CN109751212B - Pulsed plasma thruster with microporous insulated anode - Google Patents

Abstract

The invention discloses a pulse plasma thruster with a micropore insulation anode, and relates to the technical field of microsatellite thrusters. The cathode is flat. The front end of the cathode is provided with a discharge end; the surface of the cathode is provided with a cubic insulating layer sleeve, and the inner surface of the insulating layer is in contact with the surface of the cathode; the anode is a cubic cylindrical structure fixed on the outer wall of the insulating layer, one end of the anode is made into a bell mouth shape, and the cubic end of the anode is contacted with the outer wall of the insulating layer; the surface of the anode is wrapped by an insulating material, and micropores are only arranged on the inner surface of the horn-shaped anode insulating layer; the non-discharge end of the cathode is electrically connected with an external circuit negative high-voltage terminal, and the anode is grounded. Under the condition of not influencing the generation of the plasma, the invention reduces the quantity of charged particles entering the anode, so that more plasma is sprayed out along the insulating sleeve to form thrust, and the efficiency of the pulse plasma thruster is improved.

Description

Pulsed plasma thruster with microporous insulated anode

technical field

The invention relates to the technical field of microsatellite thrusters, in particular to a pulsed plasma thruster with a microporous insulating anode.

Background technique

With the development of microsatellite technology, new requirements are put forward for its propulsion system, which requires it to achieve high specific impulse and high efficiency output. The electric propulsion system has gradually replaced the traditional chemical propulsion system due to its advantages in structure and function, and has become the main propulsion method of the microsatellite system. Due to its simple structure, light weight and high specific impulse, pulsed plasma thrusters have attracted more and more attention around the world.

Conventional pulsed plasma thrusters use a bare metal discharge electrode structure. However, most of the generated plasma enters the metal electrode under the action of an external electric field, forming a circuit current. Only a small part of the plasma is ejected from the electrode to form thrust. Therefore, based on the previous research, this paper proposes a pulsed plasma thruster with a microporous insulating anode. The existence of micropores does not affect the plasma generation, and reduces the number of charged particles entering the anode, allowing more charged particles to form a directional jet, improving the efficiency of the pulsed plasma thruster.

The literature "Tian Jia, Liu Wenzheng, Cui Weisheng, Gao Yongjie. Generation characteristics of a metalion plasma jet in vacuum discharge[J]. Plasma Science and Technology, 2018, 20: 1-7." proposed a fully insulated anode electrode structure, The passage of the charged particles generated by the discharge is hindered from moving to the electrode, so that more plasma is ejected along the insulating sleeve, and the density and propagation speed of the plasma source are increased. However, compared with the traditional bare metal anode electrode structure, the cathode current amplitude generated by the discharge with the fully insulated anode electrode structure is reduced. From the discharge phenomenon point of view, the plasma jet length does not increase significantly.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a flat-plate pulsed plasma thruster with a microporous insulating anode, which can improve the density and ejection speed of the plasma source without affecting the plasma generation, so as to solve the problems existing in the above-mentioned background technology. In the process of vacuum discharge, the density of the plasma source is not high and the energy is low.

In order to achieve the above object, the present invention has adopted the following technical solutions:

A pulsed plasma thruster with a microporous insulating anode, comprising a cathode, an insulating sleeve sleeved on the cathode, and an anode fixed sleeved on the front end of the insulating sleeve;

The front end of the cathode is provided with a discharge end, and the anode includes a straight cylinder portion and a horn opening portion;

The inner surface of the straight cylindrical portion is connected with the outer surface of the insulating sleeve; the part of the anode that is not in contact with the insulating sleeve is wrapped with an anode insulating layer;

Micro-holes are provided on the insulating layer on the inner surface of the horn opening;

The flat plate end of the cathode is electrically connected to the negative high-voltage terminal of the external circuit, and the anode is grounded.

Preferably, the cathode is plate-shaped.

Preferably, the discharge end is in the shape of a protrusion provided at the front end of the plate-shaped cathode.

Preferably, the flat plate end surface of the cathode is in contact with the inner wall of the insulating sleeve.

Preferably, the micro-hole is located at the geometric center of the insulating layer on the inner surface of the horn opening.

Preferably, the cathode is made of magnetic conductive metal material, and the discharge end is made of lead.

Preferably, the anode is made of copper material.

Preferably, the insulating sleeve is made of ceramic material.

Preferably, the anode insulating layer is made of Teflon material.

Preferably, the micropores are circular.

The beneficial effects of the invention are as follows: the plasma generated by the cathode is blocked and bound by the insulating sleeve, which improves the ability of directional spraying of the plasma; the inner surface of the anode is provided with micropores, and the existence of the micropores does not affect the plasma generation conditions, The number of charged particles entering the anode is reduced, so that more charged particles are ejected in a directional manner to form thrust, and the efficiency of the pulse plasma thruster is improved.

Additional aspects and advantages of the present invention will be set forth in part in the following description, which will be apparent from the following description, or may be learned by practice of the present invention.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

FIG. 1 is a structural diagram of a pulsed plasma thruster with a microporous insulating anode according to an embodiment of the present invention.

FIG. 2 is a discharge circuit diagram of a pulsed plasma thruster with a microporous insulating anode according to an embodiment of the present invention.

FIG. 3 is a structural diagram of a non-insulated anode plasma thruster without an anode insulating layer wrapped according to an embodiment of the present invention.

FIG. 4 is a structural diagram of the plasma thruster without microporous provided in the anode insulating layer according to the embodiment of the present invention.

FIG. 5 is a graph showing the distribution of plasma density generated by using a non-insulated anode and an insulated anode with micropores measured in an embodiment of the present invention.

FIG. 6 is a graph of the propagation velocity of plasma generated by using a non-insulated anode and an insulated anode with micropores measured in an embodiment of the present invention.

FIG. 7 is a graph showing the distribution of plasma density under different insulating micropores measured in an embodiment of the present invention.

FIG. 8 is a graph showing the distribution of plasma propagation velocity under different insulating micropores measured in an embodiment of the present invention.

Wherein: 1-cathode; 2-insulating sleeve; 3-anode; 31-straight cylinder part; 32-horn opening part; 4-anode insulating layer; 5-micropore; 6-discharge end.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below through the accompanying drawings are exemplary and are only used to explain the present invention, but not to be construed as a limitation of the present invention.

It will be understood by those skilled in the art that the singular forms "a", "an", "the" and "the" as used herein can include the plural forms as well, unless expressly stated otherwise. It should be further understood that the word "comprising" used in the description of the present invention refers to the presence of stated features, integers, steps, operations, elements and/or components, but does not exclude the presence or addition of one or more other features, Integers, steps, operations, elements and/or groups thereof. It should be understood that "connected" or "coupled" as used herein can include wirelessly connected or coupled, and that use of the term "and/or" includes any and all combinations of one or more of the associated listed items.

It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and, unless defined as herein, are not to be taken in an idealized or overly formal sense. explain.

In order to facilitate the understanding of the present invention, the present invention will be further explained and described below with reference to the accompanying drawings with specific embodiments, and the specific embodiments do not constitute limitations to the embodiments of the present invention.

Those skilled in the art should understand that the accompanying drawings are only schematic diagrams of the embodiments, and the components in the accompanying drawings are not necessarily necessary to implement the present invention.

Example

As shown in FIG. 1 , an embodiment of the present invention provides a pulsed plasma thruster with a microporous insulating anode, including a cathode 1 , an insulating sleeve 2 sleeved on the cathode, an anode 3 , and an anode insulating layer 4 and micropores 5, the cathode 1 is a flat plate, the front end of the cathode 1 is provided with a discharge end 6, the anode 3 is a cubic cylindrical structure fixedly sleeved on the outer wall of the insulating sleeve 2, the The front end of the anode 3 is shaped like a bell mouth to form a horn opening 32 , and the inner surface of the straight cylindrical portion 31 of the anode 3 is in contact with the outer surface of the insulating sleeve 2 . The surface of the anode 3 is wrapped by the anode insulating layer 4 , and only the inner surface of the insulating layer of the horn opening 32 is provided with micropores 5 .

The flat plate end of the cathode 1 is electrically connected to the negative high-voltage terminal of the external circuit, and the anode 3 is grounded.

The discharge end 6 is a protruding shape provided at the front end of the plate-shaped cathode 1 .

In practical applications, the shape of the discharge end 6 may be a shape with protrusions such as a wedge shape, an arc shape, a cube shape, and the like. The specific shape of the discharge end 6 is not limited by the above-mentioned shape, and its shape can be specifically set by those skilled in the art according to the actual situation.

The flat end surface of the cathode 1 is in contact with the inner wall of the insulating sleeve 2 .

The micro-hole 5 is located at the geometric center of the insulating layer 4 on the inner surface of the horn opening 32 .

The cathode 1 is made of magnetic conductive metal material, and the discharge end 6 is made of lead.

In practical applications, the discharge terminal 6 is not limited by the above-mentioned lead material, and those skilled in the art can specifically select the material for the discharge terminal 6 according to the actual situation.

The anode 3 is made of copper material.

The insulating sleeve 2 is made of ceramic material.

The anode insulating layer 4 is made of Teflon material.

The micropores 5 are circular.

As shown in FIG. 1 , the pulsed plasma thruster with a microporous insulating anode according to the embodiment of the present invention includes a flat cathode 1, and the front discharge end 6 of the cathode 1 is made into a wedge shape, which is used to confine the insulation of the generated plasma. Canister 2 and anode insulating layer 4 with pores 5 surrounding anode 3 , and anode 3 .

The ratio of the length to the thickness of the cathode discharge end 6 is 4:3-1:1, specifically length/thickness=2:1 in this embodiment. The material of the plate-shaped portion of the cathode 1 is a ferrous metal with good magnetic conductivity.

The plate-shaped anode 3 is connected to the ground through a metal wire, and the anode 3 is wrapped by an anode insulating layer with micropores 5 .

For ease of understanding, detailed dimensions of a set of discharge electrodes are given below. The discharge end of the cathode 1 is made of lead metal, the total length of the cathode is 24mm, the length of the flat part of the cathode 1: width: thickness = 20mm: 5mm: 2mm, the length of the wedge-shaped discharge end is 4mm, the width of the top of the discharge end: thickness =: 5mm : 2mm. The length:width:thickness=4mm:5mm:2mm of the plate-shaped part of the anode 3, the length of the horn-shaped part is 10mm, the opening angle is 30 degrees, and the material is metal copper. The thickness of the anode insulating layer was 2 mm. The micropore 5 is located at the geometric center of the inner surface of the trumpet-shaped anode, and the micropore 5 is cylindrical with a radius of 0.5 mm.

The cathode 1 is connected to the negative high voltage terminal of the external discharge circuit. The discharge power supply adopts the form of pulse discharge, and its specific discharge circuit is shown in Figure 2. The 220V AC power supply is boosted by the transformer and converted by the voltage-doubling rectifier circuit to charge the capacitor _C2 . When the ignition pulse is applied to the three-point gap, the three-point gap is turned on, and a loop is formed by C ₂ , 27Ω resistance, 240μH inductance and the vacuum gap, and the vacuum gap breaks down to produce a discharge phenomenon. The cathode is connected to the high-voltage terminal of the power supply through the binding post, and the anode is grounded through the wire.

FIG. 5 is a graph showing the density distribution of plasma generated by discharge using the non-insulated anode electrode shown in FIG. 3 and the microporous insulated anode electrode with a microporous diameter of 1 mm. It can be seen from Fig. 5 that the plasma density generated by the microporous insulating anode electrode is higher than that of the non-anodic insulating electrode. It shows that a higher density plasma source can be obtained by using the microporous insulating anode electrode structure.

FIG. 6 is a graph showing the propagation velocity distribution of plasma generated by discharge using the non-insulated anode electrode as shown in FIG. 3 and the microporous insulated anode electrode when the microporous diameter is 1 mm. It can be seen from Fig. 6 that the propagation velocity of the plasma generated by the microporous insulating anode electrode is higher than that of the non-anodic insulating electrode. It shows that a higher energy plasma source can be obtained by using the microporous insulating anode electrode structure.

Comparative Test

Test 1. Test test of plasma generation effect after discharge of electrode structure with three different anodes:

During the discharge experiment, the electrode structure with three different anodes was studied. The three electrode structures are the non-insulated anode structure with exposed anode as shown in Fig. And the microporous insulating anode structure shown in Figure 1. For the bare metal anode electrode structure, the cathode 1 is made of lead metal, the total length of the cathode is 24mm, the length of the flat part of the cathode 1: width: thickness = 20mm: 5mm: 2mm, the length of the wedge-shaped discharge end is 4mm, and the width of the top of the discharge end: Thickness =: 5mm: 2mm. The length:width:thickness=4mm:5mm:2mm of the plate-shaped part of the anode 3, the length of the horn-shaped part is 10mm, the opening angle is 30 degrees, and the material is metal copper. In comparison, for the insulated anode electrode structure, the material of the insulating layer 4 that wraps the anode is EVA, and the thickness of the anode insulating layer is 2 mm. For the microporous insulated anode electrode structure, the micropore 5 is located at the geometric center of the inner surface of the trumpet-shaped anode, and the micropore 5 is cylindrical with a radius of 0.5 mm.

Using pulsed plasma thrusters with different anode structures to discharge, the experimentally measured plasma generation effects are shown in Table 1.

Table 1 Plasma measurement results under different anode structures

It can be seen from the parameters in Table 1 that under the condition of equal discharge voltage, the cathode current amplitude is 112A and the anode current amplitude is 60A when the non-insulated anode electrode structure discharges. The anode current amplitude only accounts for 53% of the cathode current amplitude. The analysis shows that this is because part of the electrons generated by the discharge are ejected along the axial direction of the insulating sleeve and do not enter the anode. When the fully insulated anode electrode structure discharges, the cathode current amplitude is 86A; since the anode metal is completely wrapped by the EVA insulating material, the measured anode current amplitude is 0. While the microporous insulated anode electrode structure discharges the cathode current amplitude is 112A, the anode current amplitude is 48A.

It can be seen from the plasma measurement parameters that the density peak of the plasma jet generated by the discharge of the non-insulated anode electrode structure is the lowest and the propagation velocity is the smallest; the jet length of the plasma generated by the insulated anode electrode structure is not significantly improved. Compared with the non-insulated anode electrode structure, after wrapping the metal anode with an insulating layer with micropores, the peak density and propagation speed of the generated plasma jet are increased by 8.9 times and 1.30 times, respectively. In conclusion, the existence of the microporous structure on the anode insulating layer improves the performance of the plasma jet.

Experiment 2. Test of the influence of micropore size on the effect of electrode plasma generation:

during the discharge experiment. Based on the structure of the microporous insulating anode electrode, the effect of the micropore size on the plasma generation effect was explored. The plasma generation effect is shown in Table 2.

Table 2 Plasma measurement results under different micropore sizes

From the parameters in Table 2, it can be seen that the size of the micropores has no significant effect on the amplitude of the discharge voltage between the electrodes and the amplitude of the cathode current. However, the size of the micropores is reduced, and the amplitude of the anode current is significantly reduced. The analysis shows that the use of an insulated anode electrode structure with a smaller pore size reduces the number of charged particles entering the electrode.

7 to 8, it can be seen that when the diameter of the micropore is reduced from 3.0 mm to 0.2 mm, the density, propagation velocity and jet length of the plasma increase by 3.3 times, 3.56 times and 228 times, respectively. Therefore, the use of an insulated anode electrode structure with smaller micropores improves the resulting plasma spray performance.

To sum up, the electrode structure with the microporous insulating anode of the present invention reduces the number of charged particles entering the electrode without affecting the generation of plasma, so that more plasma is ejected to form a thrust source, and the the ejection performance of the plasma.

By adopting a microporous structure with a smaller size, the loss of the plasma can be further reduced, and the density and propagation speed of the plasma source can be improved.

Those of ordinary skill in the art can understand that: the components of the apparatus in the embodiment of the present invention may be distributed in the apparatus of the embodiment according to the description of the embodiment, and may also be located in one or more apparatuses different from this embodiment by making corresponding changes . The components of the above-mentioned embodiments may be combined into one component, or may be further divided into multiple sub-components.

The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. Substitutions should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims (10)

1. The utility model provides a pulse plasma propeller with micropore insulation positive pole which characterized in that: comprises a cathode (1), an insulating sleeve (2) sleeved on the cathode (1), and an anode (3) fixedly sleeved at one end of the insulating sleeve (2);

a discharge end (6) is arranged at one end of the cathode (1) close to the anode (3), and the anode (3) comprises a straight cylinder part (31) and a horn opening part (32);

the inner surface of the straight barrel part (31) is connected with the outer surface of the insulating sleeve (2); the part of the anode (3) which is not contacted with the insulating sleeve (2) is wrapped with an anode insulating layer (4);

micropores (5) are arranged on the insulating layer (4) on the inner surface of the horn opening part (32);

the flat plate end of the cathode (1) is electrically connected with an external circuit negative high-voltage terminal, and the anode (3) is grounded.

2. The pulsed plasma thruster with a micro-porous insulated anode of claim 1 wherein: the cathode (1) is plate-shaped.

3. The pulsed plasma thruster with a micro-porous insulated anode of claim 2 wherein: the discharge end (6) is in a protruding shape arranged at the front end of the plate-shaped cathode (1).

4. The pulsed plasma thruster with a micro-porous insulated anode of claim 3, wherein: the flat end surface of the cathode (1) is in contact with the inner wall of the insulating sleeve (2).

5. The pulsed plasma thruster with a micro-porous insulated anode of claim 4 wherein: the micropore (5) is positioned at the geometric center of the insulating layer (4) on the inner surface of the horn opening part (32).

6. The pulsed plasma thruster with a micro-porous insulated anode of any one of claims 1 to 5, wherein: the cathode (1) is made of a magnetic conductive metal material, and the discharge end (6) is made of lead.

7. The pulsed plasma thruster with a micro-porous insulated anode of any one of claims 1 to 5, wherein: the anode (3) is made of a copper material.

8. The pulsed plasma thruster with a micro-porous insulated anode of any one of claims 1 to 5, wherein: the insulating sleeve (2) is made of a ceramic material.

9. The pulsed plasma thruster with a micro-porous insulated anode of any one of claims 1 to 5, wherein: the anode insulating layer (4) is made of Teflon material.

10. The pulsed plasma thruster with a micro-porous insulated anode of claim 1 wherein: the micropores (5) are circular.

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