first sensor with a blade, the at least one first sensor having a narrow field of measurement;

b) determining blade tip time of arrival data from the at least one first sensor to determine a total blade tip deflection;

c) associating at least one second sensor with the blade, the at least one second sensor having a wide field of view;

d) determining amplitude, frequency and phase data of the blade from the at least one second sensor;

e) determining, by the processor, the vibration of the blade using the blade tip time of arrival data and the amplitude, frequency and phase data; and

f) decomposing, by the processor, the total blade tip deflection into a deflection contribution due to each of the individual active mode of vibration of the blade.

2. The method of claim 1, further comprising using the amplitude and phase data to determine the relative magnitudes of the active modes of vibration of the blade prior to the step of decomposing the total blade tip deflection into a deflection contribution due to each of the individual active modes of vibration of the blade.

3. The method of claim 1, further comprising the step of using known blade vibratory relative stress distribution of the blade to determine a stress contribution due to each of the individual active modes of vibration of the blade.

4. The method of claim 3, further comprising using spectral component combination to determine a total vibratory stress state of the blade.

5. The method of claim 3, further comprising using known or separately determined centrifugal stress distribution of the blade to determine a combined stress state of the blades.

6. The method of claim 1, wherein at least one of the first or second sensors is a light sensor that directs light beams and/or lines towards the blade and measures a reflected component, wherein the light sensor further comprises one of a while light or laser.

7. The method of claim 1, wherein the at least one first sensor and the at least one second sensor is housed within a common casing.

8. The method of claim 1, wherein at least one of the first or second sensors is a radio frequency sensors that direct radar waves towards the blade and measures the frequency and phase modulation due to blade motion.

9. The method of claim 1, wherein at least one of the first or second sensors is an eddy current, inductive, magnetic or capacitive sensor that reacts to the blade moving through a generated field, responding to the moving blade.

10. A method of measuring the vibration of a blade comprising:

a) associating at least one first sensor with a blade, the at least one first sensor having a narrow field of measurement;

b) determining blade tip time of arrival data from the at least one first sensor;

c) associating at least one second sensor with the blade, the at least one second sensor having a wide field of view;

d) determining amplitude, frequency and phase data of the blade from the at least one second sensor;

e) determining, by the processor, the vibration of the blade using the blade tip time of arrival data and the amplitude, frequency and phase data;

f) using the time of arrival data to determine a total blade tip deflection;

g) using the amplitude and phase data to determine the relative magnitudes of the active modes of vibration of the blade; and

h) decomposing, by the processor, the total blade tip deflection into a deflection contribution due to each of the individual active modes of vibration of the blade.

11. The method of claim 10, further comprising the step of using known blade vibratory relative stress distribution of the blade to determine a stress contribution due to each of the individual active modes of vibration of the blade.

12. The method of claim 11, further comprising using spectral component combination to determine a total vibratory stress state of the blade.

13. The method of claim 11, further comprising using known or separately determined centrifugal stress distribution of the blade to determine a combined stress state of the blades.

14. The method of claim 10, wherein at least one of the first or second sensors is a light sensor that directs light beams and/or lines towards the blade and measures a reflected component, wherein the light sensor further comprises one of a while light or laser.

15. The method of claim 10, wherein the at least one first sensor and the at least one second sensor is housed within a common casing.

16. The method of claim 10, wherein at least one of the first or second sensors is a radio frequency sensors that direct radar waves towards the blade and measures the frequency and phase modulation due to blade motion.

17. The method of claim 10, wherein at least one of the first or second sensors is an eddy current, inductive, magnetic or capacitive sensor that reacts to the blade moving through a generated field, responding to the moving blade.

18. The method of claim 10, wherein the blade has a blade tip thickness, and the at least one first sensor has an effective measurement width of substantially equal to or less than the blade tip thickness.

19. The method of claim 10, wherein the blade further comprises a plurality of blade segments having a spacing defined therebetween, and wherein the at least one second sensor has an effective measurement width on the order of the inter-blade spacing.

20. A method of measuring the vibration of a blade comprising:

a) associating a first sensor with a blade, the first sensor having a narrow field of measurement;

b) determining a total blade tip deflection from the first sensor;

c) associating a second sensor with the blade, the second sensor having a wide field of view;

d) determining at least one of the group of amplitude, frequency and phase data of the blade from the second sensor;

e) calculating, by the processor, the total vibrations of the blade from the data from the first and second sensors; and

f) decomposing, by the processor, the total blade tip deflection into a deflection contribution due to each of the individual active modes of vibration of the blade.

21. The method of claim 20, wherein said first sensor has a field of view less than 60 degrees, and wherein said second sensor has a wide field of view of more than 100 degrees.