An additional electrode ceramic channel structure for reducing wall energy loss

Abstract

This invention relates to a ceramic channel structure for reducing wall energy loss, belonging to the field of Hall thrusters. The invention addresses the problem of energy loss caused by a large number of ions bombarding the wall near the channel outlet during operation of existing Hall thrusters. The invention comprises: an annular ceramic channel with an upper opening; circumferential grooves are formed on the inner and outer annular walls at relative positions at the channel outlet; inner and outer additional metal electrodes are respectively embedded in the two circumferential grooves; each circumferential groove is connected to the outside through two symmetrical radial through holes; the inner electrode positive and negative conductive posts are respectively inserted into the two symmetrically arranged radial through holes on the inner ring and connected to the inner additional metal electrodes; the outer electrode positive and negative conductive posts are respectively inserted into the two symmetrically arranged radial through holes on the outer ring and connected to the outer additional metal electrodes.

Description

Technical Field

[0001] This invention relates to a ceramic channel structure for a Hall thruster, belonging to the field of Hall thrusters. Background Technology

[0002] Hall thrusters are currently the most widely used electric propulsion devices. They possess advantages such as simple structure, high reliability, high specific impulse, high efficiency, and long lifespan, making them suitable for high-precision on-orbit missions such as spacecraft attitude control, north-south position maintenance, and deep space exploration. Their working principle is as follows: a radial magnetic field is generated within the channel by an energized coil or permanent magnet, while an axial electric field is formed between the anode and cathode. Electrons emitted from the cathode move towards the anode under the influence of the orthogonal electromagnetic field, simultaneously ionizing atoms through collisions. The resulting ions are accelerated and ejected under the influence of the electric field, generating thrust.

[0003] Hall thrusters typically use ceramic materials for the channel walls. Due to the presence of the wall sheath, the potential at the center of the channel is higher than that at the wall surface, resulting in an electric field component perpendicular to the wall. This causes some of the ionized ions to collide with the wall surface under the influence of the radial electric field component, thus resulting in energy loss. Summary of the Invention

[0004] To address the problem of energy loss caused by a large number of ions bombarding the wall near the channel outlet during the operation of existing Hall thrusters, this invention provides an additional electrode ceramic channel structure to reduce wall energy loss.

[0005] The present invention discloses an additional electrode ceramic channel structure for reducing wall energy loss. An additional metal electrode is provided at the ceramic channel outlet, and a positive electric field pointing towards the channel is formed near the additional metal electrode. The positive electric field pointing towards the channel is used to suppress the electric field of ions moving towards the wall.

[0006] Preferably, an auxiliary electrode ceramic channel structure for reducing wall energy loss includes a ceramic channel 1, an inner ring auxiliary metal electrode 2, an outer ring auxiliary metal electrode 3, an inner electrode positive conductive pillar 4, an inner electrode negative conductive pillar 5, an outer electrode positive conductive pillar 6, and an outer electrode negative conductive pillar 7.

[0007] The ceramic channel 1 is an annular channel with an upper opening. Circumferential grooves are respectively opened on the inner and outer annular walls at the channel outlet. The inner ring additional metal electrode 2 and the outer ring additional metal electrode 3 are respectively embedded in the two circumferential grooves.

[0008] Each circumferential groove is connected to the outside through two symmetrical radial through holes;

[0009] The inner electrode positive conductive post 4 and the inner electrode negative conductive post 5 are respectively inserted into two radially through holes symmetrically arranged on the inner ring and connected to the inner ring additional metal electrode 2.

[0010] The positive conductive post 6 and the negative conductive post 7 of the outer electrode are respectively inserted into two radially through holes symmetrically arranged on the outer ring and connected to the additional metal electrode 3 of the outer ring.

[0011] Preferably, the ceramic channel 1 is made of ceramic material.

[0012] Preferably, the ceramic channel 1 is integrally formed using 3D ceramic printing technology.

[0013] Preferably, the inner ring additional metal electrode 2, the outer ring additional metal electrode 3, the inner electrode positive conductive post 4, the inner electrode negative conductive post 5, the outer electrode positive conductive post 6, and the outer electrode negative conductive post 7 are made of molybdenum.

[0014] Preferably, the inner electrode positive conductive post 4 and the inner electrode negative conductive post 5 are connected to the inner ring additional metal electrode 2 by welding, and the outer electrode positive conductive post 6 and the outer electrode negative conductive post 7 are connected to the outer ring additional metal electrode 3 by welding.

[0015] Preferably, the inner electrode positive conductive post 4 and the outer electrode positive conductive post 6 are connected to the power supply anode of the Hall thruster, and the inner electrode negative conductive post 5 and the outer electrode negative conductive post 7 are connected to the power supply negative electrode of the Hall thruster.

[0016] The beneficial effects of this invention are as follows: This invention adds a metal electrode at the channel outlet through structural design, and provides a fixed positive potential to the additional electrode through a conductive pillar. An electric field is formed at the wall position to suppress the movement of ions towards the wall, which effectively reduces the bombardment of ions on the channel outlet wall, reduces wall energy loss, and better improves the efficiency of the thruster. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural schematic diagram of an auxiliary electrode ceramic channel structure for reducing wall energy loss according to the present invention;

[0018] Figure 2 yes Figure 1 A schematic diagram of a half-section three-dimensional structure;

[0019] Figure 3 This is a three-dimensional structural diagram showing the connection relationship between the additional metal electrodes and conductive pillars.

[0020] Figure 4 yes Figure 1 A schematic diagram of a semi-sectional three-dimensional structure, in which an anode is installed at the bottom of the channel;

[0021] Figure 5 yes Figure 4 sectional plan view;

[0022] Figure 6This is a comparison of the radial electric field at the channel outlet under the additional electrode ceramic channel structure and the pure ceramic wall structure in Example 1;

[0023] Figure 7 This is a comparison of the ion flux through the inner wall of the channel under the additional electrode ceramic channel structure and the pure ceramic wall structure in Example 1;

[0024] Figure 8 This is a comparison of the ion flux on the outer wall of the channel under the additional electrode ceramic channel structure and the pure ceramic wall structure in Example 1;

[0025] Reference numerals: 1. Ceramic channel; 2. Inner ring additional metal electrode; 3. Outer ring additional metal electrode; 4. Inner electrode positive conductive post; 5. Inner electrode negative conductive post; 6. Outer electrode positive conductive post; 7. Outer electrode negative conductive post; 8. Anode; 9. Anode conductive post. Detailed Implementation

[0026] 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 some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0029] Specific Implementation Method 1: The following is combined with... Figures 1 to 8 This embodiment describes an additional electrode ceramic channel structure for reducing wall energy loss. An additional metal electrode is provided at the ceramic channel outlet, and a positive electric field pointing towards the channel is formed near the additional metal electrode. This positive electric field pointing towards the channel is used to suppress the movement of ions towards the wall.

[0030] An auxiliary electrode ceramic channel structure for reducing wall energy loss includes a ceramic channel 1, an inner ring auxiliary metal electrode 2, an outer ring auxiliary metal electrode 3, an inner electrode positive conductive pillar 4, an inner electrode negative conductive pillar 5, an outer electrode positive conductive pillar 6, and an outer electrode negative conductive pillar 7.

[0031] The ceramic channel 1 is an annular channel with an upper opening. Circumferential grooves are respectively opened on the inner and outer annular walls at the channel outlet. The inner ring additional metal electrode 2 and the outer ring additional metal electrode 3 are respectively embedded in the two circumferential grooves.

[0032] Each circumferential groove is connected to the outside through two symmetrical radial through holes;

[0033] The inner electrode positive conductive post 4 and the inner electrode negative conductive post 5 are respectively inserted into two radially through holes symmetrically arranged on the inner ring and connected to the inner ring additional metal electrode 2.

[0034] The positive conductive post 6 and the negative conductive post 7 of the outer electrode are respectively inserted into two radially through holes symmetrically arranged on the outer ring and connected to the additional metal electrode 3 of the outer ring.

[0035] Ceramic channel 1 is made of ceramic material.

[0036] The ceramic channel 1 is integrally formed using 3D ceramic printing technology, and then its dimensions are precisely finished by machining.

[0037] The inner ring additional metal electrode 2, the outer ring additional metal electrode 3, the inner electrode positive conductive post 4, the inner electrode negative conductive post 5, the outer electrode positive conductive post 6, and the outer electrode negative conductive post 7 are made of molybdenum.

[0038] The inner electrode positive conductive post 4 and the inner electrode negative conductive post 5 are connected to the inner ring additional metal electrode 2 by welding, and the outer electrode positive conductive post 6 and the outer electrode negative conductive post 7 are connected to the outer ring additional metal electrode 3 by welding.

[0039] The inner electrode positive conductive post 4 and the outer electrode positive conductive post 6 are connected to the power supply anode of the Hall thruster, and the inner electrode negative conductive post 5 and the outer electrode negative conductive post 7 are connected to the power supply negative terminal of the Hall thruster.

[0040] See Figure 4 The anode 8 is installed at the bottom of the ceramic channel 1 and is connected to an external power source through the anode conductive post 9. The anode 8 is responsible for providing the anode voltage required for the thruster to work.

[0041] Working process: The inner positive conductive post 4 and the outer positive conductive post 6 are connected to the power supply anode of the Hall thruster, while the inner negative conductive post 5 and the outer negative conductive post 7 are connected to the power supply negative terminal of the Hall thruster. Energizing the inner positive conductive post 4 and the outer positive conductive post 6 provides a positive potential to the inner ring auxiliary metal electrode 2 and the outer ring auxiliary metal electrode 3, creating a positive electric field pointing towards the channel near the auxiliary metal electrodes. This electric field reduces ion collisions with the wall surface. When electrons and ions collide with the auxiliary electrodes, current flows through the inner negative conductive post 5 and the outer negative conductive post 7, forming a circuit.

[0042] The following examples further illustrate the difference in wall energy loss between an additional electrode channel structure that reduces wall energy loss and a pure ceramic wall.

[0043] Example 1: Using the standard dimensions of the widely used SPT-100 Hall thruster, with an inner channel diameter of 36mm, an outer diameter of 50mm, and an axial length of 20mm, a structural model of the discharge channel was used to simulate the thruster's discharge process. The pure ceramic wall surface was BN ceramic. The additional electrode structure was installed at 16-19mm of the channel length, with a total length of 3mm. Molybdenum was selected as the additional metal electrode, and the ceramic wall structure was BN ceramic. Under the conditions of an anode voltage of 900V and a krypton flow rate of 40sccm, the radial potential distribution at the channel outlet is as follows: Figure 6 As shown, under pure ceramic wall conditions, the potential differences between the inner and outer wall surfaces and the channel center are -17.1V and 5.5V, respectively. Under conditions with an additional metal electrode, the potential differences between the inner and outer wall surfaces and the channel center are 80.1V and 83.8V, respectively. Clearly, the addition of a metal electrode effectively increases the potential difference between the wall surface and the channel center, which effectively reduces ion impacts on the wall surface, thereby reducing energy loss at the wall surface.

[0044] The statistical results of ion flux on the inner and outer walls of the channel are as follows: Figure 7 and Figure 8 As shown. Under pure ceramic wall conditions, the peak ion flux on both the inner and outer wall surfaces is 2.15 × 10⁻⁶. 21 / m 2 ·s and 1.75×10 21 / m 2 With the addition of a metal electrode, the peak ion flux at the inner and outer wall surfaces is 3.8 × 10⁻⁶ s. 20 / m 2 ·s and 4.04×10 20 / m 2 Under the condition of a metal-added electrode, the ion flux on the inner and outer wall surfaces is significantly reduced. Therefore, the metal-added electrode wall structure of this invention can effectively reduce ion bombardment of the wall surface, thereby reducing wall energy loss.

[0045] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. An auxiliary electrode ceramic channel structure for reducing wall energy loss, characterized in that, An additional metal electrode is provided at the ceramic channel outlet, and a positive electric field pointing towards the channel is formed near the additional metal electrode. The positive electric field pointing towards the channel is used to suppress the movement of ions towards the wall. It includes a ceramic channel (1), an inner ring additional metal electrode (2), an outer ring additional metal electrode (3), an inner electrode positive conductive post (4), an inner electrode negative conductive post (5), an outer electrode positive conductive post (6) and an outer electrode negative conductive post (7). The ceramic channel (1) is an annular channel with an upper opening. Circumferential grooves are opened on the inner and outer annular walls at the channel outlet, respectively. The inner ring additional metal electrode (2) and the outer ring additional metal electrode (3) are respectively embedded in the two circumferential grooves. Each circumferential groove is connected to the outside through two symmetrical radial through holes; The positive conductive post (4) and the negative conductive post (5) of the inner electrode are respectively inserted into two radial through holes symmetrically arranged on the inner ring and connected to the additional metal electrode (2) of the inner ring; The positive conductive post (6) and the negative conductive post (7) of the outer electrode are respectively inserted into two radial through holes symmetrically arranged on the outer ring and connected to the additional metal electrode (3) of the outer ring.

2. The auxiliary electrode ceramic channel structure for reducing wall energy loss according to claim 1, characterized in that, The ceramic channel (1) is made of ceramic material.

3. The auxiliary electrode ceramic channel structure for reducing wall energy loss according to claim 1, characterized in that, The ceramic channel (1) is integrally formed using 3D ceramic printing technology.

4. The auxiliary electrode ceramic channel structure for reducing wall energy loss according to claim 1, characterized in that, The inner ring additional metal electrode (2), the outer ring additional metal electrode (3), the inner electrode positive conductive post (4), the inner electrode negative conductive post (5), the outer electrode positive conductive post (6) and the outer electrode negative conductive post (7) are made of molybdenum.

5. The auxiliary electrode ceramic channel structure for reducing wall energy loss according to claim 1, characterized in that, The inner electrode positive conductive post (4) and the inner electrode negative conductive post (5) are connected to the inner ring additional metal electrode (2) by welding, and the outer electrode positive conductive post (6) and the outer electrode negative conductive post (7) are connected to the outer ring additional metal electrode (3) by welding.

6. The auxiliary electrode ceramic channel structure for reducing wall energy loss according to claim 1, characterized in that, The inner electrode positive conductive post (4) and the outer electrode positive conductive post (6) are connected to the power supply anode of the Hall thruster, and the inner electrode negative conductive post (5) and the outer electrode negative conductive post (7) are connected to the power supply negative electrode of the Hall thruster.

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