Dielectric barrier discharge device
The dielectric barrier discharge device with a ring-shaped electrode and gas inlet, optionally with magnetic or electrostatic grids, addresses plasma generation inefficiencies by enhancing plasma density and ion flow, improving performance in applications like aerodynamic actuators and ozone generators.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-05-01
- Publication Date
- 2026-04-09
AI Technical Summary
Existing dielectric barrier discharge devices face limitations in plasma generation efficiency and practicality, particularly in miniaturized applications, due to suboptimal electrode configurations and gas flow management.
A dielectric barrier discharge device with a ring-shaped first electrode surrounding a cavity, a second electrode opposite the cavity, and a gas inlet, combined with optional magnetic or electrostatic grids, enhances plasma generation and ion flow by focusing and accelerating plasma discharge.
The proposed configuration increases plasma density, ionization efficiency, and thermal energy transfer, improving performance in applications such as aerodynamic actuators and ozone generators.
Smart Images
Figure 2026062442000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the configuration of a dielectric barrier discharge device.
Background Art
[0002] A dielectric barrier discharge (DBD) device includes two electrodes, one of which is covered with a dielectric barrier material. These electrodes are connected to an AC power source that drives a discharge in the gap between the electrodes. The discharge causes ionization of the gas every half cycle of the electricity. The resulting plasma interacts with the surrounding air or other gas medium to induce a net flow called an ion wind or an electric wind. DBD devices are used, for example, as ozone generators, ultraviolet lamps, plasma generators, and aerodynamic flow control devices.
Summary of the Invention
Problems to be Solved by the Invention
[0003] Therefore, an object of the present invention is to provide a dielectric barrier discharge device of the type described at the beginning.
Means for Solving the Problems
[0004] A dielectric barrier discharge device according to an example of the present disclosure includes a dielectric layer having opposing first and second surfaces, a first electrode provided on the first surface and defining a ring surrounding a cavity, a second electrode provided on the second surface, a gas inlet connected to the cavity, and a power source electrically connected to the electrodes. The dielectric layer has a surface exposed at a first end of the cavity.
[0005] Another example of a dielectric barrier discharge apparatus according to the present disclosure comprises a dielectric layer having opposing first and second surfaces, and a first electrode provided on the first surface of the dielectric layer. The first electrode defines an array of cavities, and the dielectric layer has a surface exposed to the first ends of these cavities. The second electrode is positioned on a second side of the dielectric layer opposite to the cavities and is provided with a gas inlet that is fluidly connected to these cavities. A power supply is electrically connected to the first and second electrodes.
[0006] This disclosure may include one or more of the individual features disclosed above and / or below, either individually or in any combination.
[0007] Various features and advantages of this disclosure will become apparent to those skilled in the art from the following detailed description. In this disclosure, the same reference numeral indicates the same element where appropriate, and reference numerals that are multiples of 100 indicate modified elements that are understood to have the same features and advantages as the corresponding element. The drawings accompanying the detailed description can be briefly described below. [Brief explanation of the drawing]
[0008] [Figure 1] This is a diagram showing a dielectric barrier discharge device. [Figure 2] This figure shows a further example of a dielectric barrier discharge device having a magnetic ring. [Figure 3A] This is a cross-sectional view of an array-type dielectric barrier discharge device. [Figure 3B] This is a top view of an array-type dielectric barrier discharge device. [Figure 4A] This is a cross-sectional view of another array-type dielectric barrier discharge device. [Figure 4B] This is a top view of an array-type dielectric barrier discharge device. [Modes for carrying out the invention]
[0009] Figure 1 shows a dielectric barrier discharge device 20. In this example, device 20 is used in a thruster 22. Devices in the examples described later are also used in thrusters. These devices are not limited to these applications and can be used in many other applications, including but not limited to synthetic jet actuators for boundary layer control, ozone generators, ultraviolet lamps, and plasma generators.
[0010] The apparatus 20 includes a dielectric layer 24 having opposing first surfaces 24a and second surfaces 24b. For example, the dielectric layer 24 is made of a solid dielectric material, which is an electrical insulator that polarizes due to the movement of positive and negative charges and net displacement when an electric field is applied. Many ceramics, mica, and quartz glass are considered dielectric materials. Other examples of dielectric materials include, but are not limited to, aluminum nitride, boron nitride, alumina, and borosilicates.
[0011] A first electrode 26 is provided on the first surface 24a of the dielectric layer 24. The first electrode 26 is ring-shaped and surrounds the cavity 26a. In the illustrated example, the ring is annular and the cavity is cylindrical. For example, the diameter of the cavity 26a is at least 2 millimeters, e.g., 5 millimeters, but may be 20 millimeters or more. An electrode 26 with a cavity 26a of less than 2 millimeters functions as a continuous plate and therefore cannot achieve the desired effect of generating plasma, while a significantly larger size may limit the power and is not practical. Furthermore, for miniaturization and field generation, the cavity 26a has a height (h), and the aspect ratio of the diameter to the height of the cavity 26a is greater than 1.
[0012] The cavity 26a extends in the thickness direction of the first electrode 26, and the dielectric layer 24 has a surface 24c exposed at the first end 28a of the cavity 26a. On the second surface 24b of the dielectric layer 24, the second electrode 30 is positioned opposite the cavity 26a. In some examples, the second electrode 30 is housed within the dielectric layer 24. A fluid-connected gas inlet 32 is present in the cavity 26a to supply a working gas such as air, argon, or hydrazine to the apparatus 20. All apparatuses described herein are usable with various gases, which further enables multimode operation of the apparatus across a wide range of applications.
[0013] Power supply 34 is electrically connected to electrodes 26 / 30. For example, power supply 34 is an AC power supply, but power supply 34 may also have a DC bias. When power supply 34 is operating, it generates plasma in the cavity 26a from the working gas supplied from the gas inlet 32. As indicated by arrow 38, the plasma is discharged from the second open end 28b of the cavity 26, opposite the first end 28a.
[0014] Figure 2 shows a cross-sectional view of a selected portion of a further example of the apparatus 20, cut along a plane containing the central axis of the cylindrical cavity 26a. In this example, the apparatus 20 further includes a magnetic ring 36 on the first electrode 26. The magnetic ring 36 is aligned with and circumscribing the second end 28b of the cavity 26. In this example, the magnetic ring 36 is a permanent magnet, but it should be noted that an electromagnet may also be used. The magnetic ring 36 provides a magnetic field that accelerates the plasma discharged from the second end 28b. The cylindrical cavity 26 and magnetic ring 36 promote the focusing of the plasma discharge, increasing the likelihood of ionization collisions, increasing plasma density, and extending residence time compared to a linear dielectric barrier discharge apparatus. The plasma focusing also increases thermal energy transfer and momentum transfer to local neutral particles, which can improve performance as an aerodynamic actuator and ozone generator. For example, the electron velocity vector is in the azimuthal direction (Hall current), which promotes magnetic confinement of ionizing electrons and increases the degree of ionization.
[0015] Figure 3A shows a cross-sectional view of a selected portion of a dielectric barrier discharge apparatus 120 in another example, and Figure 3B shows a top view looking down on the apparatus 120. Conceptually, the apparatus 120 integrates multiple apparatuses 20 into an array configuration with an electrostatic grid 136. This array configuration can increase plasma generation and ion flow, and as a result enhance the impact on electric propulsion thrust generation, ozone generation, or aerofoil boundary layer control.
[0016] For example, the first electrode 26 includes a plurality of cavities 26a arranged in a row-and-column array grid pattern, and the electrostatic grid 136 is provided on the cavities 26a. An insulating layer 37 is present between the grid 136 and the first electrode 26 to maintain electrical insulation. The electrostatic grid 136 includes an array of a plurality of openings 136a superimposed on a plurality of exit ends 28b. Similar to the magnet 36, the grid 136 plays a role in accelerating the plasma from the cavities 26a.
[0017] Figure 4A shows a cross-sectional view of a selected portion of a dielectric barrier discharge apparatus 220 in another example, and Figure 4B shows a top view looking down on the apparatus 220. Similar to apparatus 120, apparatus 220 integrates multiple apparatuses 20 into an array configuration with an electrostatic grid 236. The electrostatic grid 236 is supplied with a DC bias. For example, the first electrode 26 includes multiple cavities 26a arranged in a row-and-column arrangement, and the electrostatic grid 236 is provided on the cavities 26a. An insulating layer 137 is present between the grid 236 and the first electrode 26 to maintain electrical insulation. The electrostatic grid 236 includes an array of multiple openings 236a superimposed on multiple outlet ends 28b. Similar to the magnet 36, the grid 236 plays a role in accelerating the plasma from the cavities 26a. Furthermore, in this example, one or more gas inlets 32 are provided in the insulating layer 137 to supply propellant working gas through apparatus 220. In this example, the offset rows provide a higher density of cavities 26a and openings 236a per unit area.
[0018] While the illustrated examples show combinations of features, it is not necessary to combine all of them to realize the advantages of the various embodiments of this disclosure. In other words, a system designed according to the embodiments of this disclosure does not necessarily include all of the features shown in any of the figures, or all of the parts schematically shown in the figures. Furthermore, selected features from one embodiment may be combined with selected features from another embodiment.
[0019] The above description is illustrative and not limiting in nature. It will be apparent to those skilled in the art that variations and modifications to the disclosed examples will not necessarily deviate from this disclosure. The scope of legal protection granted in this disclosure can only be determined by considering the following claims.
Claims
1. A dielectric layer having opposing first and second surfaces, A first electrode provided on the first surface of the dielectric layer, the first electrode defining a ring surrounding the cavity, and having a surface on which the dielectric layer is exposed at the first end of the cavity, A second electrode provided on the second surface of the dielectric layer opposite to the cavity, A gas inlet fluidly connected to the cavity, A power supply electrically connected to the first electrode and the second electrode, A dielectric barrier discharge device equipped with the following features.
2. The dielectric barrier discharge apparatus according to claim 1, characterized in that, when the power supply is in operation, it generates plasma from the gas flowing into the cavity from the gas inlet, and the plasma is discharged from the second open end of the cavity opposite to the first end.
3. The dielectric barrier discharge apparatus according to claim 1, further comprising a magnetic ring on the first electrode surrounding the second end of the cavity, wherein the magnetic ring accelerates the plasma discharged from the second end.
4. The dielectric barrier discharge apparatus according to claim 3, further comprising an insulating layer between the magnetic ring and the first electrode.
5. The dielectric barrier discharge apparatus according to claim 1, characterized in that the cavity is cylindrical and has a diameter of at least 2 millimeters.
6. The dielectric barrier discharge apparatus according to claim 1, characterized in that the cavity has height and the aspect ratio of the diameter to the height is greater than 1.
7. A dielectric layer having opposing first and second surfaces, A first electrode provided on the first surface of the dielectric layer, the first electrode defining an array of multiple cavities, and the dielectric layer having a surface exposed at the first end of the cavity, A second electrode provided on the second surface of the dielectric layer opposite to the cavity, A gas inlet fluidly connected to the cavity, A power supply electrically connected to the first electrode and the second electrode, A dielectric barrier discharge device equipped with the following features.
8. The dielectric barrier discharge apparatus according to claim 7, characterized in that, when the power supply is in operation, it generates plasma from the gas flowing into the cavity from the gas inlet, and the plasma is discharged from the second open end of the cavity opposite to the first end.
9. The dielectric barrier discharge apparatus according to claim 7, characterized in that the array has a grid pattern.
10. The dielectric barrier discharge apparatus according to claim 7, characterized in that the gas inlet is provided in the insulating layer.
11. The dielectric barrier discharge apparatus according to claim 7, characterized in that each of the cavities is cylindrical and has a diameter of at least 2 millimeters.
12. The dielectric barrier discharge device according to claim 7, characterized in that the dielectric barrier discharge device is provided inside a thruster.