FREQUENCY RESPONSE AND HEALTH TRACKER FOR A SYNTHETIC JET GENERATOR

• US 20150104310A1
• Filed: 10/16/2013
• Published: 04/16/2015
• Est. Priority Date: 10/16/2013
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Griffin, Steven F.
• Granted Patent: US 9,428,263 B2
• Time in Patent Office: Days
• US Class Current: 416/1
• CPC Class Codes: B64C 21/04 for blowing
• CPC Class Codes: B64C 21/08 adjustable
• CPC Class Codes: B64C 2230/04 by actively generating fluid flow
• CPC Class Codes: B64C 2230/06 by explicitly adjusting fluid flow, e.g. by using valves, variable aperture or slot areas, variable pump action or variable fluid pressure
• CPC Class Codes: B64C 2230/18 by using small jets that make the fluid flow oscillate
• CPC Class Codes: F04B 51/00 Testing machines, pumps, or pumping installations
• CPC Class Codes: F04F 7/00 Pumps displacing fluids by using inertia thereof, e.g. by generating vibrations therein
• CPC Class Codes: F15D 1/0095 by means of injecting jet pulses of fluid wherein the injected fluid is taken from the fluid and re-injected again, e.g. synthetic jet actuators F15D1/008 takes precedence
• CPC Class Codes: Y02T 50/10 Drag reduction

Abstract

A jet generator is controlled by providing an input signal at a variable frequency to the jet generator and to a simulated electrical load of the jet generator, measuring a difference in signals between the jet generator and the simulated electrical load to identify an optimum flow of a jet generated by the jet generator, and tuning the frequency of the input signal to maintain the jet at the optimum flow.

Claims

1. An apparatus comprising:

a power supply for providing an input signal at a variable frequency to a jet generator effecting a jet and to a simulated electrical load of the jet generator;

detection circuitry for measuring a difference in signals between the jet generator and the simulated electrical load to effect an optimum flow of the jet; and

adjustment circuitry for tuning the variable frequency of the power supply to maintain the jet at the optimum flow.

2. The apparatus of claim 1, wherein the adjustment circuitry is configured to determine a transfer function from the input signal and the difference in signals between the jet generator and the simulated electrical load over a frequency range, for determining control parameters for tuning the variable frequency of the power supply.

3. The apparatus of claim 2, wherein the adjustment circuitry is configured to distinguish alterations in the transfer function indicating degradation of the jet generator.

4. The apparatus of claim 1, wherein the jet generator produces the optimum flow at a resonant frequency of the jet generator.

5. The apparatus of claim 1, wherein the jet generator comprises a synthetic jet.

6. The apparatus of claim 1, wherein the jet generator comprises a piezo-electric device.

7. The apparatus of claim 1, wherein the jet generator comprises an electro-strictive device.

8. The apparatus of claim 1, wherein the jet generator comprises a speaker coil.

9. A control system comprising:

a power supply for providing power at a variable frequency to a jet generator effecting a jet and to a simulated electrical load of the jet generator;

detection circuitry for measuring a difference in current through the jet generator and simulated electrical load to effect an optimum flow of the jet; and

adjustment circuitry for tuning the variable frequency of the power supply to maintain the jet at the optimum flow.

10. The control system of claim 9, further comprising calculation circuitry for determining a transfer function from the power and the difference in current between the jet generator and simulated electrical load over a frequency range, for determining control parameters for the adjustment circuitry.

11. The control system of claim 10, wherein the calculation circuitry is configured to distinguish alterations in the transfer function indicating degradation of the jet generator.

12. The control system of claim 9, wherein the jet generator produces the optimum flow at a resonant frequency of the jet generator.

13. The control system of claim 9, wherein the jet generator comprises a synthetic jet.

14. A method of controlling a jet generator comprising:

providing an input signal at a variable frequency to the jet generator and to a simulated electrical load of the jet generator;

measuring a difference in signals between the jet generator and the simulated electrical load to effect an optimum flow of a jet generated by the jet generator; and

tuning the frequency of the input signal to maintain the jet at the optimum flow.

15. The method of claim 14, further comprising determining a transfer function from the input signal and the difference in signals between the jet generator and the simulated electrical load to determine control parameters for tuning the variable frequency of the input signal.

16. The method of claim 15, further comprising distinguishing alterations in the transfer function indicating degradation of the jet generator.

17. The method of claim 14, wherein the jet generator produces the optimum flow at a resonant frequency of the jet generator.

18. The method of claim 14 wherein the jet generator comprises a synthetic jet.

19. The method of claim 14, wherein the jet generator comprises a piezo-electric device.

20. The method of claim 14, wherein the jet generator comprises an electro-strictive device.

21. The method of claim 14, wherein the jet generator comprises a speaker coil.

22. A method of characterizing and monitoring performance of a synthetic jet generator comprising:

providing an input signal to the synthetic jet generator and to a simulated electrical load of the synthetic generator over an operating frequency range of the synthetic jet generator;

measuring a difference in signals between the jet generator and the simulated electrical load over the operating frequency range;

determining a transfer function from the input signal and the difference in signals between the jet generator and the simulated electrical load; and

using the transfer function to determine control parameters for the input signal to cause the synthetic jet generator to generate an optimum flow.

23. The method of claim 22 comprising:

identifying changes in the transfer function corresponding to a varying resonant frequency of the synthetic jet generator; and

adjusting the control parameters to change a frequency of the input signal to cause the synthetic jet generator to operate at the varying resonant frequency to generate the optimum flow.

24. The method of claim 22 further comprising:

detecting a variation from the transfer function signifying an approaching failure condition; and

adjusting the control parameters to maintain the synthetic jet generator at the optimum flow or adjusting the control parameters to operate the synthetic jet generator at a reduced capacity.

25. The method of claim 24 further comprising sending an alert of the approaching failure condition.

26. The method of claim 22 further comprising:

measuring a difference in signals between the jet generator and the simulated electrical load over the operating frequency range to determine a back emf signature of the jet generator;

detecting a variation from the back emf signature signifying an approaching failure condition; and

adjusting the control parameters to maintain the synthetic jet generator at the optimum flow or adjusting the control parameters to operate the synthetic jet generator at a reduced capacity.

27. The method of claim 24 further comprising sending an alert of the approaching failure condition.