Paraelectric gas flow accelerator

• US 6,200,539 B1
• Filed: 07/20/1999
• Issued: 03/13/2001
• Est. Priority Date: 01/08/1998
• Status: Expired due to Term

• Current Assignee: United States of America As REP By The Administrator of The National Aeronautics & Space, University of Tennessee Research Foundation (University of Tennessee)
• Original Assignee: The University Of Tennessee Research Corporation (University of Tennessee)
• Inventors: Sherman, Daniel M., Wilkinson, Stephen P., Roth, J. Reece
• Primary Examiner(s): Mayekar, Kishor
• Application Number:
  US09/357,403
• Time in Patent Office: 602 Days
• Field of Search: 204/164, 422/186.04, 422/22, 588/277
• US Class Current: 216/67
• CPC Class Codes: F05D 2270/172 by a plasma generator, e.g. control of ignition
• CPC Class Codes: H05H 1/2439 Surface discharges, e.g. air flow control

Abstract

A substrate is configured with first and second sets of electrodes, where the second set of electrodes is positioned asymmetrically between the first set of electrodes. When a RF voltage is applied to the electrodes sufficient to generate a discharge plasma (e.g., a one-atmosphere uniform glow discharge plasma) in the gas adjacent to the substrate, the asymmetry in the electrode configuration results in force being applied to the active species in the plasma and in turn to the neutral background gas. Depending on the relative orientation of the electrodes to the gas, the present invention can be used to accelerate or decelerate the gas. The present invention has many potential applications, including increasing or decreasing aerodynamic drag or turbulence, and controlling the flow of active and/or neutral species for such uses as flow separation, altering heat flow, plasma cleaning, sterilization, deposition, etching, or alteration in wettability, printability, and/or adhesion.

Claims

1. An apparatus for generating a flow in gas, comprising:

(a) a substrate;

(b) a first plurality of electrodes configured on the substrate;

(c) a second plurality of electrodes configured on the substrate, wherein each electrode in the second plurality is positioned along a first direction between a pair of adjacent electrodes in the first plurality such that said each electrode is closer to one electrode of the pair of the adjacent electrodes than to another electroed of the pair of adjacent electrodes; and

(d) a voltage generator configured to the first and second pluralities of electrodes and adapted to apply a voltage to the first and second pluralities of electrodes to generate a discharge plasma in the gas located on at least one side of the substrate adjacent to one of the pluralities of electrodes, wherein the relative positioning of the first and second pluralities of electrodes along the first direction results in a force being imparted onto the gas parallel to the first direction.

2. The invention of claim 1, wherein force is imparted onto active species in the discharge plasma which in turn imparts force onto neutral background gas.

3. The invention of claim 1, wherein the substrate is made of a dielectric material.

4. The invention of claim 1, wherein:

the first plurality of electrodes is a set of parallel electrode strips mounted onto a first side of the substrate; and

the second plurality of electrodes is a set of parallel electrode strips mounted onto a second side of the substrate.

5. The invention of claim 4, wherein the first and second pluralities of parallel electrode strips are mounted perpendicular to the first direction.

6. The invention of claim 1, wherein the voltage generator generates an AC voltage of less than about 20 kilovolts with a frequency of less than about 20 kilohertz.

7. The invention of claim 1, wherein the gas has a pressure of about one atmosphere.

8. The invention of claim 7, wherein the discharge plasma is a one-atmosphere, uniform glow discharge (OAUGD) plasma.

9. The invention of claim 1, wherein the force imparted onto the gas accelerates or decelerates the gas.

10. The invention of claim 1, wherein:

force is imparted onto active species in the discharge plasma which in turn imparts force onto neutral background gas;

the substrate is made of a dielectric material;

the first plurality of electrodes is a set of parallel electrode strips mounted onto a first side of the substrate;

the second plurality of electrodes is a set of parallel electrode strips mounted onto a second side of the substrate;

the first and second pluralities of parallel electrode strips are mounted perpendicular to the first direction;

the voltage generator generates an AC voltage of less than about 20 kilovolts with a frequency of less than about 20 kilohertz;

the gas has a pressure of about one atmosphere; and

the discharge plasma is a one-atmosphere, uniform glow discharge (OAUGD) plasma.

11. A method for generating a flow in gas, comprising the steps of:

(a) providing a substrate configured with first and second pluralities electrodes, wherein each electrode in the second plurality is positioned along a first direction between a pair of adjacent electrodes in the first plurality such that said each electrode is closer to one electrode of the pair of the adjacent electrodes than to another electrode of the pair of adjacent electrodes; and

(b) applying a voltage to the first and second pluralities of electrodes to generate a discharge plasma in the gas located on at least one side of the substrate adjacent to one of the pluralities of electrodes, wherein the relative positioning of the first and second pluralities of electrodes along the first direction results in a force being imparted onto the gas parallel to the first direction.

12. The invention of claim 11, wherein force is imparted onto active species in the discharge plasma which in turn imparts force onto neutral background gas.

13. The invention of claim 11, wherein the substrate is made of a dielectric material.

14. The invention of claim 11, wherein:

the first plurality of electrodes is a set of parallel electrode strips mounted onto a first side of the substrate; and

the second plurality of electrodes is a set of parallel electrode strips mounted onto a second side of the substrate.

15. The invention of claim 14, wherein the first and second pluralities of parallel electrode strips are mounted perpendicular to the first direction.

16. The invention of claim 11, wherein the voltage is an RF voltage of less than about 20 kilovolts with a frequency of less than about 20 kilohertz.

17. The invention of claim 11, wherein the gas has a pressure of about one atmosphere.

18. The invention of claim 17, wherein the discharge plasma is a one-atmosphere, uniform glow discharge (OAUGD) plasma.

19. The invention of claim 11, wherein the force imparted onto the gas accelerates or decelerates the gas.

20. The invention of claim 11, wherein:

force is imparted onto active species in the discharge plasma which in turn imparts force onto neutral background gas;

the substrate is made of a dielectric material;

the first plurality of electrodes is a set of parallel electrode strips mounted onto a first side of the substrate;

the second plurality of electrodes is a set of parallel electrode strips mounted onto a second side of the substrate;

the first and second pluralities of parallel electrode strips are mounted perpendicular to the first direction;

the voltage is an RF voltage of less than about 20 kilovolts with a frequency of less than about 20 kilohertz;

the gas has a pressure of about one atmosphere; and

the discharge plasma is a one-atmosphere, uniform glow discharge (OAUGD) plasma.

21. The invention of claim 11, wherein the method is used to increase or decrease aerodynamic drag or turbulence.

22. The invention of claim 11, wherein the method is used to control the flow of the gas during flow separation.

23. The invention of claim 11, wherein the method is used to alter heat flow.

24. The invention of claim 11, wherein the substrate has a form of a conduit and the method is used to move the gas through the conduit.

25. The invention of claim 24, wherein the conduit is one of medical tubing, an air duct, a flue stack, an industrial exhaust stack, or a pipeline.

26. The invention of claim 11, wherein the method is used to manipulate active species for treatment of surfaces located near the substrate, wherein the treatment is one of plasma cleaning, sterilization, deposition, etching, alteration in wettability, alteration in printability, and alteration in adhesion.

27. The invention of claim 11, wherein the method is used to provide momentum to the substrate.

28. The invention of claim 11, wherein the method is used to induce low-speed laminar flow in a low-specd wind tunnel.

29. The invention of claim 11, wherein the method is used for pumping of air in a heating, ventilating, and air conditioning (HVAC) system.

30. The invention of claim 11, wherein the method is used to pump recirculating air in a hospital operating room laminar air flow installation.

31. The invention of claim 11, wherein the method is used to pump recirculating or single-pass air or other gases in a remote exposure reactor.

32. The invention of claim 31, wherein the remote exposure reactor is used to decontaminate surfaces compromised by chemical or biological warfare agents.

33. The invention of claim 11, wherein the method is used to pump input working gases over workpieces of a OAUGD plasma reactor to control dwell time, uniformity of effect, uniformity of the OAUGD plasma, formation of dust and oils, deposition of dust or oils, or to maximize utilization of rare or expensive feed gases.

34. The invention of claim 11, wherein the method is used to provide gas mixing or axial pressure equalization in a high-power laser energized by a plasma discharge.

35. The invention of claim 11, wherein the method is used to provide animated effects in an advertising sign or related two-dimensional effects in or on a plasma panel.

36. The invention of claim 11, wherein the method is used to provide a control mechanism in a pneumatic flow control device.

37. The invention of claim 11, wherein the method is used for flow separation control on airfoils, gas compressor inlets, engine nacelle inlets, or other aerodynamic bodies by direct momentum augmentation, stream-wise vortex creation, or turbulent tripping of an initially laminar boundary layer.

38. The invention of claim 11, wherein the method is used for flow mixing or heat transfer augmentation by stream-wise vortex creation or turbulent tripping of an initially laminar boundary layer.

39. The invention of claim 11, wherein the method is used to input a fluid disturbance into a flow for purpose of exciting a specific fluid instability mode.

40. The invention of claim 11, wherein the method is used in either a steady-state or a feed-back/feed-forward control scheme where the method is automatically or manually controlled to operate based on some feature of the flow.