Hall thruster anode assembly

Abstract

The invention provides an anode assembly of a Hall thruster. The anode assembly at least comprises a magnetic screen, a gas distribution ring and an anode, the magnetic screen at least comprises an inner ring and an outer ring which are concentrically arranged, and the outer wall of the inner ring and the inner wall of the outer ring are connected through a bottom ring to form an annular cavity with an opening in the top end. The gas distribution ring is arranged behind the annular cavity and divides the annular cavity into a first-stage gas buffer cavity and a second-stage gas buffer cavity in the axial direction; the anode is arranged in the secondary gas buffer cavity and is connected with the upper end surface of the gas distribution ring; the bottom ring is provided with a first through hole used for communicating a gas supply pipe with the first-stage gas buffer cavity. The gas distribution ring is provided with a second through hole communicated with the primary gas buffer cavity and the anode inner cavity; and the anode is provided with a plurality of inclined holes which are communicated with the anode inner cavity and the secondary gas buffer cavity.

Description

Technical Field

[0001] The invention relates to the field of space propulsion technology, in particular to an anode assembly of a Hall thruster. Background Art

[0002] Hall thrusters are widely used in spacecraft position keeping, orbit transfer, attitude control and interstellar navigation due to their simple structure, high efficiency and long service life. In recent years, with the rapid development of commercial aerospace, krypton propellant has been widely used, but krypton has low ionization efficiency and low working efficiency. In addition, krypton thrusters have poor discharge stability. In severe cases, low-frequency oscillations with large amplitudes will cause the thrusters to extinguish, affecting the working stability of the thrusters. Therefore, it is urgent to optimize the performance of Hall thrusters. Summary of the invention

[0003] In order to solve the above technical problems, the present invention proposes a Hall thruster anode assembly. By reasonably optimizing and improving the anode structure, the residence time of the gas working medium in the discharge channel is increased. The conical design of the anode structure makes the cross-sectional area of ​​the discharge channel gradually increase along the outlet direction, thereby improving the overall performance of the Hall thruster.

[0004] A Hall thruster anode assembly provided by the present invention comprises at least a magnetic shield, a gas distribution ring and an anode; the magnetic shield comprises at least an inner ring and an outer ring which are arranged concentrically, and the outer wall of the inner ring is connected to the inner wall of the outer ring through a bottom ring to form an annular cavity with an opening at the top; the gas distribution ring is arranged in the annular cavity to divide the annular cavity into a primary gas buffer cavity and a secondary gas buffer cavity along the axial direction; the anode is arranged in the secondary gas buffer cavity and connected to the upper end face of the gas distribution ring; wherein the bottom ring is provided with a first through hole for connecting a gas supply pipe and the primary gas buffer cavity; the gas distribution ring is provided with a second through hole connecting the primary gas buffer cavity and the anode inner cavity; the anode is provided with a plurality of inclined holes connecting the anode inner cavity and the secondary gas buffer cavity.

[0005] In one embodiment, the cross-section of the anode is a conical structure, and the top thereof adopts an arc transition.

[0006] In one embodiment, the anode includes an inner distribution ring and an outer distribution ring which are spaced apart on the upper end surface of the gas distribution ring, and an anode top which is arranged on the top of the inner distribution ring and the outer distribution ring; an extension section is provided on the lower end surface of the anode top; the extension section extends between the inner distribution ring and the outer distribution ring, and forms the anode cavity together with the outer side surface of the inner distribution ring and the inner side surface of the outer distribution ring.

[0007] In one embodiment, the inclined holes include a plurality of first inclined small holes circumferentially evenly distributed on the inner distribution ring, and a plurality of second inclined small holes circumferentially evenly distributed on the outer distribution ring; each of the first inclined small holes circumferentially diverges from the anode inner cavity to the secondary gas buffer cavity; each of the second inclined small holes circumferentially diverges from the anode inner cavity to the secondary gas buffer cavity.

[0008] In one embodiment, the angle between the axis of the first inclined hole and the tangent plane is an acute angle X; the angle between the axis of the second inclined hole and the tangent plane is an acute angle Y; wherein the angle of X is equal to the angle of Y.

[0009] In one embodiment, the upper end surface of the gas distribution ring is provided with an inner ring boss and an outer ring boss that are concentric and have different diameters; the bottom of the inner distribution ring is provided with a groove that matches the inner ring boss, and the bottom of the outer distribution ring is provided with a groove that matches the outer ring boss; the second through holes are evenly distributed between the inner ring boss and the outer ring boss along the circumference of the gas distribution ring.

[0010] In one embodiment, the cone angle of the cone structure ranges from 8° to 25°.

[0011] In any of the above embodiments, bosses of equal height are respectively provided on the outer ring of the inner ring and the inner ring of the outer ring close to the bottom ring, and the gas distribution ring is connected to the inner ring and the outer ring via the bosses.

[0012] In one embodiment, the top of the magnetic shield is higher than the top of the anode.

[0013] In one embodiment, the number of the first inclined holes is equal to the number of the second inclined holes.

[0014] The Hall thruster anode assembly of the present invention has at least one of the following beneficial effects:

[0015] 1. The Hall thruster anode assembly of the present invention provides inclined small holes on the inner and outer distribution rings of the anode, so that the gas working medium rotates and flows out along the inclined small holes of the anode, thereby reducing the axial flow velocity of the gas and prolonging the residence time of the gas in the channel, thereby significantly improving the ionization efficiency of the working medium (especially krypton working medium).

[0016] 2. The anode of the Hall thruster anode assembly of the present invention is a conical structure, so that the cross-sectional area of ​​the discharge channel gradually increases along the outlet direction, which to a certain extent suppresses the thruster low-frequency discharge oscillation and improves the thruster discharge stability.

[0017] 3. The anode position of the Hall thruster anode assembly of the present invention is greatly extended downstream of the discharge channel, which shortens the length of the ionization acceleration zone, is more conducive to ion acceleration, and improves thruster performance.

[0018] 4. The magnetic shield, discharge channel, anode and gas distribution ring of the Hall thruster anode assembly of the present invention adopt an integrated structural design. The entire discharge channel is at the same potential as the anode. Compared with the traditional structure, the anode surface area is greatly increased, the electron heat deposition per unit area of ​​the anode is reduced, the anode temperature is lowered, the electron acceptance efficiency and the overall working performance of the thruster are improved.

[0019] 5. The anode assembly of the Hall thruster according to the embodiment of the present invention has a simple and lightweight structure, which greatly reduces the weight of the entire thruster.

[0020] Those skilled in the art will recognize additional features and advantages upon reading the detailed description and upon viewing the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a schematic diagram of the overall structure of the Hall thruster anode assembly according to an embodiment of the present invention.

[0023] Figure 2 Schematic diagram of the cross section of the anode assembly of the Hall thruster according to the embodiment of the present invention.

[0024] Figure 3 It is a schematic structural diagram of the gas distribution ring and the anode docking portion of an embodiment of the present invention.

[0025] Figure 4 1 is a schematic cross-sectional view of an aa section of a Hall thruster anode assembly according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The features and exemplary embodiments of various aspects of the present invention will be described in detail below. In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present invention and are used to illustrate the principles of the present invention, and are not configured to limit the present invention. In addition, the structural components in the drawings are not necessarily drawn to scale. For example, the sizes of some structural components or areas in the drawings may be enlarged for other structural components or areas to help understand the embodiments of the present invention.

[0027] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of the embodiments of the present invention. In the description of the present invention, it should be noted that, unless otherwise specified, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0028] In addition, the terms "include", "comprise", "have" or any other variations thereof are intended to cover non-exclusive inclusion, so that a structure or component including a series of elements includes not only those elements, but also other mechanical elements that are not explicitly listed or inherent in the structure or component. In the absence of more restrictions, the elements defined by the sentence "include..." do not exclude the existence of other identical elements in the article or device including the elements.

[0029] Spatially related terms such as "below", "beneath", "under", "low", "above", "on", "high", etc. are used to facilitate description to explain the positioning of one element relative to a second element, indicating that these terms are intended to cover different orientations of the device in addition to orientations different from those shown in the figures. In addition, for example, "one element is above / below another element" can mean that the two elements are in direct contact, or that there are other elements between the two elements. In addition, terms such as "first", "second", etc. are also used to describe various elements, regions, parts, etc., and should not be regarded as limiting. Similar terms represent similar elements throughout the description.

[0030] For those skilled in the art, the present invention can be implemented without some of these specific details. The following description of the embodiments is only intended to provide a better understanding of the present invention by showing examples of the present invention.

[0031] If the Hall thruster uses krypton as the working fluid, due to its small atomic radius, high ionization energy, fast atomic movement speed, and short residence time in the discharge channel, it is easy to cause its ionization performance to be poor. In addition, at the same power, the efficiency of krypton working fluid thrusters is usually lower than that of xenon, and the heat loss caused by electron energy deposition is aggravated, causing the anode temperature to increase. For high-power Hall thrusters, the voltage is higher and the current is larger. The anode will also face the huge heat load problem caused by the large electron current, which will cause the anode to turn red, and in severe cases, it will cause the anode to self-melt. In addition, the discharge stability of krypton working fluid thrusters is poor. In severe cases, low-frequency oscillations with large amplitudes will cause the thruster to extinguish, affecting the working stability of the thruster.

[0032] The advantage of krypton thrusters lies in their higher specific impulse. However, the anode of the traditional structure is far away from the discharge channel, and the ion acceleration zone in the channel is longer, which causes the energy loss of ions on the wall to increase, the thrust decreases, and the specific impulse is reduced. Therefore, in order to solve the above problems, the anode structure must be reasonably optimized and improved to better play the performance of the thruster under krypton working fluid.

[0033] In view of this, the present invention provides a high-performance Hall thruster anode assembly. Figure 1 and Figure 2 The present invention provides a Hall thruster anode assembly, which at least includes a magnetic shield 1, a gas distribution ring 2 and an anode 3. The magnetic shield 1 is an annular cavity with an opening at one end, and the gas distribution ring 2 is a thin-walled circular ring structure. The gas distribution ring 2 is arranged in the annular cavity of the magnetic shield 1. The magnetic shield 1 at least includes an inner ring 11 and an outer ring 12 which are arranged concentrically, and the outer wall of the inner ring 11 and the inner wall of the outer ring 12 are connected through a bottom ring 13 to form an annular cavity with an opening at the top. After the gas distribution ring 2 is arranged in the annular cavity of the magnetic shield 1, it is divided into a primary gas buffer cavity A and a secondary gas buffer cavity B (metal discharge channel) along the axial direction. The primary buffer cavity A is located at the lower end surface of the gas distribution ring 2, and the secondary buffer cavity B is located at the upper end surface of the gas distribution ring 2. The anode 3 is arranged in the secondary gas buffer cavity B and is connected to the upper end surface of the gas distribution ring 2.

[0034] In this embodiment, the bottom ring 13 is provided with a first through hole for connecting the gas supply pipe 4 and the first-level gas buffer chamber A. The gas supply pipe 4 is inserted into the first through hole and fixed by welding along the circumference thereof, and the gas supply pipe 4 is used to provide gas working medium for the Hall thruster anode assembly of this embodiment. The gas distribution ring 2 is provided with a second through hole connecting the first-level gas buffer chamber A and the anode inner chamber C, and the anode 3 is provided with a plurality of inclined holes connecting the anode inner chamber C and the second-level gas buffer chamber B.

[0035] The Hall thruster anode assembly of the embodiment of the present invention is provided with gas working medium through the gas supply pipe 4. First, the primary gas buffer chamber A buffers and equalizes the incoming flow. The working medium after the first equalization enters the inner cavity C of the anode 3 through the second through hole, and then enters the gas buffer chamber B (metal discharge channel) through the inclined hole for secondary buffering before output. Figure 2 The flow path of the gas working medium is marked. The gas working medium flows out along the anode inclined hole in a rotation manner, which reduces the axial flow velocity of the gas, prolongs the residence time of the gas in the channel, and improves the ionization efficiency of the working medium (especially krypton working medium).

[0036] In view of the higher voltage and greater current of high-power Hall thrusters, the anode will also face the huge heat load problem caused by the large electron current, which can easily cause the anode to turn red, and in severe cases, it will cause the anode to self-melt. Based on this, the magnetic screen, gas distribution ring, anode and discharge channel of the embodiment of the present invention adopt an integrated design, and the entire discharge channel is at the same potential as the anode. Compared with the traditional anode structure, the anode surface area is greatly increased, the anode temperature is reduced, the electron acceptance efficiency is increased, and the overall working performance of the Hall thruster is improved. At the same time, the entire structure also bears the functions of plasma discharge, gas distribution and magnetic conductivity. The component structure is simple and light, which reduces the weight of the thruster.

[0037] See also Figure 2 In one embodiment, the cross-section of the anode 3 is a conical structure, and the cone angle thereof is in the range of 8° to 25°. The conical anode can gradually increase the cross-sectional area of ​​the discharge channel (secondary buffer cavity) toward the outlet side, which to a certain extent suppresses the thruster low-frequency discharge oscillation and improves the thruster discharge stability. As a more preferred choice, the cone angle of the anode 3 is in the range of 8° to 15°. In order to facilitate processing, the top of the anode 3 can adopt an arc transition.

[0038] During the operation of the thruster, the anode needs to withstand the energy deposition caused by frequent electron sputtering bombardment. In addition, the anode cannot affect the original magnetic field configuration, so the material of the anode is non-magnetic stainless steel.

[0039] See also Figure 2 and Figure 3 In one embodiment, in order to facilitate the processing and forming of the anode, the anode 3 includes an inner distribution ring 31 and an outer distribution ring 32 which are arranged at intervals on the upper end surface of the gas distribution ring 2, and an anode top 33 which is arranged on the top of the inner distribution ring 31 and the outer distribution ring 32. Among them, the lower end surface of the anode top 33 is provided with an extension section, and the extension section extends between the inner distribution ring 31 and the outer distribution ring 32. The extension section of the anode top 33 and the outer side surface of the inner distribution ring 31 and the inner side surface of the outer distribution ring form an anode cavity C.

[0040] When assembling the anode 3 and the gas distribution ring 2 , the inner distribution ring 31 and the outer distribution ring 32 can be directly welded to the upper end surface of the gas distribution ring 2 .

[0041] Alternatively, the upper end surface of the gas distribution ring 2 may be provided with an inner ring boss 21 and an outer ring boss 22 of concentric and different diameters, the bottom of the inner distribution ring 31 may be provided with a groove matching the inner ring boss 21, and the bottom of the outer distribution ring 32 may be provided with a groove matching the outer ring boss 22. In this embodiment, the inner ring boss 21 may be fixed by welding after being matched with the groove of the inner distribution ring 31, and the outer ring boss 22 may be fixed by being matched with the groove of the outer distribution ring 32. Afterwards, the anode top 33 is abutted between the inner anode distribution ring 31 and the outer distribution ring 32, and the extension section placed between the outer ring of the inner distribution ring 31 and the inner ring of the outer distribution ring 32 is used for limiting, and finally the anode top 33 is fixed by circumferential welding to the inner distribution ring 31 and the outer distribution ring 32.

[0042] It should be noted that the distance from the inner ring boss 21 to the inner ring 11 is equal to the distance from the outer ring boss 22 to the outer ring 12 .

[0043] The inner ring boss 21 and the outer ring boss 22 are of the same height, and the height is smaller than the thickness of the gas distribution ring 2, so as to reduce the weight as much as possible without affecting the subsequent welding.

[0044] The conical anode structure in this embodiment can gradually increase the cross-sectional area of ​​the discharge channel toward the outlet side, which to a certain extent suppresses the thruster's low-frequency discharge oscillation and improves the thruster's discharge stability. The anode position is greatly extended downstream of the discharge channel, shortening the length of the ionization acceleration zone, which is more conducive to ion acceleration and improves thruster performance.

[0045] See also Figure 3 and Figure 4 In the above embodiment, the second through hole for connecting the primary gas buffer cavity A and the anode inner cavity C is placed between the inner ring boss 21 and the outer ring boss 22. Specifically, the second through hole is a plurality of small holes 23 uniformly distributed between the inner ring boss 21 and the outer ring boss 22 along the circumference of the gas distribution ring 2. Further, the number of the small holes 23 can be 10 or 12.

[0046] See also Figure 4In one embodiment, the inclined holes include a plurality of first inclined small holes 311 uniformly distributed circumferentially on the inner distribution ring 31, and a plurality of second inclined small holes 321 uniformly distributed circumferentially on the outer distribution ring 32. Among them, the number of the first inclined small holes 311 is the same as the number of the second inclined small holes 321. Each first inclined small hole 311 circumferentially diverges from the anode inner cavity C to the secondary gas buffer cavity B, and each second inclined small hole 321 circumferentially diverges from the anode inner cavity C to the secondary gas buffer cavity B. It should be noted that the rotation direction of the gas working medium after passing through the first inclined small hole and the second inclined small hole is the same. That is to say, when looking at the thruster anode of this embodiment from a certain angle, if the gas working medium diverging through the first inclined small hole rotates counterclockwise along the secondary gas buffer cavity B, the gas working medium diverging through the second inclined small hole must also rotate counterclockwise along the secondary gas buffer cavity B.

[0047] Furthermore, the angle between the axis of the first inclined small hole and the tangent plane is an acute angle X, and the angle between the axis of the second inclined small hole and the tangent plane is an acute angle Y. The angle of X is equal to the angle of Y, and the angle range of X and Y is 15° to 40°.

[0048] The gas working medium rotates and flows out through the inclined small holes of the anode of this embodiment, which reduces the axial flow velocity of the gas working medium, prolongs the residence time of the gas working medium in the discharge channel (secondary gas buffer chamber), and improves the ionization efficiency of the working medium (especially krypton working medium).

[0049] The anode of the embodiment of the present invention adopts a structure in which the inner distribution ring and the outer distribution ring are separated, so as to facilitate the processing of inclined small holes on the inner and outer distribution rings.

[0050] See also Figure 3 In any of the above embodiments, in order to facilitate the positioning and installation of the gas distribution ring, bosses T of equal height are respectively provided on the outer ring of the inner ring 11 and the inner ring of the outer ring 12 on the side close to the bottom ring. The gas distribution ring 2 is placed on the side of the two bosses away from the bottom ring, and is axially positioned by the bosses, and then fixedly connected to the inner ring 11 and the outer ring 12 by circumferential welding.

[0051] In the above embodiment, the top of the magnetic shield is higher than the top of the anode, that is, the top of the anode is 1 mm to 3 mm lower than the outlet of the discharge channel. The anode position extends downstream of the discharge channel, shortening the length of the ionization acceleration zone, increasing the magnetic field gradient, and being more conducive to ion acceleration, thereby improving thruster performance.

[0052] The above embodiments can be combined with each other and have corresponding technical effects.

[0053] The Hall thruster anode assembly of the present invention optimizes and improves the anode structure in a reasonable manner, thereby increasing the ionization rate of the gas working fluid (especially the krypton working fluid with a relatively high ionization energy), reducing the anode temperature, and improving the thruster performance.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A Hall thruster anode assembly, characterized in that: At least: A magnetic shield, a gas distribution ring and an anode; the magnetic shield at least comprises an inner ring and an outer ring arranged concentrically, the outer wall of the inner ring is connected to the inner wall of the outer ring through a bottom ring to form an annular cavity with an opening at the top; the gas distribution ring is arranged in the annular cavity to divide the cavity into a primary gas buffer cavity and a secondary gas buffer cavity along the axial direction; the anode is arranged in the secondary gas buffer cavity and connected to the upper end surface of the gas distribution ring; Among them, the bottom ring is provided with a first through hole for connecting the gas supply pipe and the primary gas buffer chamber; the gas distribution ring is provided with a second through hole connecting the primary gas buffer chamber and the anode inner cavity; the anode is provided with a plurality of inclined holes connecting the anode inner cavity and the secondary gas buffer chamber.

2. The Hall thruster anode assembly according to claim 1, characterized in that: The cross-section surface of the anode is a conical structure, and the top thereof adopts an arc transition.

3. The Hall thruster anode assembly according to claim 2, characterized in that: The anode includes an inner distribution ring and an outer distribution ring which are arranged at intervals on the upper end surface of the gas distribution ring, and an anode top which is arranged on the top of the inner distribution ring and the outer distribution ring; The lower end surface of the anode top is provided with an extension section; the extension section extends between the inner distribution ring and the outer distribution ring, and forms the anode cavity together with the outer side surface of the inner distribution ring and the inner side surface of the outer distribution ring.

4. The Hall thruster anode assembly according to claim 3, characterized in that: The inclined holes include a plurality of first inclined small holes circumferentially evenly distributed on the inner distribution ring, and a plurality of second inclined small holes circumferentially evenly distributed on the outer distribution ring; each of the first inclined small holes circumferentially diverges from the anode inner cavity to the secondary gas buffer cavity; each of the second inclined small holes circumferentially diverges from the anode inner cavity to the secondary gas buffer cavity.

5. The Hall thruster anode assembly according to claim 4, characterized in that: The angle between the axis of the first inclined small hole and the tangent plane is an acute angle X; the angle between the axis of the second inclined small hole and the tangent plane is an acute angle Y; Here, the angle of X is equal to the angle of Y.

6. The Hall thruster anode assembly according to claim 3, characterized in that: The upper end surface of the gas distribution ring is provided with an inner ring boss and an outer ring boss of concentric and different diameters; the bottom of the inner distribution ring is provided with a groove matching the inner ring boss, and the bottom of the outer distribution ring is provided with a groove matching the outer ring boss; The second through holes are evenly distributed between the inner ring boss and the outer ring boss along the circumferential direction of the gas distribution ring.

7. The Hall thruster anode assembly according to claim 2, characterized in that: The cone angle of the cone structure ranges from 8° to 25°.

8. The Hall thruster anode assembly according to any one of claims 1 to 7, characterized in that: Bosses of equal height are respectively arranged on the outer ring of the inner ring and the inner ring of the outer ring close to the bottom ring, and the gas distribution ring is connected with the inner ring and the outer ring through the bosses.

9. The Hall thruster anode assembly according to claim 8, characterized in that: The top of the magnetic shield is higher than the top of the anode.

10. The Hall thruster anode assembly according to claim 5, characterized in that: The number of the first inclined small holes is equal to the number of the second inclined small holes.

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