A dual-anode micro-cathode arc propulsion device

Abstract

The present invention belongs to the field of micro-newton arc thrusters, and relates to a dual-anode micro-cathode arc propulsion device, comprising: an inner anode, an inner insulating ceramic layer, a cathode, an outer insulating ceramic layer, an outer anode, an insulating sleeve, a positioning cover, a spring, a back cover, and an outer shell. The inner insulating ceramic layer is tightly sleeved between the inner anode and the cathode, the outer insulating ceramic layer is tightly sleeved on the cathode, and the outer anode is tightly placed on the outer insulating ceramic layer. The positioning cover, the outer anode, the insulating sleeve, and the outer insulating ceramic layer are fixed to the outer shell by screws, the outer shell is sleeved on the cathode, and the lower end of the cathode and the back cover clamp the spring. The present invention solves the problem of uneven cathode ablation of the micro-cathode arc thruster and prolongs the service life of the thruster.

Description

Technical Field

[0001] The invention belongs to the field of micro-newton-class arc thrusters and relates to a dual-anode micro-cathode arc propulsion device. Background Art

[0002] Space propulsion is used for spacecraft during the space flight phase. Its function is to provide power for spacecraft attitude control, north-south position keeping, orbital maneuvers and deorbiting. Space propulsion technology can generally be divided into chemical propulsion and electric propulsion, as well as some other propulsion technologies (such as nuclear propulsion and solar sail propulsion technology). At present, electric propulsion technology has gradually become the preferred solution for space small thrust propulsion devices due to its high specific impulse advantage; micro cathode arc thrusters have great application value due to their small size, high specific impulse, low power consumption, long life, variable thrust and low pollution performance advantages.

[0003] The microcathode arc thruster (μ-CAT for short) is a new type of space electric thruster that uses arc discharge under vacuum conditions to ablate solid metal materials, generate metal vapor, and ionize the metal vapor to generate plasma. Under magnetic confinement conditions, the plasma is focused and axially accelerated to generate thrust. Compared with other types of electric thrusters, μ-CAT uses solid-state propulsion fluid. The metal cathode serves as both the discharge cathode and the thruster's propulsion fluid. It does not require an additional fluid storage and supply system. At the same time, it has the advantages of simple structure, small size, light system mass, small power demand, long service life, variable thrust, and low reflux pollution.

[0004] However, due to the structural problem of the single anode, the discharge of the traditional micro-cathode arc thruster starts from one side. During the discharge process, the inner layer of the cathode is more ablated, the outer layer is less ablated, and the radial ablation is uneven, so the entire cathode cannot be ablated, and thus the stability of long-term operation cannot be fully guaranteed to achieve the expected goal. Although a lot of research has been done at home and abroad, the problem of uneven cathode ablation has not been completely solved.

[0005] Therefore, based on the existing μ-CAT structure, a dual-anode structural design is proposed to provide two internal and external discharge channels for the cathode. When one channel causes the resistance between the cathode and the anode to increase due to excessive ablation, the other channel begins to ablate, so that the resistance between the cathode and the anode is balanced, and the inner and outer layers of the cathode are ablated, so that the cathode is continuously supplied, fundamentally solving the problem of uneven cathode ablation and improving the working life of the thruster. Summary of the invention

[0006] The invention provides a dual-anode micro-cathode arc propulsion device to solve the problems of uneven cathode ablation and short service life of a traditional micro-cathode arc thruster.

[0007] The technical solution of the present invention is as follows:

[0008] A dual-anode micro-cathode arc propulsion device, comprising: an inner anode, an inner insulating ceramic layer, a cathode, an outer insulating ceramic layer, an outer anode, an insulating sleeve, a positioning cover, a spring, a rear cover, and a shell;

[0009] The inner insulating ceramic layer is sleeved between the inner anode and the cathode, the outer insulating ceramic layer is sleeved on the cathode, the outer anode is placed above the outer insulating ceramic layer, and the positioning cover, the outer anode, the insulating sleeve, and the outer insulating ceramic layer are fixed to the outer shell with screws. The outer shell is sleeved on the outside of the cathode, a spring is arranged between the lower end of the cathode and the back cover, and gaskets are arranged at the upper and lower ends of the spring. The back cover and the outer shell are connected by screws; the inner anode passes through the back cover and is tightly fixed to the back cover by a nut, and the spring is in a compressed state at this time.

[0010] Furthermore, the inner insulating ceramic layer and the outer insulating ceramic layer are made of alumina ceramics, and the surface is coated with a carbon film.

[0011] Furthermore, the inner anode and the outer anode are made of copper, and the bottom of the inner anode has threads.

[0012] Furthermore, the cathode material is titanium.

[0013] Furthermore, the spring is a high alloy spring with a length of 15 mm.

[0014] Furthermore, the insulating sleeve, the positioning cover and the back cover are made of polytetrafluoroethylene.

[0015] Furthermore, the shell material is hard aluminum.

[0016] Beneficial effects of the present invention:

[0017] (1) The present invention proposes a new dual-anode structural design to solve the problem of uneven ablation, making the cathode ablation radius larger and increasing the ablation amount of the cathode outer ring.

[0018] (2) The dual anode structure of the present invention can support a cathode with a greater radial thickness, thereby greatly improving the total thrust of the thruster.

[0019] (3) The dual anode structure design of the present invention allows the ceramics on both the inner and outer sides to contact and discharge with the cathode at the same time, thereby reducing ceramic erosion.

[0020] (4) The dual anode structure of the present invention reduces the power density of a single anode, lowers the operating temperature of the thruster, and provides more reliable performance.

[0021] (5) The present invention has low power consumption and small ceramic erosion, thus greatly extending the service life of the thruster. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of a dual-anode micro-cathode arc propulsion device according to an embodiment of the present invention.

[0023] Figure 2 It is a stereoscopic diagram of a dual-anode micro-cathode arc propulsion device according to an embodiment of the present invention.

[0024] In the figure: 1 inner anode; 2 inner insulating ceramic layer; 3 cathode; 4 positioning cover; 5 outer anode; 6 insulating sleeve; 7 outer insulating ceramic layer; 8 outer shell; 9 gasket; 10 spring; 11 back cover; 12 hexagonal nut; 13 spring washer; 14 flat gasket; 15 pan head screw. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Embodiment 1:

[0027] Figure 1 This is a schematic structural diagram of a dual-anode micro-cathode arc propulsion device according to an embodiment of the present invention. The inner insulating ceramic layer 2 is tightly sleeved on the inner anode 1, the cathode 3 is tightly sleeved on the inner insulating ceramic layer 2, the outer insulating ceramic layer 7 is tightly sleeved on the cathode 3, and the outer anode 5 is tightly placed on the outer insulating ceramic layer 7. Four pan head screws 15 pass through the positioning cover 4, the insulating sleeve 6, and the outer insulating ceramic layer 7 to connect with the outer shell 8 to fix the outer anode 5. The lower end of the cathode 3 is in close contact with the gasket 9, the spring 10 is located between the two gaskets and in close contact, and the other gasket is in close contact with the back cover 11. The outer shell 8 is sleeved on the outside of the cathode 3, and the back cover 11 is connected to the outer shell 8 by four pan head screws 15. The inner anode 1 passes through the back cover 11 and is tightly fixed to the back cover 11 by two hexagonal nuts 12; the pan head screws 15 are fixed to the back cover 11 by spring washers 13 and flat washers 14.

[0028] Embodiment 2:

[0029] The thruster adopts pulse discharge working mode, with a high-voltage IGBT power supply of 1000V at a frequency of 10Hz and an output voltage of 1000V. The power supply maintains discharge time of about 150μs. The cathode and the inner and outer anodes can form a discharge circuit to generate vacuum arc discharge. The discharge will burn the cathode metal, generate metal vapor, and ionize the metal vapor to generate plasma. Under magnetic confinement conditions, the plasma is focused and axially accelerated to generate thrust. During each pulse signal time, the one with smaller resistance in the two discharge circuits will undergo breakdown discharge and burn the cathode metal on that side. Assume that the two anodes are anode ① and anode ②. When the cathode metal on the anode ① side is burned more, the distance between the cathode and the cathode increases, the distance of the exposed ceramic increases, the resistance on that side will increase, and the discharge will move to anode ②, burning the metal on the anode ② side. When the cathode on the anode side ② is more eroded, the spring will push the cathode forward, reducing the distance between the cathode and cathode on the anode side ①. At the same time, part of the metal vapor ablated on the side ② adheres to the exposed ceramic on the side ①, further reducing the resistance on the side ① and restoring discharge on the side ①. The above process is repeated to maintain the uniformity of cathode ablation.

[0030] Embodiment 3:

[0031] A dual-anode micro-cathode arc propulsion device, comprising: an inner anode 1, an inner insulating ceramic layer 2, a cathode 3, an outer insulating ceramic layer 7, an outer anode 5, an insulating sleeve 6, a positioning cover 4, a spring 10, a rear cover 11, and a housing 8;

[0032] The inner insulating ceramic layer 2 is sleeved between the inner anode 1 and the cathode 3, the outer insulating ceramic layer 7 is sleeved on the cathode 3, the outer anode 5 is placed above the outer insulating ceramic layer 7, the positioning cover 4, the outer anode 5, the insulating sleeve 6, and the outer insulating ceramic layer 7 are fixed to the outer shell 8 by screws, the outer shell 8 is sleeved on the outside of the cathode 3, a spring 10 is arranged between the lower end of the cathode 3 and the back cover 11, and gaskets are arranged at the upper and lower ends of the spring 10, and the back cover 11 and the outer shell 8 are connected by screws; the inner anode 1 passes through the back cover 11 and is tightly fixed to the back cover 11 by nuts, and the spring 10 is in a compressed state. The inner insulating ceramic layer 2 and the outer insulating ceramic layer 7 are made of alumina ceramics, and the surface is coated with a carbon film. The inner anode 1 and the outer anode 5 are made of copper, and the bottom of the inner anode 1 has threads. The cathode 3 is made of titanium. The spring 10 is a high alloy spring 10 with a length of 15 mm. The insulating sleeve 6, the positioning cover 4 and the back cover 11 are made of polytetrafluoroethylene. The shell 8 is made of hard aluminum.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dual-anode micro-cathode arc propulsion device, characterized in that: include: Inner anode (1), inner insulating ceramic layer (2), cathode (3), outer insulating ceramic layer (7), outer anode (5), insulating sleeve (6), positioning cover (4), spring (10), back cover (11), outer shell (8); The inner insulating ceramic layer (2) is sleeved between the inner anode (1) and the cathode (3), the outer insulating ceramic layer (7) is sleeved on the cathode (3), the outer anode (5) is placed above the outer insulating ceramic layer (7), the positioning cover (4), the outer anode (5), the insulating sleeve (6), and the outer insulating ceramic layer (7) are fixed to the outer shell (8) by screws, the outer shell (8) is sleeved on the outside of the cathode (3), a spring (10) is arranged between the lower end of the cathode (3) and the rear cover (11), gaskets are arranged at the upper and lower ends of the spring (10), and the rear cover (11) and the outer shell (8) are connected by screws; the inner anode (1) passes through the rear cover (11) and is tightly fixed to the rear cover (11) by nuts, and the spring (10) is in a compressed state at this time; The inner insulating ceramic layer (2) and the outer insulating ceramic layer (7) are made of alumina ceramics, and the surfaces are coated with a carbon film.

2. A dual-anode micro-cathode arc propulsion device as claimed in claim 1, characterized in that: The inner anode (1) and the outer anode (5) are made of copper, and the bottom of the inner anode (1) is threaded.

3. A dual-anode micro-cathode arc propulsion device as claimed in claim 1, characterized in that: The cathode (3) is made of titanium.

4. A dual-anode micro-cathode arc propulsion device as claimed in claim 2, characterized in that: The cathode (3) is made of titanium.

5. A dual-anode micro-cathode arc propulsion device as claimed in claim 1 or 4, characterized in that: The spring (10) is a high alloy spring (10) with a length of 15 mm.

6. A dual-anode micro-cathode arc propulsion device according to claim 1 or 4, characterized in that: The insulating sleeve (6), the positioning cover (4) and the rear cover (11) are made of polytetrafluoroethylene.

7. A dual-anode micro-cathode arc propulsion device as claimed in claim 1 or 4, characterized in that: The material of the shell (8) is hard aluminum.

8. A dual-anode micro-cathode arc propulsion device as claimed in claim 2, characterized in that: The material of the shell (8) is hard aluminum.

9. A dual-anode micro-cathode arc propulsion device as claimed in claim 3, characterized in that: The material of the shell (8) is hard aluminum.

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