A multi-frequency excited three-electrode plasma igniter

Abstract

This invention discloses a multi-frequency excited three-electrode plasma igniter, relating to the field of aero-engine technology. The igniter includes an ignition cylinder, an electrode assembly, and a power supply assembly. The ignition cylinder has an air inlet, a discharge chamber, and a jet outlet connected sequentially. The electrode assembly includes a first electrode, a second electrode, and a third electrode. The first electrode is fixed within the discharge chamber and has an insulating component. The second electrode is disposed on the insulating component, and the third electrode forms part of the cylinder wall of the ignition cylinder and forms the jet outlet. The power supply assembly includes a first power supply and a second power supply. The first output terminal of the first power supply is electrically connected to the first electrode, the second output terminal of the first power supply is electrically connected to the third electrode, the positive output terminal of the second power supply is electrically connected to the second electrode, and the negative output terminal of the second power supply is electrically connected to the third electrode. Under the excitation mode of the multi-frequency power supply, the igniter of this invention can enhance the ignition efficiency of the high-temperature jet and broaden the ignition boundary.

Description

Technical Field

[0001] This invention relates to the field of aero-engine ignition system technology, and in particular to a multi-frequency excited three-electrode plasma igniter. Background Technology

[0002] Plasma ignition involves discharging a gaseous working fluid introduced into a plasma igniter to generate a high-temperature, high-speed plasma jet, which simultaneously excites a large number of active particles. This high-temperature, high-speed jet is injected into the combustion chamber, where the fuel and air mix, resulting in deep penetration of the flame core and a large number of active particles participating in combustion, effectively enhancing the ignition effect within the combustion chamber.

[0003] Plasma ignition technology, as a novel ignition technology, has been studied in fields such as internal combustion engines, aero engines, pulse detonation engines, and scramjet engines, and has already been commercially applied in some areas.

[0004] Currently, most plasma igniters employ a single positive and negative electrode pair and a single power source. In one exemplary technology, an aero-engine air swirling plasma igniter includes components such as a housing, inlet pipe, anode sleeve, insulating sleeve, cathode mount, support sleeve, cathode, and swirler. However, this igniter exhibits low ignition efficiency for high-temperature jets and a narrow ignition boundary. When external operating conditions change rapidly and drastically, this single-power-source-excited ignition method may experience reduced adaptability. Summary of the Invention

[0005] The main objective of this invention is to provide a multi-frequency excited three-electrode plasma igniter, which aims to enhance the ignition efficiency of high-temperature jets and broaden the ignition boundary.

[0006] To achieve the above objectives, this invention proposes a multi-frequency excited three-electrode plasma igniter, the igniter comprising:

[0007] The ignition cylinder has an air inlet, a discharge chamber, and a jet inlet connected in sequence.

[0008] An electrode assembly includes a first electrode, a second electrode, and a third electrode. The first electrode is fixed within the discharge cavity and has an insulating component. The second electrode is disposed on the insulating component. The third electrode forms part of the ignition cylinder wall and constitutes the jet orifice.

[0009] A power supply assembly includes a first power supply and a second power supply. The first power supply has a first output terminal and a second output terminal. The first output terminal of the first power supply is electrically connected to a first electrode, and the second output terminal of the first power supply is electrically connected to a third electrode. The positive output terminal of the second power supply is electrically connected to the second electrode, and the negative output terminal of the second power supply is electrically connected to the third electrode.

[0010] Optionally, the first power source and the second power source are plasma excitation power sources of different frequencies, used to sequentially or simultaneously generate plasma discharge channels between the first electrode and the third electrode and between the second electrode and the third electrode.

[0011] Optionally, the first power supply is an AC power supply, the frequency of the first power supply is above 10kHz, the output voltage of the first power supply is above 2kV, and the output waveform of the first power supply is a square wave, a sine wave, a trapezoidal wave, or a triangular wave.

[0012] Optionally, the second power supply is a pulse power supply, the voltage of the second power supply is above 5kV, the pulse width of the second power supply is above 50ns, and the repetition frequency of the second power supply is above 500Hz.

[0013] Optionally, the third electrode is made of stainless steel, has an inner diameter of 14 mm, a wall thickness of 4 mm, and is provided with a nozzle portion forming the jet orifice. The bevel taper of the nozzle portion is 45°, and the orifice diameter of the jet orifice is 3 mm.

[0014] Optionally, the ignition cylinder includes a conductive support, an insulating support, and an insulating connecting cylinder. The conductive support is sleeved on the end of the first electrode and electrically connected to the first power source. One end of the insulating support is connected to the conductive support and sleeved on the end of the insulating member. The other end of the insulating support is connected to the second electrode. The second electrode and the third electrode are connected through the insulating connecting cylinder. The conductive support, the insulating support, the second electrode, the insulating connecting cylinder, and the third electrode together constitute the discharge cavity.

[0015] Optionally, the conductive support is provided with an air inlet pipe support, and an air inlet pipe forming the air inlet is sleeved on the air inlet pipe support.

[0016] Optionally, the insulating support member is provided with a plurality of through holes evenly distributed along its circumference to ensure gas flow.

[0017] Optionally, both the first electrode and the second electrode are made of high-temperature resistant and ablation-resistant metallic materials.

[0018] Optionally, the air inlet is adapted to allow the introduction of dry gas.

[0019] In the technical solution of this invention, the igniter includes an ignition cylinder, an electrode assembly, and a power supply assembly. The ignition cylinder has an air inlet, a discharge chamber, and a jet outlet connected in sequence. The electrode assembly includes a first electrode, a second electrode, and a third electrode. The first electrode is fixed inside the discharge chamber and has an insulating component. The second electrode is disposed on the insulating component, and the third electrode forms part of the cylinder wall of the ignition cylinder and forms the jet outlet. The power supply assembly includes a first power supply and a second power supply. The first output terminal of the first power supply is electrically connected to the first electrode, the second output terminal of the first power supply is electrically connected to the third electrode, the positive output terminal of the second power supply is electrically connected to the second electrode, and the negative output terminal of the second power supply is electrically connected to the third electrode. Thus, through a composite excitation mode, the active particles inside the plasma igniter can be effectively increased, while the plasma discharge voltage of the second pair of positive and negative electrodes can be reduced. This results in an increase in the injection current of the plasma channel under the same input power, raising the temperature of the high-temperature jet and widening the reignition boundary of the aero-engine. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0021] Figure 1 This is a cross-sectional view of an embodiment of the multi-frequency excited three-electrode plasma igniter of the present invention;

[0022] Figure 2 This is a cross-sectional view of the first electrode in one embodiment of the multi-frequency excited three-electrode plasma igniter of the present invention;

[0023] Figure 3 This is a cross-sectional view of the second electrode in one embodiment of the multi-frequency excited three-electrode plasma igniter of the present invention;

[0024] Figure 4 This is a cross-sectional view of the insulating support member in one embodiment of the multi-frequency excited three-electrode plasma igniter of the present invention.

[0025] Explanation of icon numbers:

[0026] 10. Ignition cylinder body; 20. Electrode assembly; 30. Power supply assembly; 10a. Air inlet; 10b. Discharge chamber; 10c. Jet port; 21. First electrode; 22. Second electrode; 23. Third electrode; 24. Insulating component; 31. First power supply; 32. Second power supply; 11. Conductive support component; 12. Insulating support component; 13. Insulating connecting cylinder; 14. Air inlet pipe support component; 15. Air inlet pipe; 12a. Through hole.

[0027] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0030] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, if the word "and / or" appears throughout the text, it means including three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0031] This invention proposes a multi-frequency excited three-electrode plasma igniter, which can be applied to aero engines, internal combustion engines, pulse detonation engines, scramjet engines, etc., and is not limited to these applications.

[0032] Reference Figure 1In one embodiment of the present invention, the multi-frequency excited three-electrode plasma igniter includes an ignition cylinder 10, an electrode assembly 20, and a power supply assembly 30. The ignition cylinder 10 has an air inlet 10a, a discharge chamber 10b, and a jet outlet 10c connected in sequence. The electrode assembly 20 includes a first electrode 21, a second electrode 22, and a third electrode 23. The first electrode 21 is fixed in the discharge chamber 10b and has an insulating member 24. The second electrode 22 is disposed on the insulating member 24. The third electrode 23 forms part of the cylinder wall of the ignition cylinder 10 and forms the jet outlet 10c. The power supply assembly 30 includes a first power supply 31 and a second power supply 32. The first power supply 31 has a first output terminal and a second output terminal. The first output terminal of the first power supply 31 is electrically connected to the first electrode 21, and the second output terminal of the first power supply 31 is electrically connected to the third electrode 23. The positive output terminal of the second power supply 32 is electrically connected to the second electrode 22, and the negative output terminal of the second power supply 32 is electrically connected to the third electrode 23.

[0033] In this embodiment, the ignition cylinder 10 can be assembled from multiple cylindrical components, and the third electrode 23 can also be configured as a cylindrical structure to form part of the cylinder wall of the ignition cylinder 10 and form a jet port 10c for spraying high-temperature jets.

[0034] In this embodiment, the first electrode 21 and the second electrode 22 can both be high-voltage electrodes, and the third electrode 23 can be a low-voltage common electrode. The first electrode 21 and the second electrode 22 can both be made of high-temperature resistant and ablation-resistant metal materials, especially tungsten copper alloy materials, and their outer diameter can both be set to about 6mm. The third electrode 23 can be made of stainless steel or other metal materials, which is not limited here.

[0035] The first power supply 31 and the second power supply 32 are plasma excitation power supplies of different frequencies, used to generate plasma discharge channels sequentially or simultaneously between the first electrode 21 and the third electrode 23 and between the second electrode 22 and the third electrode 23.

[0036] It is understood that the present invention can effectively increase the active particles inside the plasma igniter through a composite excitation mode, while reducing the plasma discharge voltage of the second pair of positive and negative electrodes. This results in an increase in the injection current of the plasma channel under the same input power, which in turn increases the temperature of the high-temperature jet and broadens the re-ignition boundary of the aero-engine.

[0037] It should be noted that the igniter generates a high-temperature jet by discharging plasma onto a flowing gas, and its inlet 10a is suitable for introducing dry gas, including but not limited to air, nitrogen or helium.

[0038] To further enhance the ignition efficiency of the high-temperature jet and broaden the ignition boundary, the main references are as follows: Figure 1In one embodiment, the first power supply 31 can be an AC power supply, the frequency of the first power supply 31 can be 10kHz or higher, the output voltage of the first power supply 31 can be 2kV or higher, and the output waveform of the first power supply 31 can be a square wave, sine wave, trapezoidal wave or triangular wave, etc.; the second power supply 32 can be a pulse power supply, the voltage of the second power supply 32 can be 5kV or higher, the pulse width of the second power supply 32 can be 50ns or higher, and the repetition frequency of the second power supply 32 can be 500Hz or higher, which is not limited here.

[0039] Preferably, the first power supply 31 adopts a high-frequency high-voltage AC power supply with an output voltage of about 5000V and a frequency of 20kHz, and its waveform is approximately a sine wave; the second power supply 32 adopts a high-voltage pulse power supply with an output voltage of about 15000V, a pulse width of 100ns, and a frequency of 1kHz.

[0040] Main reference Figure 1 In one embodiment, the third electrode 23 is made of stainless steel, particularly 304 stainless steel. The inner diameter of the third electrode 23 can be 14 mm, the wall thickness of the third electrode 23 can be 4 mm, and the third electrode 23 is provided with a nozzle portion forming a jet orifice 10c. The bevel taper of the nozzle portion can be 45°, and the orifice diameter of the jet orifice 10c can be 3 mm. This further improves the ignition performance of the igniter to adapt to different operating conditions.

[0041] To improve the ease of assembly of this igniter and ensure the insulation between the electrodes, refer to Figures 1 to 4 In one embodiment, the ignition cylinder 10 may include a conductive support 11, an insulating support 12, and an insulating connecting cylinder 13. The conductive support 11 is sleeved on the end of the first electrode 21 and electrically connected to the first power supply 31. One end of the insulating support 12 is connected to the conductive support 11 and is sleeved on the end of the insulating member 24. The other end of the insulating support 12 is connected to the second electrode 22. The second electrode 22 and the third electrode 23 are connected through the insulating connecting cylinder 13. The conductive support 11, the insulating support 12, the second electrode 22, the insulating connecting cylinder 13, and the third electrode 23 together constitute a discharge cavity 10b. The conductive support 11 is provided with an air inlet pipe support 14, and an air inlet pipe 15 forming an air inlet 10a is sleeved on the air inlet pipe support 14.

[0042] The multi-frequency excited three-electrode plasma igniter of the present invention adopts a coaxial structure design. During assembly, the conductive support 11 serves as the mounting base. The conductive support 11 can be connected to the insulating support 12 via a threaded connection structure. The second electrode 22 can also be connected to the insulating support 12 via a threaded connection. The insulating connecting cylinder 13 can be connected to the second electrode 22 via a threaded connection. After the first electrode 21 is fitted into the insulating component 24, it is then inserted into the center hole of the second electrode 22 and connected and tightened to the center threaded hole of the conductive support 11 via a threaded connection. The third electrode 23 can be connected to the insulating connecting cylinder 13 via a threaded connection. The intake pipe support 14 can be connected to the conductive support 11 via a threaded connection. The intake pipe 15 can be fitted onto the intake pipe support 14 and can be fixed to the outer wall of the intake pipe support 14 using a sealing and fastening method. One output terminal of the high-frequency high-voltage AC power supply is connected to the first electrode 21 via the conductive support 11, and the other output terminal of the high-frequency high-voltage AC power supply is connected to the third electrode 23. The positive output terminal of the high-voltage pulse power supply is connected to the second electrode 22, and the negative output terminal of the high-voltage pulse power supply is connected to the third electrode 23.

[0043] In this embodiment, the conductive support 11 and the air intake pipe support 14 can both be made of 304 stainless steel, and their inner diameter can be set to about 14mm and their wall thickness can be about 4mm. There are no restrictions here.

[0044] In this embodiment, the insulating member 24 between the first electrode 21 and the second electrode 22 can be made of ceramic, preferably 95 ceramic; the insulating support member 12 and the insulating connecting cylinder 13 can both be made of FR4, with an inner diameter of about 14 mm and a wall thickness of about 4 mm; the air intake pipe 15 can be made of rubber tubing or metal tubing with an inner diameter of 10 mm, etc., and is not limited here.

[0045] In addition, to ensure gas flow within the discharge cavity 10b, this embodiment mainly refers to... Figure 1 and Figure 4 The insulating support 12 is provided with a plurality of through holes 12a evenly distributed along its circumference to ensure gas flow.

[0046] In this embodiment, the through hole 12a includes, but is not limited to, a straight-through vent hole and a rotating vent hole.

[0047] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A multi-frequency excited three-electrode plasma igniter, characterized in that, The igniter includes: The ignition cylinder (10) has an air inlet (10a), a discharge chamber (10b) and a jet outlet (10c) connected in sequence. The electrode assembly (20) includes a first electrode (21), a second electrode (22), and a third electrode (23). The first electrode (21) is fixed inside the discharge chamber (10b). An insulating member (24) is provided on the first electrode (21). The second electrode (22) is disposed on the insulating member (24). The third electrode (23) constitutes part of the cylinder wall of the ignition cylinder (10) and forms the jet port (10c). The power supply assembly (30) includes a first power supply (31) and a second power supply (32). The first power supply (31) has a first output terminal and a second output terminal. The first output terminal of the first power supply (31) is electrically connected to the first electrode (21). The second output terminal of the first power supply (31) is electrically connected to the third electrode (23). The positive output terminal of the second power supply (32) is electrically connected to the second electrode (22). The negative output terminal of the second power supply (32) is electrically connected to the third electrode (23). The ignition cylinder (10) includes a conductive support (11), an insulating support (12), and an insulating connecting cylinder (13). The conductive support (11) is sleeved on the end of the first electrode (21) and electrically connected to the first power source (31). One end of the insulating support (12) is connected to the conductive support (11), and the insulating support (12) is sleeved on the end of the insulating member (24). The other end of the insulating support (12) is connected to the second electrode (22). The second electrode (22) and the third electrode (23) are connected through the insulating connecting cylinder (13). The conductive support (11), the insulating support (12), the second electrode (22), the insulating connecting cylinder (13), and the third electrode (23) together constitute the discharge cavity (10b). The insulating support (12) is provided with a plurality of through holes (12a) evenly distributed along its circumference to ensure gas flow.

2. The igniter as described in claim 1, characterized in that, The first power source (31) and the second power source (32) are plasma excitation power sources of different frequencies, used to generate plasma discharge channels between the first electrode (21) and the third electrode (23) and between the second electrode (22) and the third electrode (23) in sequence or simultaneously.

3. The igniter as described in claim 2, characterized in that, The first power supply (31) is an AC power supply, the frequency of the first power supply (31) is above 10kHz, the output voltage of the first power supply (31) is above 2kV, and the output waveform of the first power supply (31) is a square wave, a sine wave, a trapezoidal wave, or a triangular wave.

4. The igniter as described in claim 2, characterized in that, The second power supply (32) is a pulse power supply. The voltage of the second power supply (32) is above 5kV, the pulse width of the second power supply (32) is above 50ns, and the repetition frequency of the second power supply (32) is above 500Hz.

5. The igniter as described in claim 1, characterized in that, The material of the third electrode (23) is stainless steel. The inner diameter of the third electrode (23) is 14 mm, the wall thickness of the third electrode (23) is 4 mm, and the third electrode (23) is provided with a nozzle portion forming the jet orifice (10c). The bevel taper of the nozzle portion is 45°, and the aperture of the jet orifice (10c) is 3 mm.

6. The igniter as described in claim 1, characterized in that, The conductive support (11) is provided with an air inlet pipe support (14), and an air inlet pipe (15) forming the air inlet (10a) is sleeved on the air inlet pipe support (14).

7. The igniter as described in claim 1, characterized in that, Both the first electrode (21) and the second electrode (22) are made of metal materials that are resistant to high temperature and ablation.

8. The igniter as described in claim 1, characterized in that, The air inlet (10a) is adapted to allow the introduction of dry gas.

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