PLASMA SENSORS AND RELATED METHODS

• US 20090112490A1
• Filed: 10/09/2008
• Published: 04/30/2009
• Est. Priority Date: 10/09/2007
• Status: Active Grant

• Current Assignee: University of Notre DAME Du Lac
• Original Assignee: University of Notre DAME Du Lac
• Inventors: Morris, Scott, Corke, Thomas, Matlis, Eric, Cameron, Joshua
• Granted Patent: US 7,908,115 B2
• Time in Patent Office: Days
• US Class Current: 702/47
• CPC Class Codes: G01F 15/00 Details of, or accessories for, apparatus of groups G01F1/00 - G01F13/00 insofar as such details or appliances are not adapted to particular types of such apparatus
• CPC Class Codes: G01F 15/024 involving digital counting
• CPC Class Codes: G01F 15/046 involving digital counting

Abstract

Plasma sensors, systems and related methods are described. An example method for predicting an event includes providing a carrier signal across two electrodes and forming a plasma between the two electrodes. The example method also includes measuring a modulated signal from the plasma, manipulating the modulated signal to produce a value and comparing the value to a threshold. Finally, the example method includes determining the likelihood of the event based on the comparison.

Claims

1. A method for predicting an event, the method comprising:

providing a carrier signal across two electrodes;

forming a plasma between the two electrodes;

measuring a modulated signal from the plasma;

manipulating the modulated signal to produce a value;

comparing the value to a threshold; and

determining the likelihood of the event based on the comparison.

2. A method as defined in claim 1, wherein the event is a stall of an axial flow device.

3. A method as defined in claim 2, wherein the axial flow device is a compressor.

4. A method as defined in claim 1, wherein the modulated signal is formed from a flow disturbance.

5. A method as defined in claim 4, wherein the flow disturbance is a change in pressure.

6. A method as defined in claim 1, wherein the electrodes are at least one of embedded within or flush with a casing of an axial flow device.

7. A method as defined in claim 1, wherein the electrodes are disposed adjacent to a blade path.

8. A method as defined in claim 7, wherein the electrodes are disposed downstream of a leading edge of a blade.

9. A method as defined in claim 1, wherein a flow disturbance across the plasma occurs at an angle from a velocity flow.

10. A method as defined in claim 1 further comprising wirelessly transmitting the modulated signal.

11. A plasma sensor system comprising:

a carrier signal generator to generate a carrier signal;

at least two electrodes across which the carrier signal is transmitted to form a plasma;

a probe to measure a modulated signal from the plasma; and

a processor to manipulate the modulated signal to produce a value and to compare the value to a threshold, and determine the likelihood of an event based on the comparison.

12. A system as defined in claim 11, wherein the event is a stall of an axial flow device.

13. A system as defined in claim 12, wherein the axial flow device is a compressor.

14. A system as defined in claim 11, wherein the modulated signal is formed from a flow disturbance.

15. A system as defined in claim 11, wherein the flow disturbance is a change in pressure.

16. A system as defined in claim 11, wherein the electrodes are at least one of embedded within or flush with a rotor casing.

17. A system as defined in claim 11, wherein the electrodes are disposed adjacent to a blade path.

18. A system as defined in claim 11, wherein the electrodes are disposed downstream of a leading edge of a rotor.

19. A system as defined in claim 11, wherein a flow disturbance across the plasma occurs at an angle from a velocity flow.

20. A system as defined in claim 11, wherein the modulated signal is wirelessly transmitted.

21. A plasma sensor comprising:

means for capturing across two electrodes evidence of a flow disturbance; and

means for manipulating the evidence to produce a value indicative of the incipience of an event.

22. A plasma sensor as defined in claim 21, wherein the event is a stall of an axial flow device.

23. A plasma sensor as defined in claim 22, wherein the axial flow device is a compressor.

24. A plasma sensor as defined in claim 21, wherein the evidence of the flow disturbance is captured in a modulated signal.

25. A plasma sensor as defined in claim 21, wherein the flow disturbance is a change in pressure.

26. A plasma sensor as defined in claim 21, wherein the electrodes are at least one of embedded within or flush with a rotor casing.

27. A plasma sensor as defined in claim 21, wherein the electrodes are disposed adjacent to a blade path.

28. A plasma sensor as defined in claim 21, wherein the electrodes are disposed downstream of a leading edge of a rotor.

29. A plasma sensor as defined in claim 21, wherein a flow disturbance across the plasma occurs at an angle from a velocity flow.

30. A plasma sensor as defined in claim 21, wherein the modulated signal is wirelessly transmitted.